Outstanding! That's a ton of LEDs... I bet the tree looks great! My WLED Christmas tree is now in its third year of use and still going strong. Thanks for taking a moment to comment and share what you found when using the I2C shifter.
I am a sub'r to your channel and have watched many of your videos and replicated many of your cookie board set ups from motion sensor triggered hallway lighting to WLED general setup lighting and have used the same WS2812 LEDs, I2C logic level shifters, ESP boards and everything else you've used/recommended and have had PERFECT results every time. I have had absolutely ZERO issues with the logic level shifter. I was doing some testing about a year ago and put 4 rolls of 300 WS2812 LED lights (TOTAL OF 1200 LEDS) using the ESP board and the logic level shifter and also a few power injection points in a few different areas and had the same brightness on LED number 1200 as I had on LED number 1. Also there was absolutely ZERO issues with what people are claiming when it comes to hesitation, delay, flickering and whatnot. The data channel was in flawless working order. That's my 2 cents about these wonderful logic level shifters. I will never have a LED project WITHOUT the I2C logic level shifter. Thanks for the video and sharing all of your awesome knowledge!! Looking forward to many other videos!
I'm sure there is some particular situation or LEDs where the shifter could potentially be an issue. But like you, I've done a lot of different installs with different LED types and have never experienced an issue with the I2C shifter (at least any that are visible to my eyes. Thanks for subscribing. I'm flattered that you've built or based so many of your projects on mine. I'm just happy that my videos are at least a little bit helpful to others. And thanks for taking time to leave a comment and share your experience with the I2C shifter.
Thanks for investigating this. I also opted for the I2C in combination with my electrocookie and I'm happy I don't seem to have made a mistake in doing that :)
No problem. I honestly didn't know if I would see a difference or not... and thought maybe I had missed out by using the I2C shifter on the couple of dozen LED installs I had done. I honestly expected to see a difference once the clock signal was introduced, but even then, it appears both shifters performed the same.
Thanks. Technically it is a green screen, but the image is from my actual bar that is just off to the right from where I actually shoot the videos. The actual area in front of the bar isn't really conducive to filming, although I do have a couple of older videos where I did record in front of the bar. I also have some really older videos with horrible backgrounds (and video/sound too). This was when I first started out and didn't have anything other than a laptop camera and microphone for recording. I've slowly invested in better equipment, lighting, etc. to try to make better looking videos. But those poorly done versions of my videos are still sitting out there... with hopefully helpful content even if the video and audio are subpar.
The thing to remember about the i2c level shifters is that there are several manufacturers who make them and they're not all the same (even if they look the same). Some will be fast enough and some won't depending on the values of the resistors and capacitors the manufacturer used. I have some cheap ones from Amazon that absolutely will not work with a ws2812b strip, but I've seen plenty of people use similar shifters without problems.
I would imagine that is true... like it is with most of these types of low cost components. I purchased a batch of 5 "low cost" ESP32s back in the day and 3 of those 5 wouldn't even power on and could not be flashed. I suppose I should consider myself fortunate that I haven't had any issues with any of the I2C shifters that I've bought... but I generally tend to stick with the same couple of sellers unless forced to change due to stock issues, etc. And I always breadboard test my components to be used before I create a final build. But you are correct that often corners are cut in the effort to save a tiny bit of money on a component and that can lead to problems for intended uses. As I found out with the ESP32s, you can even get some components that work and others that don't... even in the same shipment from the same vendor. Thanks for watching and taking the time to post a comment!
StephenHancock512: Yeah, I'm sure there's a quality difference between some manufacturers, but not a big difference in the "values of resisters and capacitors used" by any of the manufacturers! Remember, these are single-chip devices, not PCBs, so the size difference alone limits the sort of values that would make that kind of difference. I'm sure there may be differences in some of the trace sizes in the silicon, maybe even the depth and doping that would influence the rates of changes in conduction, resulting in speed differences. That would explain it to me, more so than differences in values of caps & resistors, lol. We'll just stick with quality difference.
I am sure there are many other things to consider here, but technically, the SN74HCT125N chip is a buffer, not a logic level shifter. The voltage in and out of the device is the same, 5 VDC in this case. What the buffer does is boost the signal drive current on the data line which, in turn, allows a longer distance to the first pixel by helping to overcome the data line resistance. Another difference is that the buffer allows data transmission in one direction. So, for an LED strip, either one can be used, but the buffer is probably the better choice. On an actual I2C bus, where the SDA line is actually bi-directional, you have to use the logic level shifter.
I think that the problem may appear with different leds strips, im using a 12v ws2811_400 using the fast led library on a esp32 and there are problems without doing some additional things like aadding a 470ohm resistor between the data output of hte level shifter and the data input of the led strip, anyway with that also some small artifacts. the shifter of the left in 2:22 is not an I2C device as Im aware of it.
I don't disagree... but it was impossible (and cost-prohibitive) for me to test every type of LED strip out there! I just know with my two dozen or so LED projects... mostly 5V WS2812b... I've not seen an issue with the I2C shifter. And just for the record, here is the listing for that shifter shown on the left, that indicates that it is an I2C device: amzn.to/43mi4rY
@@ResinChemTech well thats an amazon link not a datasheet, i think that device is only transistors it doesnt have an i2c address since theres not chip for that or necessity for connecting it to dedicated i2c pins like pins A4 and A5 of the arduino UNO for example, if you have the chance to test like you did on 12v strips it would be nice
I have learned so much from your videos... I can't thank you enough. trying to make my first wled controller had me beating my head off the wall until i found your videos. I can''t thank you enough. I actually printed and laminated your diagram so i always have a reference above my work area. Thanks a million for your time and dedication to these videos. Without them I surely would still be beating my head off the wall.
Thanks so much for the kind words! I do try to make my videos so that not only can someone follow along, but I also try to explain the "why" so that folks can take my ideas and concepts and maybe adapt to their own projects. This does tend to make my videos longer than "normal" other videos, but I try to include information I wish I would have known when I was first starting out. Thanks for watching... and again for taking time to post a comment.
Interesting video! Thanks! One thing I missed or it wasn't stated, The length of the data cable used. Back a few years ago, when I put up permanent ws2812b's on my eve's, My farthest eve (approx 55') had data issues with the DIY dig-uno I was using. I replaced that with a nodemcu and logic level shifter and it worked correctly, even with xlights running.
I kind of covered that a bit in my other video that determines if a logic level shifter is truly needed (or not). There isn't a hard and fast rule on a length of data cable that might cause issues. Variability in the tolerances of both the ESP, LED strips and the wiring itself means that a given data cable length might work fine without a shifter in some instances, but an exact same setup could have signal problems in another instance. That's why I always err on the side of caution and include a level shifter... even if my data cable length is only going to be a few inches long. The shifter costs about $1 and it only takes a few extra minutes of soldering to include it. By always including it, I don't have to worry about potential issues with the data signal, nor how long my data cable run might be (well, within reason!).
@ResinChemTech I would love to see you do this same thing with NO level shifter. Some of the newer WS2812b seems to work fine with a 3.3v signal. The other thing to include in the test, is the length of wire between the controller and the first LED. This is also an area where problems can occur, if this length gets too long, problems can happen. I always suggest keeping this distance below 12"/30cm but this doesn't work for every installation. BTW, after about 200 LEDs you shouldn't see any issues, the LEDs fix the signal after each chip, and the length is more about the OVERALL speed. Say you send a little faster than 800kbps (though the pulses are within spec on the low end) then at around 190th pixel there can be stutter. This issue took a bit of troubleshooting with the help a user to track down and fix (esp8266 issue). The fix was in NeoPixelBus in Feb 2023, the core library used to send the signals to the LEDS in WLED and other projects.
See this video, where I do what you are requesting: th-cam.com/video/Q9mLitVxF3c/w-d-xo.html As I said, you can often get away without the shifter.... until you can't. Adding a shifter just assures you don't have the problem with longer leads. But as with any DIY project, it is totally your call. I choose to always include the shifter... whether I could get away without it or not.
That is correct. Once the signal reaches the first LED, it is 'boosted' and passed on to the next LED on the strip. But if the signal that gets to that first pixel is 'jumbled'... say because the shifter really is causing an issue.. or naturally if the voltage drop is too great, it can cause all sorts of issues. As long as you get a good signal to that first LED (regardless of the method), then from a signal standpoint, all is good.
I built a controller to use with WS2811 bullet nodes and xLights. I have issues with the data integrity. Note, I built it with the I2C shifter you use and in testing all seemed to work well. It was after the distance increased between the controller and the first LED in the chain that I had an issue. I put a scope on the output of the I2C buffer and noticed the HV output was only at 3V for a logic level high. (I expected to see 5V) Later, I will wire up a replacement I2C buffer and check again. Maybe, I have a bad buffer. But in this scenario, I wonder if the little buffer has the ability to drive 4 separate outputs from 150 to 250 nodes each. I have ordered some 74AHCT125N chips to see if it makes any difference? Also, as a side note, for longer runs to the LEDs that you are using, have you tried to impedance match them for longer runs? What is the longest you have run from the WLED controller to the first LED in the chain? Joe
As stated in the video, I understand and agree that the 74AHCT125N is probably a better choice, but I personally haven't had any issues with the I2C-compatible shifters (I have used both types in my projects). I have run into a bad shifter a couple of times and I did hear from a few other folks that ones purchased from a particular vendor didn't work. But I'm not running large numbers of LEDs across multiple data pins. My biggest install is around 800 LEDs, but most are 400 or under. The only issue I've had is with a long data lead of around 15-20' where a single 3-wire cable was used (data line running in parallel with ground in the same cable). A 33 ohm resistor on the data line resolved that problem. Again, the buffer gate is the better choice (at least when looking under a scope), but I've never seen any "visible" difference or misbehaving LEDs with the I2C shifters.
The "I2C" shifter with only one Mosfet per channel switches with the transistor against GND and against plus with a pullup resistor. The one with the 74(A)HCTxx has a push pull output. The (A)dvanced is not needed at all because it is not that fast. You could also use a old 74LSxx. A 74HCxx is rather unfavorable, but could work. But you can only see the difference in the oscilloscope at the input of the first LED
Did you connect an oscilloscope to the input of the LED strip for each of the level shifter, 74`125, and bare signal? I did that and the level shifter output signal was horrible and not very square at all. The `125 also had a poor signal, but my chip was old and possibly bad. I initially took your advice a while back and used the simple level shifter, and had a 50 pixel ws2811 12v strand running Chase for a few hours around my window to the right of me ( in my peripheral vision) and every once in a while I would notice a strange flicker for an instant (which is what peripheral vision notices better). I removed the level shifter from the circuit and the flicker disappeared. Maybe my level shift was faulty, but I used the same one that was recommended and tried multiple ones. If needed, I can set up my tests again and capture scope traces.
