when i desolder filled holes I find it easier to heat it the pad from one side and have the solder sucker at the opposite end of the hole. of course you will need a vice to hold the board in place. thanks for the video...very helpful
+bd594 Yep, always been doing it this way. Piece of cake. If you can't (because the "other side" is not accessible), solder wick is an easy enough solution.
That's really weird you should mention nuclear power plants - I was thinking of the Simpsons episode when Homer tries to use the phone and gets a message saying "the fingers with which you have dialled are too fat, if you require operator assistance, mash the keypad with your fist now" Edit- Just to clarify - I'm not referring to Julian here or being cruel - I wouldn't be able to press these on their own either. It's just what I think of when buttons are too small for adult fingers.
Julian Ilett In order to avoid blocking the text on the PCB, you could have soldered in the headers on the component side, then remove the plastic bases.
Back in 1975 - a 4000 series logic chip with a 10 Meg resistor between input and ground - produced a reliable touch sensitive switch. Picking up mains hum when touched.
I think the toggle behavior we see at the end is when someone would be inputting a 4 digit pin. push to lock in and move onto the next char, when all 4 are entered deselect all to get ready for next input combination. Could be worthwhile looking at the serial output/I2C and analyze how it sends the input as entered.
Have got the TTP224 board here. Just had a look and the numbers are filed off the chip !!! Wanted to see if any other details were there, such as manuf date for a 'bad batch' thought.
I know, it's quite late and I don't know if already said it... Through hole pads are easier to clean if you put the "sucker" on one side of the pcb and the soldering iron on the opposite side. And a little dip of flux (or fresh flux containing solder) can help a lot as well. Hope this is helpful anyways. Greetings from Germany!
Julian Ilett With those filled in-holes, I'd either use the heat gun, heat it up and just push the headers in without bothering to suck out the solder, or I'd blob a load of solder all over it, heat it with the soldering iron and just poke the pins through one by one with the solder molten, then just suck or wick away the excess solder. In other words, don't bother trying to get the solder out of the holes, just worry about getting the pins in :)
Also, I'm wondering if those touch pads are actually intended to be extended in some really botchy way, ie by capacitively coupling a wire on to them without making an electrical connection. I'm wondering what happens if you just physically stick a wire to each pad with glue or tape and then touch the end of it? Or perhaps a small square of conductive foil glued to each pad with a wire attached?
Looks like having too many LEDs lit up is causing the chip to shut down. I wonder if the output pins on the chip are driven off the internal voltage regualtor - I imagine that can only handle a few mA. Cheers!!
Yes, an output pin can only source 4mA according to the datasheet. But it does not mention what the limit for all of them is and if it's driven off the regulator. Julian Ilett measure the voltage at the output pins, preferably with an oscilloscope, and check for "dips". The internal regulator has 2.3V so if you see that, you know the LEDs are driven from it. Btw. you have to specifically search for the "BSB" version of the chip, which has 16 pins. The 20-pin datasheet has more pins with additional options. (check wenku.baidu.com/view/ff775115a216147917112855.html )
Just another data point... received some of the 4-way TTP-224 type boards that seem to be working fine. No problem with lock-ups or activating only one key at a time.
I had some PCBs made that I designed for a domestic light switch replacement arduino project. I can toggle and dim from 5 touch pads on the PCB. Also put some 0603 smd LEDs soldered mounted on their sides shining on the pads, works a treat :)
Another thing after some thinking about the C-coupling and those traces you mentioned--these things may be made for mounting in a much more shielded environment than floating about -naked- in 'capacitive' air and hands! I NEED TO FIND YOUR UPDATE VIDEO(S)!
I'm looking for a capacitive touch switch that toggles between either 3 or 4 states with just one button. Any idea if this component exists or how to search it?
I find it somewhat suspicious the chip came with the pin hole soldered shut.. and once you do get pins linked, the functions do not work correctly. It's almost like the company knew the functions do not work correctly and just cover up the holes with solder as to discourage people from finding this out. Come on Tom Tech you should know better! Any thoughts?
I wonder, did you ever get the second shipment with the 16 way? I ordered one myself recently after finding them dirt cheap on ebay. The 16 way only has 5 leds, and 8 output pins. I hooked it up through my arduino and the output from the keys are very strange viewing them through the serial monitor.
Maybe it needs a 3D printed spacer grid thing between all the buttons, so you get a bit of a raised edge and to isolate the buttons from each other. Ordered the one with 16 buttons just now. I'd like to control the Ikea Trafdi smart lights with it and a Pi Zero W. Should be fun. :)
Hello - the 4 Way switch works good when you use batterpower , when i shut off the Powersupply - it begans to work correctly with the rest of the Condensatorpower of the powersupply !!!!