No, I didn't try an oscilloscope. My purpose in the video was to see if there were any "real world" differences between the shifters when used in a average LED install, regardless of spec sheets or many claims that the I2C shifters were 'too slow'. I tried many different effects, colors and settings and could not produce a visible difference between the shifters. As I mentioned in the video, larger installations and/or different types of LED strips could result in a visible difference, but it wasn't possible (and cost-prohibitive) for me to test all the major types of LED strips out there. So I used a couple of types that would be the most common for the majority of people just getting started with LEDs. I haven't noticed any flicker with any of my over two dozen LED installs... all of which use a shifter (in most cases the I2C), including a few clocks that run 24/7, and I've never seen any flicker. I will occasionally see a quick 'hiccup' when changing from one effect to another or maybe when powering the LEDs off/on, but I haven't seen any flicker when just running an effect or pattern. That's been my experience anyway.
Please expound on "not very square". Is it rolloff, overshoot, or ringing? Rolloff is too much capacitance, not enough drive or both. Overshoot and/or ringing is too a fast rise time. A resistor between the -125 output and the LED string will improve that.
I prefer the SN74AHCT125N because it doesn't require me to run the 3.3V power to the IC. I have plenty of both kinds and agree with the conclusion in the video that the I2C type will work. Sometimes I need to tap the 3.3V anyway in which case it isn't much of an advantage to not need for it by the level shifter.
That is an advantage depending on the type of board you are building and the ESP you are using. But I had hoped to show that the I2C can work for most 'routine' installs and is just another option for a shifter. For beginners maybe building their first controller, I feel like the "SN74" and the pinouts can be a little more confusing and intimidating to try to solder (plus it simply won't fit on to the ElectroCookie mini with a D1 Mini... my favorite controller build due to its smaller size). I guess I had hope to either show that either could be used without a negative impact on the LED strip. Thanks for watching and taking time to post a comment!
@@ResinChemTech No problem. I enjoy your videos and they inspired me to try wled instead of just programming animations by hand in Python or C++ (or Rust). Now I have dozens of ESP32s with wled around the house. I was intimidated by the SN74AHCT125N when I first fell into the Maker rabbit hole, but now I use it on breadboards and perma-proto boards alike without hesitation.
Hello! I just got into this WLED thing and stumbled on your videos. You explain things very well! I've already bought the SN74 shifters. I wonder, will you make a video that shows the connections to that shifter? Also, another project that I'm having trouble understanding, and can't find a good explanation (in layman's terms) is how to use an esp and WLED to control a non-addressable LED strip. I've ordered mosfet boards and things as I've seen suggested but don't 100% understand how these work to make the controller work with non-addressable tape. Thank you so much!
If you find it helpful, I have a related blog article that shows a lot of standard wiring diagrams for WLED controllers. This article isn't really a how-to, but more of a listing of standard wiring diagrams, including one that shows how to wire the SN74x shifter to an ESP: resinchemtech.blogspot.com/2023/01/wiring-diagrams.html As far as non-addressable LEDs strips, to be honest I've never used or tried them. About the only recommendation I have for those are the official WLED site that does talk about using non-addressable LEDs and has a wiring diagram: kno.wled.ge/basics/compatible-led-strips/ I'd be happy to help you out more if I had any experience with these types of LED strips. Everything I've done with WLED up until this point has been with addressable LEDs. Sorry!
r @ResinChemTech Thank you very much! This blog is brilliant! Thank you for explaining things not like a smug electrical engineer. I will keep you posted on how I come with the non-addressable project! Take care.
Hi, first of all really nice videos on your channel. I have a question, in your wiring diagrams you have the pins 1, 4, 7 and 13, 12, 10, 9 to ground in this diagram (SN74AHCT25N Shifter), but if I look at the WLED site I see that pin 1, 4, 7, 12 and 9 to ground and 13 and 10 to +5volt and the use a 100nF capacitor and on the data pins a 62 - 100 ohm resistor. so i wonder which diagram is correct? I hope you can help. Thanks in advance
From what I can tell (assuming I'm looking at the same diagrams), they are technically both correct and will work. The SN74AHCT125 has up to four data channels. For something like WS2812b LED strips, you are only going to use one of those. In my case, I'm pulling the unused channels to ground and in the WLED diagram, they are pulling those pins high (5V). I'm not 100% sure whether pulling them to ground (low) or 5V (high) really makes any difference, other than that they are not left "floating". As far as the capacitor and resistor, I've found them to be optional in *most* cases. There has been one situation where I needed to add a resistor to a long data line run that was in parallel to the ground wire. The capacitor is just there to "even out" the voltage. You can certainly add the resistor and capacitor, but in most cases I tried to build the most basic controller that I can since my channel tends to target those new to DIY electronics. I used to add a capacitor to all my controllers, but have omitted it in my last dozen or so builds with no ill effects. For the "purest" signal and voltage, you can add either/or... but again, I've found they are generally not needed... especially on smaller LED projects. But YMMV so it is ultimately up to you to decide if you want them or not.
@@ResinChemTechah that was what I thought but not 100% sure, I need 2 data pins so the other 2 will go to ground. Just ordered Al the stuf combined with a btf fcob ws2811 24v Thanks for your reply 😊
maybe.. sound reactivity? I'm thinking of the esp32 vs. 8266 discrepancy and it occurs to me you might try it in that context and if it complicates your premise (no visible delta) either redo the video or just tack on an addendum.. IF there is a difference that is, i have no idea.
Glad I could help out. I've had many debates about the suitability of the I2C-compatible shifter. And while technically "on paper", the buffer gate shifter is the better choice, I've never observed any difference... or had any issues.. with the I2C-compatible shifter. Nor have I seen anyone show an actual visible difference with the LEDs... I'm not talking about a line on an oscilloscope, but something I can see with my eyes with the LEDs. But as always... the choice is up to the individual to decide what is best for their project.
good day Sir 👋 I'm curious about the difference between logic level shifter and shift register. I'm new about this and don't have any idea of those 😅 can you make a video explaining the difference between logic level shifter and shift register and their uses on the led panel, strips and matrix.
Regardless of the method or type of chip used, the intent is to shift the logic level of 3.3V from the ESP GPIO pin to the 5V logic level expected by the LED strip for the data signal. Both the standard logic level shifter and certain shift registers accomplish the same task, but in slightly different ways. As I stated in this video, many people "claim" that the standard I2C-compatible shifter is "too slow" for LED usage and you should use something like the SN74AHCT125N. But as I showed in this video (and through over two dozen LED installs that I've done), I've never been able to visibly see any issues with using the actual logic level shifter. But in a nutshell, both serve the same purpose of converting the 3.3V logic signal to a 5V logic signal. Hope that helps, but if you want more info, try a simple search for "Logic Level vs. Shift Register".
Seems that the timing depends on how the I2C unit is made, meaning if they are push pull or open drain (with open drain being the slowest) then the I2C style level shifter would be 40-60 Mbps vs 2 Mbps and also the timing has a lot to play here too as the I2C style can be anywhere from (push pull) 16.7 ns to (open drain) 500 ns. Where the SN74 style timing is 6.5 ns to 8.5 ns depending on the load capacitance, I couldn't find anything about speed with the SN74. So with all of that the SN74 is 2 times as fast as the I2C style level shifter. Also, 8 ns isn't some thing at we can perceive with the naked eye. So like you mentioned and I agree is that the longer the string of leds or maybe even the quantity (like 144/meter vs 60/meter) may start giving odd results.
Its not about visual speed of switching on or off leds, the problem with a shifter that is to slow is that the digital signal doesn't process all binary data... Not giving you a slower led-transition, but from a certain point the strip will interpet the binary data wrong, probably turning off the strip, making it flicker or turning to a single color...
hey i'm assuming that in this video, the ElectroCookie Solderable Breadboards that you were using were the 1/2 sized ones right? really cool 3D printed cases you have there--would you mind sharing the .stl file that you used to print out the case for the breadboard/controller? thanks!
For this particular video, I was using the full size ElectroCookie board. I prefer to use the 1/2 size, but with the full size ESP32 and the length of the SN74 shifter, it would not fit on the 1/2 size. You can find my .stl files for the enclosures here: www.thingiverse.com/thing:4969733 It includes versions for both the full and 1/2 size, with some variations for things like the end openings and mounting tabs. Just FYI, the post mounting holes for the board are based on M2 x 6 or M2 x 8 screws.
My enclosures are for these two size ElectroCookie boards: amzn.to/44LFgS4 I used the larger of those two sizes for this video, but often use the mini size when using a D1 Mini and I2C shifter. If you are looking for a different size ElectroCookie board, I haven't used it... and therefore don't have an enclosure designed for it. But these designs were just done in TinkerCad... and they are pretty basic and easy to create, so you can probably adapt one of my designs for a different size board.
@@ResinChemTech ah i see. my apologies for the confusion. i got thrown off by the cookie board saying “1/2 sized breadboard” for the big one and 1/4 for the little one it’s on the bottom of the board in faded text we’re cool! thanks again
Hello. I love your work. I do have a question. If im using an ESP32 board, am i able to use multiple channels out of the ESP to multiple channels of the same logic level shifter? Or should each channel get its own shifter? And what channels of the ESP should i use? Thank you
Yes, you can use a single shifter. The I2C-compatible shifters have 4 channels, labeled LV1-LV4 on the low side and HV1-HV4 on the high side. This means that you can shift up to four signals with a single shifter. The SN74AHCT125N is also a quad gate buffer with I believe up to four input/output channels. As far as which pins to use, on the ESP32 it pretty much doesn't matter. But you can see more about using multiple pins on the ESP32 with WLED on the official WLED web site here: kno.wled.ge/features/multi-strip/
Thank you for the reply!! I also have another question. As far as cable length. From the ESP to the logic level shifter to the first led, is there a max cable length? Would you be able to add another logic shifter down the line as an amplifier of sorts?
The max length would be whenever the voltage drops too low to provide a reliable signal. I know that's not much of an answer, but it depends upon a number of factors... the type and gauge wire being used for one... among other factors, so there isn't a 'set length' that could be stated as a max. But yes, you could add a "booster" on a long run or in situations where you might have a long run between two consecutive strips (like if adding to your house outdoors and you have a long wiring span where one strip ends and where the next one begins). But remember that the shifters require voltage and ground lines as well, so you'd have to get power to the shifter as well. If you need to boost a signal along the line somewhere, you may want to consider taking a look at Quindor's data booster. I've used this in one of my installs and it works well: quinled.info/quinled-data-booster-for-sale/
I just built a new controller for 12v lights and with the i2c level shifters it would not work past a 2 foot extension cable I removed the shifter and it worked just fine
I'm new to all this. What if I want to use more than one data pin with the SN74AHCT25N? Looking at your diagram on BlogSpot (I won't be using a clock pin on my setup), you have 1A, and 2A as input and 1Y and 2Y as output with the 1C and 2C as grounds. Can I assume the same is all true for 3A, 3B, 3Y, etc.? This leads me to ask can this chip then handle total of 4 control lines and is that recommended? I have a 2904 LED matrix I'm building (six panels with 484 LEDs each). I'm thinking about using 6 control pins on an ESP32 (484 LED's per pin). Can I add another SN74AHCT25N for the other two? Hope this makes sense. The LED's are WS281B's BTW. Thank you for your great videos and blogposts!
The SN74AHCT125N is a quad gate buffer... so yes, you should be able to run four data lines. I connected the unused lines to ground just to assure they weren't left in a floating state... probably not necessary, but it doesn't hurt. While I haven't tried it myself, I believe you should be able to use two shifters to shift more data lines. The biggest thing is to assure everything is using a common ground so you don't end up with ground potential differences. But please follow up and let me know if you were successful in using multiple shifters. I haven't done any LED projects large enough to require that many data pins, so I'll be curious as to how yours works out. Best of luck!
@@ResinChemTech Thank you for the quick reply! This is a large LED project and I might be over my head a bit. I'll need three power supplies (60A each), and when you say common ground do you mean I need to connect all the grounds together using a terminal strip?
Yeah... everything needs to be tied to a common ground.... but especially the controller and the LEDs. If there is a ground potential difference between the controller and LEDs, the LEDs will very likely behave strangely with flickering, wrong colors, etc. Best of luck with your project!
I'm still collecting parts for my installation. There's no way to beat the fact that it's several feet from my MCU to the LED strip, so I decided I probably need a buffer. I was considering the sacrificial pixel method when I realized that the buffer was needed mostly because the MCU is 3.3V and probably a wimpy driver to boot. It occurred to me (independently) that something from the 74HCT family would do the trick. HCT inputs expect 0-2V signals and put out 0-5V. I selected the 74HCT244 because I had some. I recognized that the 74HCT125 did essentially the same thing, but only had 4 buffers. The -125 has independent TS enables whereas the -244 has 2 banks of 4. But we're not going to TS them anyway, so that doesn't matter. I think ANY buffer (I2C, 125, 244 etc will work, IF the rise and fall times are good enough not to distort the waveform. Any difference in buffer delay is also irrelevant so long as it's consistent. Remember, the data is delayed at EVERY pixel as the signals propagate from one to the next. If you were to put a scope on DI at the first pixel, and a second trace at DO on the last pixel, there would be a considerable lag, perhaps so much that the two wouldn't even look alike. If a -125 works, my -244 should too.
I would be really curious what kind of results you get with WS2814 RGBW strips. I have the 24 volt variation from BTF lighting, and I cannot for the life of me get them to work correctly using an I2C shifter. I'm doing some testing using an Arduino which is 5 volts for its digital outputs (so no level shifter needed) and it works perfectly everytime. I'm guessing since they have the extra color, white, they must use a higher frequency protocol which is above what the I2C shifter can handle. It's the SK6812 protocol.
While I do not have, nor have I tried, WS2814 24V, I have successfully used SK6812 (5V) with the I2C shifter successfully. You did not mention what firmware you are using, but as a test, I'd try connecting to the LEDs from the controller without the shifter (using a short wiring run) using the exact same firmware/settings and see if the LEDs behave normally. If you can try this on a breadboard, you can easily try the same setup with the shifter, then just bypass the shifter to see if there are any differences. Does the strip work normally when using a SN74x shifter? If it does work with this shifter, that would confirm that it is I2C related. I'm not saying that the I2C shifter isn't the problem, but I am simply unable to test every possible type and voltage of LED strip out there... but I've yet to run into a situation where the I2C shifter has caused an issue. Let me know what you find.
@@ResinChemTech thanks for the reply. I believe I'm using firmware 0.14.0-b1 but I'm not currently where I can check for certain. I was able to get some "glitchy" results with and without the I2C shifter while using short jumpers and a bread board but nothing very consistent. I have a prebuilt ESP based LED controller on order which includes a built in shifter (not sure which chip yet) so I'm hoping that will work. I will let you know the results!
I find these level shifters difficult to understand. I always thought a level shifter (for example) could convert a 3.3v signal to a 5v signal. But now I understand that this is not the case at all with the SN74AHCT125 because it has no voltage translation. Suddenly I don't see the point of having an SN74AHCT125. I also saw that someone is selling a booster board that has a SN74LVC2G34DBVR on it as a level shifter that is fed with 5 volts. But if I understand the datasheet correctly then this level shifter should not work at all because with a vcc of 5 volts the active high should then be 3.5v. Am I now completely on the wrong path and understanding it all wrong?
I am not an electrical engineer, so I can't provide you with the actual specifics. But the simple explanation as I understand it is that the SN74AHCT125 series have a 5 volt supply connected. It then takes the 3.3V input data line and "shifts" the output of that data line to the supplied 5V. You can find multiple examples online that describe the exact scenario of using this component to 'shift' a 3.3V signal to 5V. And as I showed in another video ( th-cam.com/video/Q9mLitVxF3c/w-d-xo.html ) when you have a long data line and the voltage drops too low due to resistance.. and the LEDs start to misbehave... use of a logic level shifter immediately fixes the issue by boosting the voltage on that data line. All I can tell you is that most reliable sources (including the official WLED web site: kno.wled.ge/basics/compatible-hardware/ - see the section under level shifters) recommend use of a logic level shifter... particularly when you have a longer data line length between the controller and start of the LEDs. And many of those same sources state that the SN74AHCT125 series are the 'recommended' shifters... even though as I have found and showed in this video that an I2C shifter appears to work equally well in most cases. Again, I don't have the engineering background to describe the "how"... just that I found that they do work.
The general idea is that 5v TTL logic high level is typically 2v or above, so the input of 3.3v will be considered high and the logic circuit will output 5v.
@@ResinChemTech - I am an old retired engineer, and grew up with these. The 74HCT series came out during the transition period between TTL and CMOS devices. It is powered with 5V, and the CMOS outputs swing from very near 0V to very near 5V. Level "shifter" is not really the correct description for what these parts do. There is a 74HC series that is CMOS inputs and outputs. The HCT family ACCEPTS TTL level input signals. Anything above 2V is considered a '1'. Anything below 0.7V is considered a '0'. So even a 3.3V signal meets these criteria and "boosts" a weak signal to a strong 5V signal. The LEDs EXPECT a 5V signal. They have trouble deciding what's a '1' and what's a '0' when it receives a weak signal. The flickering is a result of the signal being misinterpreted.
For the controllers? I 3D printed those, but you can find the design files here on Thingiverse: www.thingiverse.com/thing:4969733 Note that the Thingiverse project has designs for both the mini and full size ElectroCookie boards (I used the full size in this video), plus some other variation for things like mounting tabs, different end openings, etc.
My main issue with the 74AHCT125 buffer is the pinout for the most part; while it's handy to only need to input 5 volts into the chip to make it work, I've abandoned it in place of the TXS0108E chip in my own personal projects away from WLED as routing PCBs is far easier.
Yeah, the TXS08108, much like the I2C, is a bit easier to deal with in my opinion... especially for those just starting out. I think the "SN74" is nice if you like to socket your components, but when soldering onto a prototype board, I feel the I2C/TXS08x styles are a bit easier and more straightforward for the beginner. Thanks for taking time to post a comment!
Don't get me wrong, I enjoy your videos, however... 1. The 74 was visibly brighter in your video 2. Clocked strips would actually negate the timing issue, since the data and clock would be slowed the same amount 3. Not sure where you're getting your chips, but the 74AHCT125N from digikey is $0.58 or less, depending on quantity... Not $4.00
I am by no means an expert... and I was actually expecting to see some sort of difference. But I don't believe the signal (or shifter) would have anything to do with brightness. If one strip appeared brighter, it was likely either the camera angle (LED are hard to film in the first place, so I had the brightness way down... to like 15% or so.. and I don't necessarily have the highest quality camera) or possibly slight differences in the brightness settings in WLED. Voltage differences could also impact brightness, but both has the same size power supply/injection points. I didn't notice any significant brightness difference when looking at the strips when I was testing/filming. I think the point I was trying to make is that both strips acted identically with either shifter. At least for these strips and 300 LEDs each, I could not see nor even create any situation where there was any true visible difference in performance between the two.... clock signal or not. Yeah... you are right about the cost. I ordered a 4 pack of the SN74 that was $16 (on Amazon, but the same place where I got 10 I2C for less than $10). I'm sure that shopping around could have resulted in a better price. But those were the prices I paid for this particular project. Thanks for the feedback and thoughts.
While I do use Home Assistant and feature it in a lot of my other videos, what you are seeing in this video is WLED. WLED runs on the ESP32 and is used to control LED lights. But WLED does have a native integration into Home Assistant, so the LEDs can also be controlled from there as well. Thanks for watching.
I feel like I'm spamming your videos with comments these days... Just saw another video about level shifters from you yesterday and now this... Good to see.. I will stick with the regular level shifter 👍 .. But one question if OK... What is that box you use? Lookes really neat with the board in and fits in the boxes... Is it some you 3D printed or can you get them from somewhere? .. Thanks again for yet an awesome video.... I also have my own channel but not very big... I am thinking on "giving you an answer" of my result in a video to see if the level shifter will solve my problem here... am thinking on buying a 15 pack of level shifter from amazon in Germany (we don't have amazon here in Denmark) .. but I have though an "electronic shop" in Copenhagen where they have level shifters at home... But 1 of those there costs the same as like maybe 10 in amazon funny
No problem on the comments... and I'm always happy to try to answer any questions. I generally use the I2C-compatible shifter but will occasionally use the SN74x shifter for things like matrix displays, since I bought a number of them to create this video. But again, I've never seen any performance difference that I can detect with my eyes. Those boxes are 3D printed enclosures that I designed. If you have access to a 3D printer, you can find the design files here: www.thingiverse.com/thing:4969733 There are designs for both the full size and mini ElectroCookie boards, which is what I use for most of my WLED controllers. But you can also find small electronic project boxes that are similar in size and pretty easy to drill and modify to make them work as an enclosure... which is what I did prior to getting my 3D printer.
Yeah... I opted to do this video because so many people had told me that the I2C shifter was "too slow", despite the fact I have used it in dozen of installs. I had actually expected to see a difference when the clock signal was introduced... but no matter what I tried, I could not 'force' any differences to be visible between the shifters. At least not with only 300 LEDs. I do suspect a matrix or large install might see some differences... but I'm not even 100% sure in that case. Thanks for adding your experiences.