Thanks for sharing! Got one of the 4 touch version. Works perfectly. Is it possible to set the chip to one led on and toggle between other buttons? Got singlemode (sm) on and toggle (tog) but doesn't seem to do what I want. Any suggestions?
I look forward to seeing more touch sensors in later videos :) As you said... it's hard to not want to get your hands on some of the other variations to work out what the heck is going on! Like some other people have mentioned, I would look at mounting it on something to remove the 'hand capacitance / bridging" possibility from the equation, and would be very critical of the circuit implementation - our chinese friends have no regard for chip tolerances at times and make some wonderful 'release the magic smoke' circuits! I'd also love to know how much space you can put between the pads and your fingers... can you put a 1 / 2 mm piece of plastic between your finger and the pad? Glad wrap should work (it does for computer touch pads), so what else can you put the panel behind... And had you thought of playing with computer touch pads... you can get them complete with decoder chip, which can be interfaced with an arduino... You can then define your own 'touch zones' etc...
I find that desoldering wick will suck it right out of those holes--another alternative--wet the solder and thump/slap the PCB to knock out the solder with inertia--may need tor heat after this to smooth.. Filled-in holes: Probably due to a solder-wave swipe?? I agree with the "BAD" verdict.
I guess you did not test the SBMS as of now. You will probably love the response and sensitivity of the 6 touch keys. I use the STM32F072 microcntroller for the capacitive keys and the software is quite complex and takes some resources but after you adjust all those complex parameters it works really well. Anyway I added a key lock like on mobile phones so that there will not be unintentional touches. To unlock just push OK UP and Down in order but it will indicate that on the screen if you touch any key when is locked.
***** Not yet, but after I fit the 8 LiFePo4 cells into the bike, I'll be looking at balance charging and the 2 BMS boards that I have. Then I'll start looking at the SBMS. I did think of you when I was having all that trouble with the capacitive switches!
How did you enable that Toggle Mode? I have this board, and I want the 224 switch to keep the light ON when a pad is touched (momentarily), and then only turn off when another switch is touched.
Didn't have any problems with my four way version. Normal sensitivity and none of the bugs you had. Though mine had a slightly different pcb (at least the silkscreen font). Try putting a piece of plastic or glass on top to lower the sensitivity. After all, in real world applications you wouldn't use the board as is. I connect mine to some copper pads attach to the back of a glad panel, ad replaced the four caps with a lower value.
Help! How to turn on toggle mode in ttp226 I have done all possible connections, read data sheet many times, but nowhere toggle Is written. Ttp226 has too many options to select, but how to use it in toggle Mode. I don't want to use arduino only to toggle output, which is working.
I don't think you can really blame the chip, or even the PCB layout on the bigger unit. Sensitivity defaulted to max, but easily rectified. in 'single' mode, it obviously did what I would have implemented in software, anyway. "Use first detected, ignore all others until none detected'. Think the real fault is the current drawn by the LED's. ?increase the SMD series resistors considerably, maybe? Oh, wait, Julian...you wimped out of building that surface mount 'roulette' thingy' ;-) SMD's aint so bad. I've got to use them at work, even 28-pin 0.5mm spacing chips can still be easily done by an old codger of 58 like me...just buy an SMD practice board from alice, banggood or similar first...
Did you ever get hold of a TTP226? I would love to see your tests on that. I've just ordered a few from China and would be happy to post you one when they arrive in a thousand years (I'm in UK too). Also, I'm intrigued by the brief mention in this video about matrix mode, I'd love to see your investigations into that.
After watching part a and b, There is definitely a rather high percentage of poor quality devices coming out of this Seller... I would not buy from their store. on the positive, love seeing all your post bag videos! How much would you spend on average for these videos in a month?
Next time try adding some fresh lead based solder to mix with the lead free solder which lowers the melting point and you can just heat from the bottom side and suck it from the top side. I hope that makes sense.
Try the unit fixed down to something rather than hand held - it's possible something is coupling to another part of the circuit via your hand. Also it could be a supply noise or instability issue at that particular current, try 100uF across the Vcc and Gnd, or a different supply. The touch pad won't work on my Toshiba laptop when powered by a certain in-car dc-dc converter! How useless is that?
Wow these appear to be very fun for the price! :D But if anyone wants a more reliable capacitive touch sensor, try out the atmel's Q-touch line of chips, and especially the qt1070 witch uses i2c and can (extremely easily) talk to an arduino and output a 8-bit value on how much capacitance is detected. A really nice chip :)
"And the lines (lines from touch pad to IC pin) do not parallel and cross with other lines" Page 4 of the datasheet. So piss poor circuit design is most likely the problem here. Having the lines so close together probably screws up the auto calibration it has built in. Reducing the sensitivity could fix some of the issues.