You are actually correct. These are not I2C devices, but are compatible with I2C devices since they are bi-directional and multi-channel, allowing the signal to be shifted both up and down. They should technically be called I2C-compatible shifters, but are pretty much always just labeled and referred to as I2C shifters.
maybe the main reason people see issues is if their home wiring isnt giving them the right voltage, so any power transformers may not be giving the right voltage too.
That's a possibility, but I always check the output of my power supply to assure the correct voltage before connecting any components. And the larger power supplies have adjustment potentiometers that allow you to tweak the voltage output to the precise value expected. But I'm not sure that everyone checks the output of their power supply before use and may just assume it is outputting the expected voltage. Most of the components used in these types of projects have a operating range voltage and rarely will a 0.1V or 0.2V variance have much of an impact, if any. Thanks for the comment... the improper voltage can definitely cause issues in some situations.
hola soy de argentina ya llevo poco mas de 2 años con esto de los pixeles y por lo que veo el problema siempre comienza desp de los 800 pixeles aveces mas otras menos perodesp de los 900 siempre tengo problemas de señal parpadeo ect
Thanks for this video. I was hoping that you'd have the chance to hang an oscilloscope on the output lines. Yeah, that smacks right up there with analyzing specs! I've been fighting this for the past few days, and the results were "inconclusive". (A cardiologist ran some tests on me some time ago, and also said the results were "inconclusive". Must be a medical term, but not a great confidence builder.) Anyway, I didn't notice any difference between using the I2C shifter and not using any shifter; both behaviors were problematic. The board was very sensitive to hand or finger positioning near or on the data line. I did some more fiddling, and ended up with some components placed differently, though electrically identical to the first way. Now it works much better, but is still very sensitive to minor nearby disturbances. I haven't had a chance to use the SN74 part yet; it's on order. The electrical difference between the 2 level shifters is that the SN74 has push-pull outputs, thus driving the output to the desired level, but the I2C component outputs are open-drain, relying on a 10k resistor to pull the data line to the high level. Hence my desire to see the outputs on a 'scope. Thanks again. I've enjoyed many of your videos; they are so clear and helpful. Keep up the great work!
That's interesting. I've never had any issues with sensitivity of the data line.. with one exception. I have an install with a very long run (~15 ft) between the controller and start of the LEDs. I used a single cable with 3 wires for that run. Having the data line in the same cable as the ground for a long run can cause issues. However, this was resolved in my case with a 33 ohm resistor installed on the data line. Other than that, I've not had any issues with interference on the data line. I actually just tested one of my installs and wrapped my hand around the data line at different points and did not notice any impact on the signal. I'm not sure what might be going on, but you might try a larger gauge wire... that's about the only recommendation I can make other than maybe trying a resistor on the data line.
People that claim they can tell a visual difference in viewing something operating in megahertz r parroting what they read online. I see this I2C argument often, and the only way you notice a visual difference is w/ components like displays (you're correct on the matrixes, but they'd have to be pretty detailed) I highly doubt anyone is going to notice on something like LEDs. You're far more patient than I lol
I completely agree with you, but I had received so many comments saying (or parroting as you better describe) that I2C shifters were "too slow", some going as far as quoting me specs, that I decided just to do this video to try to put the issue to rest. I've used both and I've never seen any 'performance' difference or issues on any of my LED installs... including multiple matrices and a linear install of over 800 LEDs. It is possible, I suppose, that some cheap clones might cause issues... or as you say, you could see it with very large installs or matrices. But I got tired of trying to respond to all the comments, and regardless of what the 'spec sheet' says, I've never been able to detect any 'speed' issues with the I2C shifters. But as I always say, it's _your_ DIY project. If you want to use a different shifter (or not use one at all), feel free to do so. (Sorry for the ramble, but as you can probably tell, I've had the argument so many times it tends to get me a bit rankled at time). Regardless, I appreciate your comment... and the time you took to leave it.
@@ResinChemTech -- No worries -- I appreciate it. Not many channels communicate as much. It lets us see your view on how the stuff works and I find that helpful. Especially when i was new to this all. I give you a lot of credit for just doing the experiment though. It really was the best way to address it. B/c I could see how dozens of people might say the same thing, not realizing someone else before them said it. It seems to be the nature of this style of social media though. People impulsively give that first thought response, which can be both good and bad 😆 Either way -- I love the content. I'm constantly soldering and building sensors and LED strips in my spare time, trying to build upon my HomeAsst setup. And Ive learned a lot from your channel 👍
Now you know, since everybody thinks they're an electronics engineer, someone is going to say there is a difference in your controller boards because their different colors! LOL
Ain't that the truth! I have never claimed to be an electrical engineer and I try to take concepts and reduce them down to both something that a non-engineer can understand and more importantly, how it might (or might not) impact a project. That was my point here... does it really matter if the "leading edge of the signal under an oscilloscope at a given frequency rises at a slower rate" if you can't see the difference with your eyes and the LEDS work as expected? But anytime I do anything with a logic level shifter it brings out all the so-called "experts" that want to quote specifications and data sheets or tell me that they ran a 30 foot data lead with no shifter at all. Fine... use the shifter of your choice or don't use one at all. It's your project. I simply try to share what I've found in my own projects and builds, with the hope that it might help out someone else who is just starting or learning. Am I an expert in anything? Absolutely not. Is everything I say always 100% accurate? Of course not. But everything I show or explain IS based on my personal experience and projects. For those that think they know better, I'd encourage them to pick up a web cam, start making TH-cam videos and show everyone the "right" way! Thank you so much for the comment! I really did make me laugh this morning. And it is comments like yours that encourage me to keep making videos... despite some of the other comments.
@ResinChemTech I watch and like your videos, so keep your chin up and contribute to the community. I had a weird issue on a couple of projects when I switched to a ESP32 that I never had with an ESP8266. I have had either to run a small project led strip at 3.3v same as 3.3v pin or use a level shifter to get the signal up to 5v to run the Leds at 5v. Guys on the Wled forum said it was the ESP32 I was using, but it wasn't. So anytime I use a ESP32 and want the leds at 5v then I use a level shifter to get the signal up to 5v.
No idea why anyone calls them.I2C but they have nothing to do with the I2C bus. And abbreveating the IC to SN74 makes little sens, thats the family name.better 74125 or ’125
I believe that they have commonly been called I2C because they are I2C-compatible, not because they are I2C devices. You are correct , and they should probably be labeled that way, but they are commonly just listed as "I2C Level Shifters" and that's the way many places, sites and other sources (including the official WLED web site) refer to them... correct or not. And I just used "SN74" as an abbreviation in the video because the full "SN74AHCT125N" was just too much of a mouthful to keep repeating. My goal was to simply differentiate between the "I2C-compatible style" and what I guess I should have referred to as the "74125-family" of shifters. My bad and I apologize if my terminology led to some sort of confusion between the two styles of shifters.
hey man i've got a huge favor to ask--how in the world do you wire up the SN74 shifter to a LED controller board? i'm really new at this and was just watching the video you put out recentlyabout how to build your first LED controller (th-cam.com/video/dXLOqGa-n5A/w-d-xo.html). it was INCREDIBLY helpful. thank you for that--because of you, i was able to successfully pull it off in setting up a HyperHDR LED controller. your videos are incredibly approachable to people new at this and i just wanted you to know how much i appreciate you and the work you've put into trying to teach others how to get started. so, onto my question: I've been spending some time on HyperHDR's github and the dev is insisting that a SN74 needs to be used as the level logic shifter to avoid problems, but i haven't been able to find any documentation on how to built a board using that particular shifter. I was able to do it using an I2C linked in your previous video but I'd also like to build one using the 'faster' SN74--i just don't know how. would you be able to point me to an easy-to-follow resource for me to look at and understand how it's supposed to be done? the wiring diagrams that you drew on your site (resinchemtech.blogspot.com/2023/01/wiring-diagrams.html) are super easy to follow and would really appreciate it if you could draw one up for the SN74AHCT125N. again, thanks so much. you're brilliant and really appreciated--please keep up the good work. i don't just speak for myself when saying that you're one of the best educators on youtube on this stuff
Check that blog article again. When I published this video, I added diagrams, including a wiring diagram for the SN74 shifter. You can find it under a new section called "Logic Level Shifters".
That's primarily because this is a follow-up video to the original, where I do show what can happen without a shifter and when the signal voltage drops too low: th-cam.com/video/Q9mLitVxF3c/w-d-xo.html The purpose of this video was to show a comparison to the two shifter options if you DO opt to include one (which I personally recommend). Yes, you can sometimes get away without one... and sometimes it causes issues, as I show in the original video. But this video's intent was to compare any visible differences between two different shifter types... and not to compare shifter vs. no shifter... which I had already done in that earlier video.
Thanks! Just trying to show that there are always options in DIY projects. And while specs are important (especially ones related to safety... like amp ratings that shouldn't be ignored), specs aren't always the full story. Even the omission of a level shifter is a testament to that fact. Theoretically, the LEDs shouldn't work with a signal voltage below 3.2-3.5V, but obviously in most cases they will still work fine. This is just another example of where the specs may indicate that an I2C shifter is "too slow", but it works perfectly well in most normal LED installations. Thanks for watching... and the kind comment.
dude this couldn’t have come at a better time. subscribed
I used the I2C shifter you recommended on my Christmas tree. 21 strands totaling 1050 leds and it works great.
Outstanding! That's a ton of LEDs... I bet the tree looks great! My WLED Christmas tree is now in its third year of use and still going strong.
Thanks for taking a moment to comment and share what you found when using the I2C shifter.
Thanks for sharing good information
I am a sub'r to your channel and have watched many of your videos and replicated many of your cookie board set ups from motion sensor triggered hallway lighting to WLED general setup lighting and have used the same WS2812 LEDs, I2C logic level shifters, ESP boards and everything else you've used/recommended and have had PERFECT results every time. I have had absolutely ZERO issues with the logic level shifter. I was doing some testing about a year ago and put 4 rolls of 300 WS2812 LED lights (TOTAL OF 1200 LEDS) using the ESP board and the logic level shifter and also a few power injection points in a few different areas and had the same brightness on LED number 1200 as I had on LED number 1. Also there was absolutely ZERO issues with what people are claiming when it comes to hesitation, delay, flickering and whatnot. The data channel was in flawless working order. That's my 2 cents about these wonderful logic level shifters. I will never have a LED project WITHOUT the I2C logic level shifter. Thanks for the video and sharing all of your awesome knowledge!! Looking forward to many other videos!
I'm sure there is some particular situation or LEDs where the shifter could potentially be an issue. But like you, I've done a lot of different installs with different LED types and have never experienced an issue with the I2C shifter (at least any that are visible to my eyes.
Thanks for subscribing. I'm flattered that you've built or based so many of your projects on mine. I'm just happy that my videos are at least a little bit helpful to others. And thanks for taking time to leave a comment and share your experience with the I2C shifter.
Thanks for investigating this. I also opted for the I2C in combination with my electrocookie and I'm happy I don't seem to have made a mistake in doing that :)
No problem. I honestly didn't know if I would see a difference or not... and thought maybe I had missed out by using the I2C shifter on the couple of dozen LED installs I had done. I honestly expected to see a difference once the clock signal was introduced, but even then, it appears both shifters performed the same.
Great video, but do you plan on making a video with a long distance of the data cable and the two different level shifters?
You are the first person I see having a nice background like that...normally its solder stations and oscilloscopes...
Thanks. Technically it is a green screen, but the image is from my actual bar that is just off to the right from where I actually shoot the videos. The actual area in front of the bar isn't really conducive to filming, although I do have a couple of older videos where I did record in front of the bar.
I also have some really older videos with horrible backgrounds (and video/sound too). This was when I first started out and didn't have anything other than a laptop camera and microphone for recording. I've slowly invested in better equipment, lighting, etc. to try to make better looking videos. But those poorly done versions of my videos are still sitting out there... with hopefully helpful content even if the video and audio are subpar.
I will definitely check those out :) @@ResinChemTech
The thing to remember about the i2c level shifters is that there are several manufacturers who make them and they're not all the same (even if they look the same). Some will be fast enough and some won't depending on the values of the resistors and capacitors the manufacturer used. I have some cheap ones from Amazon that absolutely will not work with a ws2812b strip, but I've seen plenty of people use similar shifters without problems.
I would imagine that is true... like it is with most of these types of low cost components. I purchased a batch of 5 "low cost" ESP32s back in the day and 3 of those 5 wouldn't even power on and could not be flashed. I suppose I should consider myself fortunate that I haven't had any issues with any of the I2C shifters that I've bought... but I generally tend to stick with the same couple of sellers unless forced to change due to stock issues, etc. And I always breadboard test my components to be used before I create a final build. But you are correct that often corners are cut in the effort to save a tiny bit of money on a component and that can lead to problems for intended uses. As I found out with the ESP32s, you can even get some components that work and others that don't... even in the same shipment from the same vendor.
Thanks for watching and taking the time to post a comment!
Same experience here. Some work great, some don't'.
StephenHancock512:
Yeah, I'm sure there's a quality difference between some manufacturers, but not a big difference in the "values of resisters and capacitors used" by any of the manufacturers!
Remember, these are single-chip devices, not PCBs, so the size difference alone limits the sort of values that would make that kind of difference.
I'm sure there may be differences in some of the trace sizes in the silicon, maybe even the depth and doping that would influence the rates of changes in conduction, resulting in speed differences.
That would explain it to me, more so than differences in values of caps & resistors, lol.
We'll just stick with quality difference.
I am sure there are many other things to consider here, but technically, the SN74HCT125N chip is a buffer, not a logic level shifter. The voltage in and out of the device is the same, 5 VDC in this case. What the buffer does is boost the signal drive current on the data line which, in turn, allows a longer distance to the first pixel by helping to overcome the data line resistance. Another difference is that the buffer allows data transmission in one direction. So, for an LED strip, either one can be used, but the buffer is probably the better choice. On an actual I2C bus, where the SDA line is actually bi-directional, you have to use the logic level shifter.
I think that the problem may appear with different leds strips, im using a 12v ws2811_400 using the fast led library on a esp32 and there are problems without doing some additional things like aadding a 470ohm resistor between the data output of hte level shifter and the data input of the led strip, anyway with that also some small artifacts. the shifter of the left in 2:22 is not an I2C device as Im aware of it.
I don't disagree... but it was impossible (and cost-prohibitive) for me to test every type of LED strip out there! I just know with my two dozen or so LED projects... mostly 5V WS2812b... I've not seen an issue with the I2C shifter. And just for the record, here is the listing for that shifter shown on the left, that indicates that it is an I2C device: amzn.to/43mi4rY
@@ResinChemTech well thats an amazon link not a datasheet, i think that device is only transistors it doesnt have an i2c address since theres not chip for that or necessity for connecting it to dedicated i2c pins like pins A4 and A5 of the arduino UNO for example, if you have the chance to test like you did on 12v strips it would be nice
@@artesalve3233 It's for I2C logic signals, not as an I2C device. There is no reason for it to have an address as it should be transparent.
I have learned so much from your videos... I can't thank you enough. trying to make my first wled controller had me beating my head off the wall until i found your videos. I can''t thank you enough. I actually printed and laminated your diagram so i always have a reference above my work area. Thanks a million for your time and dedication to these videos. Without them I surely would still be beating my head off the wall.
Thanks so much for the kind words! I do try to make my videos so that not only can someone follow along, but I also try to explain the "why" so that folks can take my ideas and concepts and maybe adapt to their own projects. This does tend to make my videos longer than "normal" other videos, but I try to include information I wish I would have known when I was first starting out.
Thanks for watching... and again for taking time to post a comment.
Interesting video! Thanks! One thing I missed or it wasn't stated, The length of the data cable used. Back a few years ago, when I put up permanent ws2812b's on my eve's, My farthest eve (approx 55') had data issues with the DIY dig-uno I was using. I replaced that with a nodemcu and logic level shifter and it worked correctly, even with xlights running.
I kind of covered that a bit in my other video that determines if a logic level shifter is truly needed (or not). There isn't a hard and fast rule on a length of data cable that might cause issues. Variability in the tolerances of both the ESP, LED strips and the wiring itself means that a given data cable length might work fine without a shifter in some instances, but an exact same setup could have signal problems in another instance.
That's why I always err on the side of caution and include a level shifter... even if my data cable length is only going to be a few inches long. The shifter costs about $1 and it only takes a few extra minutes of soldering to include it. By always including it, I don't have to worry about potential issues with the data signal, nor how long my data cable run might be (well, within reason!).
thanks for testing!
@ResinChemTech I would love to see you do this same thing with NO level shifter. Some of the newer WS2812b seems to work fine with a 3.3v signal.
The other thing to include in the test, is the length of wire between the controller and the first LED. This is also an area where problems can occur, if this length gets too long, problems can happen. I always suggest keeping this distance below 12"/30cm but this doesn't work for every installation.
BTW, after about 200 LEDs you shouldn't see any issues, the LEDs fix the signal after each chip, and the length is more about the OVERALL speed. Say you send a little faster than 800kbps (though the pulses are within spec on the low end) then at around 190th pixel there can be stutter. This issue took a bit of troubleshooting with the help a user to track down and fix (esp8266 issue). The fix was in NeoPixelBus in Feb 2023, the core library used to send the signals to the LEDS in WLED and other projects.
See this video, where I do what you are requesting: th-cam.com/video/Q9mLitVxF3c/w-d-xo.html
As I said, you can often get away without the shifter.... until you can't. Adding a shifter just assures you don't have the problem with longer leads. But as with any DIY project, it is totally your call. I choose to always include the shifter... whether I could get away without it or not.
Nice work. Thanks!
Doesn't the shifter only matter up to the first LED? After that, the LED controller takes over, kind of like using the dead pixel method.
That is correct. Once the signal reaches the first LED, it is 'boosted' and passed on to the next LED on the strip. But if the signal that gets to that first pixel is 'jumbled'... say because the shifter really is causing an issue.. or naturally if the voltage drop is too great, it can cause all sorts of issues. As long as you get a good signal to that first LED (regardless of the method), then from a signal standpoint, all is good.
I2C shifter is not working on my ws2811 pixel. For example, when I try to transition a pixel from black to white, it flickers red.
I built a controller to use with WS2811 bullet nodes and xLights. I have issues with the data integrity. Note, I built it with the I2C shifter you use and in testing all seemed to work well. It was after the distance increased between the controller and the first LED in the chain that I had an issue. I put a scope on the output of the I2C buffer and noticed the HV output was only at 3V for a logic level high. (I expected to see 5V) Later, I will wire up a replacement I2C buffer and check again. Maybe, I have a bad buffer. But in this scenario, I wonder if the little buffer has the ability to drive 4 separate outputs from 150 to 250 nodes each. I have ordered some 74AHCT125N chips to see if it makes any difference? Also, as a side note, for longer runs to the LEDs that you are using, have you tried to impedance match them for longer runs? What is the longest you have run from the WLED controller to the first LED in the chain?
Joe
As stated in the video, I understand and agree that the 74AHCT125N is probably a better choice, but I personally haven't had any issues with the I2C-compatible shifters (I have used both types in my projects). I have run into a bad shifter a couple of times and I did hear from a few other folks that ones purchased from a particular vendor didn't work. But I'm not running large numbers of LEDs across multiple data pins. My biggest install is around 800 LEDs, but most are 400 or under. The only issue I've had is with a long data lead of around 15-20' where a single 3-wire cable was used (data line running in parallel with ground in the same cable). A 33 ohm resistor on the data line resolved that problem.
Again, the buffer gate is the better choice (at least when looking under a scope), but I've never seen any "visible" difference or misbehaving LEDs with the I2C shifters.
@@ResinChemTech Thank you sir, for taking the time to answer my question.
The "I2C" shifter with only one Mosfet per channel switches with the transistor against GND and against plus with a pullup resistor.
The one with the 74(A)HCTxx has a push pull output. The (A)dvanced is not needed at all because it is not that fast. You could also use a old 74LSxx. A 74HCxx is rather unfavorable, but could work.
But you can only see the difference in the oscilloscope at the input of the first LED
Did you connect an oscilloscope to the input of the LED strip for each of the level shifter, 74`125, and bare signal? I did that and the level shifter output signal was horrible and not very square at all. The `125 also had a poor signal, but my chip was old and possibly bad. I initially took your advice a while back and used the simple level shifter, and had a 50 pixel ws2811 12v strand running Chase for a few hours around my window to the right of me ( in my peripheral vision) and every once in a while I would notice a strange flicker for an instant (which is what peripheral vision notices better). I removed the level shifter from the circuit and the flicker disappeared. Maybe my level shift was faulty, but I used the same one that was recommended and tried multiple ones. If needed, I can set up my tests again and capture scope traces.
No, I didn't try an oscilloscope. My purpose in the video was to see if there were any "real world" differences between the shifters when used in a average LED install, regardless of spec sheets or many claims that the I2C shifters were 'too slow'. I tried many different effects, colors and settings and could not produce a visible difference between the shifters. As I mentioned in the video, larger installations and/or different types of LED strips could result in a visible difference, but it wasn't possible (and cost-prohibitive) for me to test all the major types of LED strips out there. So I used a couple of types that would be the most common for the majority of people just getting started with LEDs.