Strange i am typing this one a keyboard from the 1980s that uses the same technology :P An IBM model F. :). I would say form experience working with capacitative seance PCB is grounding. you need very good grounding. Different pads will also have differing levels of capacitance even flexing the board could cause problems. i would say bad pcb design. The IBM uses 2 pads one 5v the other tied to ground , when you press a key a conductive pad moves towards the pcb causing a change in capacitance how are they doing it with just one pad ? The modern replacement controller i use can be adjusted by increasing or decreasing the mV level that it counts as a key-press. set it too low and you will get pads next to each other activating. Not my work but you may find this interesting. deskthority.net/workshop-f7/beamspring-usb-controller-t6044.html
"Buggy chips, poor layout, that can only mean one thing - I'm going to have to buy more of these"
when i desolder filled holes I find it easier to heat it the pad from one side and have the solder sucker at the opposite end of the hole. of course you will need a vice to hold the board in place. thanks for the video...very helpful
+bd594 Yeah, it's much easier that way, you get a nearly air tight seal when the soldering iron tip is not getting in the way.
+bd594 Yep, always been doing it this way. Piece of cake.
If you can't (because the "other side" is not accessible), solder wick is an easy enough solution.
".. where triggering an adjacent key was a major problem." Well, that's it for touch sensitive controls in nuclear power plants then
That's really weird you should mention nuclear power plants - I was thinking of the Simpsons episode when Homer tries to use the phone and gets a message saying "the fingers with which you have dialled are too fat, if you require operator assistance, mash the keypad with your fist now"
Edit- Just to clarify - I'm not referring to Julian here or being cruel - I wouldn't be able to press these on their own either. It's just what I think of when buttons are too small for adult fingers.
Julian Ilett In order to avoid blocking the text on the PCB, you could have soldered in the headers on the component side, then remove the plastic bases.
Maybe its meant for use behind glass/plastic. Touching the pads directly might not be ideal.
_"... so I'm going to have to buy the 16 way and the one way, but anyway..."_ lovely pun at the end.
Small tip for clearing holes: mount PCB vertically, heat a hole with a soldering iron from one side and use a solder sucker on opposite side :)
you are supposed to use the back for touch. That way the connections are pointing the right way when mounting in a box.
and the numbers kind of indicate that!
Back in 1975 - a 4000 series logic chip with a 10 Meg resistor between input and ground - produced a reliable touch sensitive switch. Picking up mains hum when touched.
I think the toggle behavior we see at the end is when someone would be inputting a 4 digit pin. push to lock in and move onto the next char, when all 4 are entered deselect all to get ready for next input combination. Could be worthwhile looking at the serial output/I2C and analyze how it sends the input as entered.
thanks for your time to show us how it works
Have got the TTP224 board here. Just had a look and the numbers are filed off the chip !!!
Wanted to see if any other details were there, such as manuf date for a 'bad batch' thought.
I know, it's quite late and I don't know if already said it... Through hole pads are easier to clean if you put the "sucker" on one side of the pcb and the soldering iron on the opposite side. And a little dip of flux (or fresh flux containing solder) can help a lot as well. Hope this is helpful anyways. Greetings from Germany!
Julian Ilett With those filled in-holes, I'd either use the heat gun, heat it up and just push the headers in without bothering to suck out the solder, or I'd blob a load of solder all over it, heat it with the soldering iron and just poke the pins through one by one with the solder molten, then just suck or wick away the excess solder. In other words, don't bother trying to get the solder out of the holes, just worry about getting the pins in :)
Also, I'm wondering if those touch pads are actually intended to be extended in some really botchy way, ie by capacitively coupling a wire on to them without making an electrical connection. I'm wondering what happens if you just physically stick a wire to each pad with glue or tape and then touch the end of it? Or perhaps a small square of conductive foil glued to each pad with a wire attached?
Looks like having too many LEDs lit up is causing the chip to shut down. I wonder if the output pins on the chip are driven off the internal voltage regualtor - I imagine that can only handle a few mA. Cheers!!
Yes, an output pin can only source 4mA according to the datasheet. But it does not mention what the limit for all of them is and if it's driven off the regulator.
Julian Ilett measure the voltage at the output pins, preferably with an oscilloscope, and check for "dips". The internal regulator has 2.3V so if you see that, you know the LEDs are driven from it. Btw. you have to specifically search for the "BSB" version of the chip, which has 16 pins. The 20-pin datasheet has more pins with additional options. (check wenku.baidu.com/view/ff775115a216147917112855.html )
if that were the case then why doesn't the chip lock up in momentary normal off mode?