I haven't noticed any flicker with any of my over two dozen LED installs... all of which use a shifter (in most cases the I2C), including a few clocks that run 24/7, and I've never seen any flicker. I will occasionally see a quick 'hiccup' when changing from one effect to another or maybe when powering the LEDs off/on, but I haven't seen any flicker when just running an effect or pattern. That's been my experience anyway.
Please expound on "not very square". Is it rolloff, overshoot, or ringing? Rolloff is too much capacitance, not enough drive or both. Overshoot and/or ringing is too a fast rise time. A resistor between the -125 output and the LED string will improve that.
Perfect demo Sir - thx
I prefer the SN74AHCT125N because it doesn't require me to run the 3.3V power to the IC. I have plenty of both kinds and agree with the conclusion in the video that the I2C type will work. Sometimes I need to tap the 3.3V anyway in which case it isn't much of an advantage to not need for it by the level shifter.
That is an advantage depending on the type of board you are building and the ESP you are using. But I had hoped to show that the I2C can work for most 'routine' installs and is just another option for a shifter. For beginners maybe building their first controller, I feel like the "SN74" and the pinouts can be a little more confusing and intimidating to try to solder (plus it simply won't fit on to the ElectroCookie mini with a D1 Mini... my favorite controller build due to its smaller size). I guess I had hope to either show that either could be used without a negative impact on the LED strip.
Thanks for watching and taking time to post a comment!
@@ResinChemTech No problem. I enjoy your videos and they inspired me to try wled instead of just programming animations by hand in Python or C++ (or Rust). Now I have dozens of ESP32s with wled around the house. I was intimidated by the SN74AHCT125N when I first fell into the Maker rabbit hole, but now I use it on breadboards and perma-proto boards alike without hesitation.
Hello! I just got into this WLED thing and stumbled on your videos. You explain things very well! I've already bought the SN74 shifters. I wonder, will you make a video that shows the connections to that shifter? Also, another project that I'm having trouble understanding, and can't find a good explanation (in layman's terms) is how to use an esp and WLED to control a non-addressable LED strip. I've ordered mosfet boards and things as I've seen suggested but don't 100% understand how these work to make the controller work with non-addressable tape. Thank you so much!
If you find it helpful, I have a related blog article that shows a lot of standard wiring diagrams for WLED controllers. This article isn't really a how-to, but more of a listing of standard wiring diagrams, including one that shows how to wire the SN74x shifter to an ESP: resinchemtech.blogspot.com/2023/01/wiring-diagrams.html
As far as non-addressable LEDs strips, to be honest I've never used or tried them. About the only recommendation I have for those are the official WLED site that does talk about using non-addressable LEDs and has a wiring diagram: kno.wled.ge/basics/compatible-led-strips/ I'd be happy to help you out more if I had any experience with these types of LED strips. Everything I've done with WLED up until this point has been with addressable LEDs. Sorry!
r @ResinChemTech Thank you very much! This blog is brilliant! Thank you for explaining things not like a smug electrical engineer. I will keep you posted on how I come with the non-addressable project! Take care.
Hi, first of all really nice videos on your channel. I have a question, in your wiring diagrams you have the pins 1, 4, 7 and 13, 12, 10, 9 to ground in this diagram (SN74AHCT25N Shifter), but if I look at the WLED site I see that pin 1, 4, 7, 12 and 9 to ground and 13 and 10 to +5volt and the use a 100nF capacitor and on the data pins a 62 - 100 ohm resistor. so i wonder which diagram is correct? I hope you can help. Thanks in advance
From what I can tell (assuming I'm looking at the same diagrams), they are technically both correct and will work. The SN74AHCT125 has up to four data channels. For something like WS2812b LED strips, you are only going to use one of those. In my case, I'm pulling the unused channels to ground and in the WLED diagram, they are pulling those pins high (5V). I'm not 100% sure whether pulling them to ground (low) or 5V (high) really makes any difference, other than that they are not left "floating".
As far as the capacitor and resistor, I've found them to be optional in *most* cases. There has been one situation where I needed to add a resistor to a long data line run that was in parallel to the ground wire. The capacitor is just there to "even out" the voltage. You can certainly add the resistor and capacitor, but in most cases I tried to build the most basic controller that I can since my channel tends to target those new to DIY electronics. I used to add a capacitor to all my controllers, but have omitted it in my last dozen or so builds with no ill effects. For the "purest" signal and voltage, you can add either/or... but again, I've found they are generally not needed... especially on smaller LED projects. But YMMV so it is ultimately up to you to decide if you want them or not.
@@ResinChemTechah that was what I thought but not 100% sure, I need 2 data pins so the other 2 will go to ground. Just ordered Al the stuf combined with a btf fcob ws2811 24v
Thanks for your reply 😊
I just subbed and this is my first video to watch ❤
Welcome! I hope you find my content to be helpful in your own projects.
maybe.. sound reactivity? I'm thinking of the esp32 vs. 8266 discrepancy and it occurs to me you might try it in that context and if it complicates your premise (no visible delta) either redo the video or just tack on an addendum.. IF there is a difference that is, i have no idea.
Again you saved me again with another video ❤thanks 😂
Glad I could help out. I've had many debates about the suitability of the I2C-compatible shifter. And while technically "on paper", the buffer gate shifter is the better choice, I've never observed any difference... or had any issues.. with the I2C-compatible shifter. Nor have I seen anyone show an actual visible difference with the LEDs... I'm not talking about a line on an oscilloscope, but something I can see with my eyes with the LEDs. But as always... the choice is up to the individual to decide what is best for their project.
good day Sir 👋
I'm curious about the difference between logic level shifter and shift register.
I'm new about this and don't have any idea of those 😅 can you make a video explaining the difference between logic level shifter and shift register and their uses on the led panel, strips and matrix.
Regardless of the method or type of chip used, the intent is to shift the logic level of 3.3V from the ESP GPIO pin to the 5V logic level expected by the LED strip for the data signal.
Both the standard logic level shifter and certain shift registers accomplish the same task, but in slightly different ways. As I stated in this video, many people "claim" that the standard I2C-compatible shifter is "too slow" for LED usage and you should use something like the SN74AHCT125N. But as I showed in this video (and through over two dozen LED installs that I've done), I've never been able to visibly see any issues with using the actual logic level shifter.
But in a nutshell, both serve the same purpose of converting the 3.3V logic signal to a 5V logic signal. Hope that helps, but if you want more info, try a simple search for "Logic Level vs. Shift Register".
Seems that the timing depends on how the I2C unit is made, meaning if they are push pull or open drain (with open drain being the slowest) then the I2C style level shifter would be 40-60 Mbps vs 2 Mbps and also the timing has a lot to play here too as the I2C style can be anywhere from (push pull) 16.7 ns to (open drain) 500 ns. Where the SN74 style timing is 6.5 ns to 8.5 ns depending on the load capacitance, I couldn't find anything about speed with the SN74. So with all of that the SN74 is 2 times as fast as the I2C style level shifter. Also, 8 ns isn't some thing at we can perceive with the naked eye. So like you mentioned and I agree is that the longer the string of leds or maybe even the quantity (like 144/meter vs 60/meter) may start giving odd results.
Its not about visual speed of switching on or off leds, the problem with a shifter that is to slow is that the digital signal doesn't process all binary data...
Not giving you a slower led-transition, but from a certain point the strip will interpet the binary data wrong, probably turning off the strip, making it flicker or turning to a single color...
How about music effects - like ledFX ?
hey i'm assuming that in this video, the ElectroCookie Solderable Breadboards that you were using were the 1/2 sized ones right? really cool 3D printed cases you have there--would you mind sharing the .stl file that you used to print out the case for the breadboard/controller? thanks!
For this particular video, I was using the full size ElectroCookie board. I prefer to use the 1/2 size, but with the full size ESP32 and the length of the SN74 shifter, it would not fit on the 1/2 size.
You can find my .stl files for the enclosures here: www.thingiverse.com/thing:4969733 It includes versions for both the full and 1/2 size, with some variations for things like the end openings and mounting tabs. Just FYI, the post mounting holes for the board are based on M2 x 6 or M2 x 8 screws.
@@ResinChemTech amazing. thank you so much
@@ResinChemTech so i'm seeing the full and mini, but not a file suggesting that they're for a 1/2 size--am i missing something?
My enclosures are for these two size ElectroCookie boards: amzn.to/44LFgS4
I used the larger of those two sizes for this video, but often use the mini size when using a D1 Mini and I2C shifter. If you are looking for a different size ElectroCookie board, I haven't used it... and therefore don't have an enclosure designed for it. But these designs were just done in TinkerCad... and they are pretty basic and easy to create, so you can probably adapt one of my designs for a different size board.
@@ResinChemTech ah i see. my apologies for the confusion. i got thrown off by the cookie board saying “1/2 sized breadboard” for the big one and 1/4 for the little one
it’s on the bottom of the board in faded text
we’re cool! thanks again
Hello. I love your work. I do have a question. If im using an ESP32 board, am i able to use multiple channels out of the ESP to multiple channels of the same logic level shifter? Or should each channel get its own shifter? And what channels of the ESP should i use? Thank you
Yes, you can use a single shifter. The I2C-compatible shifters have 4 channels, labeled LV1-LV4 on the low side and HV1-HV4 on the high side. This means that you can shift up to four signals with a single shifter. The SN74AHCT125N is also a quad gate buffer with I believe up to four input/output channels.
As far as which pins to use, on the ESP32 it pretty much doesn't matter. But you can see more about using multiple pins on the ESP32 with WLED on the official WLED web site here: kno.wled.ge/features/multi-strip/
Thank you for the reply!! I also have another question. As far as cable length. From the ESP to the logic level shifter to the first led, is there a max cable length? Would you be able to add another logic shifter down the line as an amplifier of sorts?
The max length would be whenever the voltage drops too low to provide a reliable signal. I know that's not much of an answer, but it depends upon a number of factors... the type and gauge wire being used for one... among other factors, so there isn't a 'set length' that could be stated as a max. But yes, you could add a "booster" on a long run or in situations where you might have a long run between two consecutive strips (like if adding to your house outdoors and you have a long wiring span where one strip ends and where the next one begins). But remember that the shifters require voltage and ground lines as well, so you'd have to get power to the shifter as well.
If you need to boost a signal along the line somewhere, you may want to consider taking a look at Quindor's data booster. I've used this in one of my installs and it works well: quinled.info/quinled-data-booster-for-sale/
I just built a new controller for 12v lights and with the i2c level shifters it would not work past a 2 foot extension cable I removed the shifter and it worked just fine
I'm new to all this. What if I want to use more than one data pin with the SN74AHCT25N? Looking at your diagram on BlogSpot (I won't be using a clock pin on my setup), you have 1A, and 2A as input and 1Y and 2Y as output with the 1C and 2C as grounds. Can I assume the same is all true for 3A, 3B, 3Y, etc.? This leads me to ask can this chip then handle total of 4 control lines and is that recommended? I have a 2904 LED matrix I'm building (six panels with 484 LEDs each). I'm thinking about using 6 control pins on an ESP32 (484 LED's per pin). Can I add another SN74AHCT25N for the other two? Hope this makes sense. The LED's are WS281B's BTW.
Thank you for your great videos and blogposts!
The SN74AHCT125N is a quad gate buffer... so yes, you should be able to run four data lines. I connected the unused lines to ground just to assure they weren't left in a floating state... probably not necessary, but it doesn't hurt. While I haven't tried it myself, I believe you should be able to use two shifters to shift more data lines. The biggest thing is to assure everything is using a common ground so you don't end up with ground potential differences.
But please follow up and let me know if you were successful in using multiple shifters. I haven't done any LED projects large enough to require that many data pins, so I'll be curious as to how yours works out. Best of luck!
@@ResinChemTech Thank you for the quick reply! This is a large LED project and I might be over my head a bit. I'll need three power supplies (60A each), and when you say common ground do you mean I need to connect all the grounds together using a terminal strip?
Yeah... everything needs to be tied to a common ground.... but especially the controller and the LEDs. If there is a ground potential difference between the controller and LEDs, the LEDs will very likely behave strangely with flickering, wrong colors, etc.
Best of luck with your project!
Thanks so much! Apparently I do have a small clue. I’ll keep you posted. Thank you the great information.
I'm still collecting parts for my installation. There's no way to beat the fact that it's several feet from my MCU to the LED strip, so I decided I probably need a buffer. I was considering the sacrificial pixel method when I realized that the buffer was needed mostly because the MCU is 3.3V and probably a wimpy driver to boot. It occurred to me (independently) that something from the 74HCT family would do the trick. HCT inputs expect 0-2V signals and put out 0-5V. I selected the 74HCT244 because I had some. I recognized that the 74HCT125 did essentially the same thing, but only had 4 buffers. The -125 has independent TS enables whereas the -244 has 2 banks of 4. But we're not going to TS them anyway, so that doesn't matter.
I think ANY buffer (I2C, 125, 244 etc will work, IF the rise and fall times are good enough not to distort the waveform. Any difference in buffer delay is also irrelevant so long as it's consistent. Remember, the data is delayed at EVERY pixel as the signals propagate from one to the next. If you were to put a scope on DI at the first pixel, and a second trace at DO on the last pixel, there would be a considerable lag, perhaps so much that the two wouldn't even look alike. If a -125 works, my -244 should too.
I would be really curious what kind of results you get with WS2814 RGBW strips. I have the 24 volt variation from BTF lighting, and I cannot for the life of me get them to work correctly using an I2C shifter. I'm doing some testing using an Arduino which is 5 volts for its digital outputs (so no level shifter needed) and it works perfectly everytime. I'm guessing since they have the extra color, white, they must use a higher frequency protocol which is above what the I2C shifter can handle. It's the SK6812 protocol.
While I do not have, nor have I tried, WS2814 24V, I have successfully used SK6812 (5V) with the I2C shifter successfully. You did not mention what firmware you are using, but as a test, I'd try connecting to the LEDs from the controller without the shifter (using a short wiring run) using the exact same firmware/settings and see if the LEDs behave normally. If you can try this on a breadboard, you can easily try the same setup with the shifter, then just bypass the shifter to see if there are any differences. Does the strip work normally when using a SN74x shifter? If it does work with this shifter, that would confirm that it is I2C related.
I'm not saying that the I2C shifter isn't the problem, but I am simply unable to test every possible type and voltage of LED strip out there... but I've yet to run into a situation where the I2C shifter has caused an issue. Let me know what you find.
@@ResinChemTech thanks for the reply. I believe I'm using firmware 0.14.0-b1 but I'm not currently where I can check for certain. I was able to get some "glitchy" results with and without the I2C shifter while using short jumpers and a bread board but nothing very consistent. I have a prebuilt ESP based LED controller on order which includes a built in shifter (not sure which chip yet) so I'm hoping that will work. I will let you know the results!
I find these level shifters difficult to understand. I always thought a level shifter (for example) could convert a 3.3v signal to a 5v signal. But now I understand that this is not the case at all with the SN74AHCT125 because it has no voltage translation. Suddenly I don't see the point of having an SN74AHCT125. I also saw that someone is selling a booster board that has a SN74LVC2G34DBVR on it as a level shifter that is fed with 5 volts. But if I understand the datasheet correctly then this level shifter should not work at all because with a vcc of 5 volts the active high should then be 3.5v. Am I now completely on the wrong path and understanding it all wrong?
I am not an electrical engineer, so I can't provide you with the actual specifics. But the simple explanation as I understand it is that the SN74AHCT125 series have a 5 volt supply connected. It then takes the 3.3V input data line and "shifts" the output of that data line to the supplied 5V. You can find multiple examples online that describe the exact scenario of using this component to 'shift' a 3.3V signal to 5V.
And as I showed in another video ( th-cam.com/video/Q9mLitVxF3c/w-d-xo.html ) when you have a long data line and the voltage drops too low due to resistance.. and the LEDs start to misbehave... use of a logic level shifter immediately fixes the issue by boosting the voltage on that data line.
All I can tell you is that most reliable sources (including the official WLED web site: kno.wled.ge/basics/compatible-hardware/ - see the section under level shifters) recommend use of a logic level shifter... particularly when you have a longer data line length between the controller and start of the LEDs. And many of those same sources state that the SN74AHCT125 series are the 'recommended' shifters... even though as I have found and showed in this video that an I2C shifter appears to work equally well in most cases. Again, I don't have the engineering background to describe the "how"... just that I found that they do work.
@@ResinChemTech No problem, I will continue my research :-) Anyway thanks for your comprehensive response!!!
The general idea is that 5v TTL logic high level is typically 2v or above, so the input of 3.3v will be considered high and the logic circuit will output 5v.
@@ResinChemTech - I am an old retired engineer, and grew up with these. The 74HCT series came out during the transition period between TTL and CMOS devices. It is powered with 5V, and the CMOS outputs swing from very near 0V to very near 5V. Level "shifter" is not really the correct description for what these parts do. There is a 74HC series that is CMOS inputs and outputs. The HCT family ACCEPTS TTL level input signals. Anything above 2V is considered a '1'. Anything below 0.7V is considered a '0'. So even a 3.3V signal meets these criteria and "boosts" a weak signal to a strong 5V signal. The LEDs EXPECT a 5V signal. They have trouble deciding what's a '1' and what's a '0' when it receives a weak signal. The flickering is a result of the signal being misinterpreted.
Do you have a link to the project box you were using?
For the controllers? I 3D printed those, but you can find the design files here on Thingiverse: www.thingiverse.com/thing:4969733
Note that the Thingiverse project has designs for both the mini and full size ElectroCookie boards (I used the full size in this video), plus some other variation for things like mounting tabs, different end openings, etc.
My main issue with the 74AHCT125 buffer is the pinout for the most part; while it's handy to only need to input 5 volts into the chip to make it work, I've abandoned it in place of the TXS0108E chip in my own personal projects away from WLED as routing PCBs is far easier.
Yeah, the TXS08108, much like the I2C, is a bit easier to deal with in my opinion... especially for those just starting out. I think the "SN74" is nice if you like to socket your components, but when soldering onto a prototype board, I feel the I2C/TXS08x styles are a bit easier and more straightforward for the beginner.
Thanks for taking time to post a comment!
Don't get me wrong, I enjoy your videos, however...
1. The 74 was visibly brighter in your video
2. Clocked strips would actually negate the timing issue, since the data and clock would be slowed the same amount
3. Not sure where you're getting your chips, but the 74AHCT125N from digikey is $0.58 or less, depending on quantity... Not $4.00
I am by no means an expert... and I was actually expecting to see some sort of difference. But I don't believe the signal (or shifter) would have anything to do with brightness. If one strip appeared brighter, it was likely either the camera angle (LED are hard to film in the first place, so I had the brightness way down... to like 15% or so.. and I don't necessarily have the highest quality camera) or possibly slight differences in the brightness settings in WLED. Voltage differences could also impact brightness, but both has the same size power supply/injection points. I didn't notice any significant brightness difference when looking at the strips when I was testing/filming.
I think the point I was trying to make is that both strips acted identically with either shifter. At least for these strips and 300 LEDs each, I could not see nor even create any situation where there was any true visible difference in performance between the two.... clock signal or not.
Yeah... you are right about the cost. I ordered a 4 pack of the SN74 that was $16 (on Amazon, but the same place where I got 10 I2C for less than $10). I'm sure that shopping around could have resulted in a better price. But those were the prices I paid for this particular project.
Thanks for the feedback and thoughts.
Thank you.
cool! That looks like Home assistant but I not sure
While I do use Home Assistant and feature it in a lot of my other videos, what you are seeing in this video is WLED. WLED runs on the ESP32 and is used to control LED lights. But WLED does have a native integration into Home Assistant, so the LEDs can also be controlled from there as well.
Thanks for watching.
cool...thanks I am sure gonna check that out hehehe....
If you need a faster response for some obscure application, replace the 10k resistors with 1k.
I feel like I'm spamming your videos with comments these days... Just saw another video about level shifters from you yesterday and now this... Good to see.. I will stick with the regular level shifter 👍 .. But one question if OK... What is that box you use? Lookes really neat with the board in and fits in the boxes... Is it some you 3D printed or can you get them from somewhere? .. Thanks again for yet an awesome video.... I also have my own channel but not very big... I am thinking on "giving you an answer" of my result in a video to see if the level shifter will solve my problem here... am thinking on buying a 15 pack of level shifter from amazon in Germany (we don't have amazon here in Denmark) .. but I have though an "electronic shop" in Copenhagen where they have level shifters at home... But 1 of those there costs the same as like maybe 10 in amazon funny
No problem on the comments... and I'm always happy to try to answer any questions. I generally use the I2C-compatible shifter but will occasionally use the SN74x shifter for things like matrix displays, since I bought a number of them to create this video.
But again, I've never seen any performance difference that I can detect with my eyes.
Those boxes are 3D printed enclosures that I designed. If you have access to a 3D printer, you can find the design files here: www.thingiverse.com/thing:4969733 There are designs for both the full size and mini ElectroCookie boards, which is what I use for most of my WLED controllers. But you can also find small electronic project boxes that are similar in size and pretty easy to drill and modify to make them work as an enclosure... which is what I did prior to getting my 3D printer.
There is a lot of 12C stuff that works even even out of spec. I use it for all kinds of stuff, even long distances.