Just another data point... received some of the 4-way TTP-224 type boards that seem to be working fine. No problem with lock-ups or activating only one key at a time.
I had some PCBs made that I designed for a domestic light switch replacement arduino project. I can toggle and dim from 5 touch pads on the PCB. Also put some 0603 smd LEDs soldered mounted on their sides shining on the pads, works a treat :)
Another thing after some thinking about the C-coupling and those traces you mentioned--these things may be made for mounting in a much more shielded environment than floating about -naked- in 'capacitive' air and hands! I NEED TO FIND YOUR UPDATE VIDEO(S)!
The headers were probably wave soldered, so the holes were filled up... :D
I'm looking for a capacitive touch switch that toggles between either 3 or 4 states with just one button. Any idea if this component exists or how to search it?
I find it somewhat suspicious the chip came with the pin hole soldered shut.. and once you do get pins linked, the functions do not work correctly. It's almost like the company knew the functions do not work correctly and just cover up the holes with solder as to discourage people from finding this out. Come on Tom Tech you should know better! Any thoughts?
Love these postbags! Please do more!
I wonder, did you ever get the second shipment with the 16 way? I ordered one myself recently after finding them dirt cheap on ebay. The 16 way only has 5 leds, and 8 output pins. I hooked it up through my arduino and the output from the keys are very strange viewing them through the serial monitor.
Maybe it needs a 3D printed spacer grid thing between all the buttons, so you get a bit of a raised edge and to isolate the buttons from each other. Ordered the one with 16 buttons just now. I'd like to control the Ikea Trafdi smart lights with it and a Pi Zero W. Should be fun. :)
Hi @Julian Ilett, Can i using this IC for my applycation "Water Level"?Thank you.
Hello - the 4 Way switch works good when you use batterpower , when i shut off the Powersupply - it begans to work correctly with the rest of the Condensatorpower of the powersupply !!!!
Thanks for sharing! Got one of the 4 touch version. Works perfectly. Is it possible to set the chip to one led on and toggle between other buttons? Got singlemode (sm) on and toggle (tog) but doesn't seem to do what I want. Any suggestions?
I look forward to seeing more touch sensors in later videos :) As you said... it's hard to not want to get your hands on some of the other variations to work out what the heck is going on! Like some other people have mentioned, I would look at mounting it on something to remove the 'hand capacitance / bridging" possibility from the equation, and would be very critical of the circuit implementation - our chinese friends have no regard for chip tolerances at times and make some wonderful 'release the magic smoke' circuits!
I'd also love to know how much space you can put between the pads and your fingers... can you put a 1 / 2 mm piece of plastic between your finger and the pad? Glad wrap should work (it does for computer touch pads), so what else can you put the panel behind... And had you thought of playing with computer touch pads... you can get them complete with decoder chip, which can be interfaced with an arduino... You can then define your own 'touch zones' etc...
Hi Julian, have you seen the TTP229: 16 Channel Digital Capacitive Switch (I2C) already? They seem to work great!
I find that desoldering wick will suck it right out of those holes--another alternative--wet the solder and thump/slap the PCB to knock out the solder with inertia--may need tor heat after this to smooth.. Filled-in holes: Probably due to a solder-wave swipe?? I agree with the "BAD" verdict.
Thank you for the "Single Touch switch" heads up. Nice!! But my keypads work very well and don't have the holes soldered.
Does a postbag #34 exist?
Since there is a #32a & #32b, postbag #33 is the 34th postbag. Did one get skipped to get it back in sync?
I guess you did not test the SBMS as of now. You will probably love the response and sensitivity of the 6 touch keys. I use the STM32F072 microcntroller for the capacitive keys and the software is quite complex and takes some resources but after you adjust all those complex parameters it works really well.
Anyway I added a key lock like on mobile phones so that there will not be unintentional touches. To unlock just push OK UP and Down in order but it will indicate that on the screen if you touch any key when is locked.
***** Not yet, but after I fit the 8 LiFePo4 cells into the bike, I'll be looking at balance charging and the 2 BMS boards that I have. Then I'll start looking at the SBMS. I did think of you when I was having all that trouble with the capacitive switches!
How did you enable that Toggle Mode? I have this board, and I want the 224 switch to keep the light ON when a pad is touched (momentarily), and then only turn off when another switch is touched.
Didn't have any problems with my four way version. Normal sensitivity and none of the bugs you had. Though mine had a slightly different pcb (at least the silkscreen font).