Yeah... I opted to do this video because so many people had told me that the I2C shifter was "too slow", despite the fact I have used it in dozen of installs. I had actually expected to see a difference when the clock signal was introduced... but no matter what I tried, I could not 'force' any differences to be visible between the shifters. At least not with only 300 LEDs. I do suspect a matrix or large install might see some differences... but I'm not even 100% sure in that case.
Thanks for adding your experiences.
Incidentally, the term is not "jitteriness," or "jittery," it's just "jitter."
Otherwise, good video, fair test.
Thanks!
Покажи пожалуйста как подключить переключатели (правильное подключение пины схема.)
Схемы подключения вы можете найти здесь: resinchemtech.blogspot.com/2023/01/wiring-diagrams.html
@@ResinChemTech а есть видео где показывается жертвенный пиксель как сделать и чем он хуже того что вы показывали на видео?
Это не хуже, это просто другой путь. У меня нет видео, показывающего жертвенный пиксель. Извини.
@@ResinChemTech спасибо
@@ResinChemTech я вроде на вашем форуме (сайте нашел как это сделать) это же у вас там есть виде схемы я правильно понял?)
I am going to embarrass myself, but here goes. Why is the I2C called that? There is no address, like 078 required. What am I missing?
You are actually correct. These are not I2C devices, but are compatible with I2C devices since they are bi-directional and multi-channel, allowing the signal to be shifted both up and down. They should technically be called I2C-compatible shifters, but are pretty much always just labeled and referred to as I2C shifters.
maybe the main reason people see issues is if their home wiring isnt giving them the right voltage, so any power transformers may not be giving the right voltage too.
That's a possibility, but I always check the output of my power supply to assure the correct voltage before connecting any components. And the larger power supplies have adjustment potentiometers that allow you to tweak the voltage output to the precise value expected.
But I'm not sure that everyone checks the output of their power supply before use and may just assume it is outputting the expected voltage. Most of the components used in these types of projects have a operating range voltage and rarely will a 0.1V or 0.2V variance have much of an impact, if any.
Thanks for the comment... the improper voltage can definitely cause issues in some situations.
hola soy de argentina ya llevo poco mas de 2 años con esto de los pixeles y por lo que veo el problema siempre comienza desp de los 800 pixeles aveces mas otras menos perodesp de los 900 siempre tengo problemas de señal parpadeo ect
Thanks for this video. I was hoping that you'd have the chance to hang an oscilloscope on the output lines. Yeah, that smacks right up there with analyzing specs! I've been fighting this for the past few days, and the results were "inconclusive". (A cardiologist ran some tests on me some time ago, and also said the results were "inconclusive". Must be a medical term, but not a great confidence builder.) Anyway, I didn't notice any difference between using the I2C shifter and not using any shifter; both behaviors were problematic. The board was very sensitive to hand or finger positioning near or on the data line. I did some more fiddling, and ended up with some components placed differently, though electrically identical to the first way. Now it works much better, but is still very sensitive to minor nearby disturbances. I haven't had a chance to use the SN74 part yet; it's on order. The electrical difference between the 2 level shifters is that the SN74 has push-pull outputs, thus driving the output to the desired level, but the I2C component outputs are open-drain, relying on a 10k resistor to pull the data line to the high level. Hence my desire to see the outputs on a 'scope.
Thanks again. I've enjoyed many of your videos; they are so clear and helpful. Keep up the great work!
That's interesting. I've never had any issues with sensitivity of the data line.. with one exception. I have an install with a very long run (~15 ft) between the controller and start of the LEDs. I used a single cable with 3 wires for that run. Having the data line in the same cable as the ground for a long run can cause issues. However, this was resolved in my case with a 33 ohm resistor installed on the data line.
Other than that, I've not had any issues with interference on the data line. I actually just tested one of my installs and wrapped my hand around the data line at different points and did not notice any impact on the signal. I'm not sure what might be going on, but you might try a larger gauge wire... that's about the only recommendation I can make other than maybe trying a resistor on the data line.
People that claim they can tell a visual difference in viewing something operating in megahertz r parroting what they read online.
I see this I2C argument often, and the only way you notice a visual difference is w/ components like displays (you're correct on the matrixes, but they'd have to be pretty detailed)
I highly doubt anyone is going to notice on something like LEDs.
You're far more patient than I lol
I completely agree with you, but I had received so many comments saying (or parroting as you better describe) that I2C shifters were "too slow", some going as far as quoting me specs, that I decided just to do this video to try to put the issue to rest.
I've used both and I've never seen any 'performance' difference or issues on any of my LED installs... including multiple matrices and a linear install of over 800 LEDs. It is possible, I suppose, that some cheap clones might cause issues... or as you say, you could see it with very large installs or matrices. But I got tired of trying to respond to all the comments, and regardless of what the 'spec sheet' says, I've never been able to detect any 'speed' issues with the I2C shifters. But as I always say, it's _your_ DIY project. If you want to use a different shifter (or not use one at all), feel free to do so.
(Sorry for the ramble, but as you can probably tell, I've had the argument so many times it tends to get me a bit rankled at time). Regardless, I appreciate your comment... and the time you took to leave it.
@@ResinChemTech -- No worries -- I appreciate it. Not many channels communicate as much. It lets us see your view on how the stuff works and I find that helpful. Especially when i was new to this all.
I give you a lot of credit for just doing the experiment though. It really was the best way to address it. B/c I could see how dozens of people might say the same thing, not realizing someone else before them said it.
It seems to be the nature of this style of social media though. People impulsively give that first thought response, which can be both good and bad 😆
Either way -- I love the content. I'm constantly soldering and building sensors and LED strips in my spare time, trying to build upon my HomeAsst setup. And Ive learned a lot from your channel 👍
Now you know, since everybody thinks they're an electronics engineer, someone is going to say there is a difference in your controller boards because their different colors! LOL
Ain't that the truth! I have never claimed to be an electrical engineer and I try to take concepts and reduce them down to both something that a non-engineer can understand and more importantly, how it might (or might not) impact a project. That was my point here... does it really matter if the "leading edge of the signal under an oscilloscope at a given frequency rises at a slower rate" if you can't see the difference with your eyes and the LEDS work as expected?
But anytime I do anything with a logic level shifter it brings out all the so-called "experts" that want to quote specifications and data sheets or tell me that they ran a 30 foot data lead with no shifter at all. Fine... use the shifter of your choice or don't use one at all. It's your project. I simply try to share what I've found in my own projects and builds, with the hope that it might help out someone else who is just starting or learning. Am I an expert in anything? Absolutely not. Is everything I say always 100% accurate? Of course not. But everything I show or explain IS based on my personal experience and projects. For those that think they know better, I'd encourage them to pick up a web cam, start making TH-cam videos and show everyone the "right" way!
Thank you so much for the comment! I really did make me laugh this morning. And it is comments like yours that encourage me to keep making videos... despite some of the other comments.
@ResinChemTech I watch and like your videos, so keep your chin up and contribute to the community. I had a weird issue on a couple of projects when I switched to a ESP32 that I never had with an ESP8266. I have had either to run a small project led strip at 3.3v same as 3.3v pin or use a level shifter to get the signal up to 5v to run the Leds at 5v. Guys on the Wled forum said it was the ESP32 I was using, but it wasn't. So anytime I use a ESP32 and want the leds at 5v then I use a level shifter to get the signal up to 5v.
No idea why anyone calls them.I2C but they have nothing to do with the I2C bus. And abbreveating the IC to SN74 makes little sens, thats the family name.better 74125 or ’125
I believe that they have commonly been called I2C because they are I2C-compatible, not because they are I2C devices. You are correct , and they should probably be labeled that way, but they are commonly just listed as "I2C Level Shifters" and that's the way many places, sites and other sources (including the official WLED web site) refer to them... correct or not.
And I just used "SN74" as an abbreviation in the video because the full "SN74AHCT125N" was just too much of a mouthful to keep repeating. My goal was to simply differentiate between the "I2C-compatible style" and what I guess I should have referred to as the "74125-family" of shifters. My bad and I apologize if my terminology led to some sort of confusion between the two styles of shifters.
hey man i've got a huge favor to ask--how in the world do you wire up the SN74 shifter to a LED controller board?
i'm really new at this and was just watching the video you put out recentlyabout how to build your first LED controller (th-cam.com/video/dXLOqGa-n5A/w-d-xo.html). it was INCREDIBLY helpful. thank you for that--because of you, i was able to successfully pull it off in setting up a HyperHDR LED controller. your videos are incredibly approachable to people new at this and i just wanted you to know how much i appreciate you and the work you've put into trying to teach others how to get started.
so, onto my question: I've been spending some time on HyperHDR's github and the dev is insisting that a SN74 needs to be used as the level logic shifter to avoid problems, but i haven't been able to find any documentation on how to built a board using that particular shifter. I was able to do it using an I2C linked in your previous video but I'd also like to build one using the 'faster' SN74--i just don't know how.
would you be able to point me to an easy-to-follow resource for me to look at and understand how it's supposed to be done? the wiring diagrams that you drew on your site (resinchemtech.blogspot.com/2023/01/wiring-diagrams.html) are super easy to follow and would really appreciate it if you could draw one up for the SN74AHCT125N.
again, thanks so much. you're brilliant and really appreciated--please keep up the good work. i don't just speak for myself when saying that you're one of the best educators on youtube on this stuff
Check that blog article again. When I published this video, I added diagrams, including a wiring diagram for the SN74 shifter. You can find it under a new section called "Logic Level Shifters".
@@ResinChemTech got it. thank you again
You had no control set to see what happens with no level shifter whatsoever.
That's primarily because this is a follow-up video to the original, where I do show what can happen without a shifter and when the signal voltage drops too low: th-cam.com/video/Q9mLitVxF3c/w-d-xo.html
The purpose of this video was to show a comparison to the two shifter options if you DO opt to include one (which I personally recommend). Yes, you can sometimes get away without one... and sometimes it causes issues, as I show in the original video. But this video's intent was to compare any visible differences between two different shifter types... and not to compare shifter vs. no shifter... which I had already done in that earlier video.
Testing and it worked means nothing!! if you want to design a reliable system respect to specification.
Good lesson for today.
Thanks! Just trying to show that there are always options in DIY projects. And while specs are important (especially ones related to safety... like amp ratings that shouldn't be ignored), specs aren't always the full story. Even the omission of a level shifter is a testament to that fact. Theoretically, the LEDs shouldn't work with a signal voltage below 3.2-3.5V, but obviously in most cases they will still work fine.
This is just another example of where the specs may indicate that an I2C shifter is "too slow", but it works perfectly well in most normal LED installations.
Thanks for watching... and the kind comment.
@@ResinChemTech good lesson comes good teacher.