Try putting a piece of plastic or glass on top to lower the sensitivity. After all, in real world applications you wouldn't use the board as is. I connect mine to some copper pads attach to the back of a glad panel, ad replaced the four caps with a lower value.
Help!
How to turn on toggle mode in ttp226
I have done all possible connections, read data sheet many times, but nowhere toggle Is written.
Ttp226 has too many options to select, but how to use it in toggle Mode. I don't want to use arduino only to toggle output, which is working.
"They are just SO bad, they are intriguing!"
I don't think you can really blame the chip, or even the PCB layout on the bigger unit. Sensitivity defaulted to max, but easily rectified. in 'single' mode, it obviously did what I would have implemented in software, anyway. "Use first detected, ignore all others until none detected'. Think the real fault is the current drawn by the LED's. ?increase the SMD series resistors considerably, maybe?
Oh, wait, Julian...you wimped out of building that surface mount 'roulette' thingy' ;-)
SMD's aint so bad. I've got to use them at work, even 28-pin 0.5mm spacing chips can still be easily done by an old codger of 58 like me...just buy an SMD practice board from alice, banggood or similar first...
With the four button touch pad I found that if you connect TOG and then connect SM the board works fine and does not lock up
Did you ever get hold of a TTP226? I would love to see your tests on that. I've just ordered a few from China and would be happy to post you one when they arrive in a thousand years (I'm in UK too). Also, I'm intrigued by the brief mention in this video about matrix mode, I'd love to see your investigations into that.
No, I gave up on the TTP chips - I prefer the MPR121
thermal touch switch using op_amp
Please tell me that how to do jumper setting for on and off switch in
ttp226 ? like one touch light on and again touch light off
After watching part a and b, There is definitely a rather high percentage of poor quality devices coming out of this Seller... I would not buy from their store.
on the positive, love seeing all your post bag videos!
How much would you spend on average for these videos in a month?
Pardon my ignorance...can these be configured to mimic a switch opening and closing?
Next time try adding some fresh lead based solder to mix with the lead free solder which lowers the melting point and you can just heat from the bottom side and suck it from the top side. I hope that makes sense.
The TTP226 is really frustrating, it has some intense problems too.
Greetings,
Has anyone discovered the cause of this erratic operation?
Is there any way to fix this?
funny. on my cap sens module (4 ), which ic text was sanded of, the toggle mode worked fine ^^ Maybe ded chip?
Try the unit fixed down to something rather than hand held - it's possible something is coupling to another part of the circuit via your hand.
Also it could be a supply noise or instability issue at that particular current, try 100uF across the Vcc and Gnd, or a different supply.
The touch pad won't work on my Toshiba laptop when powered by a certain in-car dc-dc converter! How useless is that?
So, easy way to get solder out of plated through holes. Soldering iron on one side of the board, suck from the other side.
Wow these appear to be very fun for the price! :D
But if anyone wants a more reliable capacitive touch sensor, try out the atmel's Q-touch line of chips, and especially the qt1070 witch uses i2c and can (extremely easily) talk to an arduino and output a 8-bit value on how much capacitance is detected. A really nice chip :)
I guess you could fix these by pasting a cardboard or paper with small holes in the positions of the switches?
To be fair, i think the touch sensitiveness has to do with you touching the bare board, which would be silly in practice.
where do you buy the chip, not the whole board??
No need to suck out the solder, use a tooth pic and soldering iron .... you will get a leaner hole too.
"And the lines (lines from touch pad to IC pin) do not parallel and cross with other lines" Page 4 of the datasheet. So piss poor circuit design is most likely the problem here. Having the lines so close together probably screws up the auto calibration it has built in. Reducing the sensitivity could fix some of the issues.
Power supply noise maybe?
@simon There are already two bypass caps on the board.
Use solder wick instead of horrible sucker.
Strange i am typing this one a keyboard from the 1980s that uses the same technology :P An IBM model F. :). I would say form experience working with capacitative seance PCB is grounding. you need very good grounding. Different pads will also have differing levels of capacitance even flexing the board could cause problems.
i would say bad pcb design. The IBM uses 2 pads one 5v the other tied to ground , when you press a key a conductive pad moves towards the pcb causing a change in capacitance how are they doing it with just one pad ?
The modern replacement controller i use can be adjusted by increasing or decreasing the mV level that it counts as a key-press. set it too low and you will get pads next to each other activating.
Not my work but you may find this interesting.
deskthority.net/workshop-f7/beamspring-usb-controller-t6044.html
Made for thin chineese fingers :D
You have large western digits, not china digits
These chips seem to be really untrustworthy. Wouldn't use them in something serious. There has to be something better.