Every one of your videos goes away beyond my understanding since I'm not into electronics. However, I really enjoy watching your videos and I look forward to your new series!
USB ports do not limit the current to 100mA before negotiation. There is no requirement in the standard for them to do this, and it is almost unheard of for them to limit the current 100mA before negotiation. It is just a "play nice" software request thing.
As an electronics engineering student, this is amazing. Off the top of my head: - Won't the 7seg-displays use up a lot of power? About 40mW * 6 = 240mW ~ 10% of your available power, or am I overestimating? Substitute for lcd? - You could also use an attiny to make the supply effectively a usb keyboard, that outputs all the values as typed text (in notepad or something), you can even have two-way communication using caps/num/scrollock. Maybe for a future usb-stick size nanoSupply :) ?
IIRC the dual muxed display at a reasonable brightness took about 40mA or so (200mW). It's a lot, but I was fixated on having LED displays at the time. I have a trick up my sleeve, those displays are not the final solution.
I actually got a recent design that combined the USB and batteries into one unit - USB charges the batteries, and batteries powers a boost converter capable of at most 36V at 2A. I called that MTD295A (5 cells, there was 3 designs differ in only the amount of Li-Ion cells used: 295A with 5 cells, 299A with 9 cells and 292B with 12 cells).
USB ports on a computer are generally all centrally fused (usb_org/developers/whitepapers/power_delivery_motherboards_pdf), so are capable of supplying much more than 500ma/1000ma that most people quote; Current limiting on the USB ports in a per port basis is generally only on hubs, it is not designed as a "current cop" to stop you going over the allowable current, only to protect you and your devices. Idea related to above; Put some form of adjustable current limiting on the sour
I like the idea. I would like a boost convertor in it so you could get roughly 0-12VDC output voltage. You could get fancy with computer controlled set points, but I think a two knob interface is a great starting point.
I would buy one as soon as the kit comes available. This thing is way more useful to me than the µCurrent. Seems really awesome for school work and quick little projects at home that don't need serious power. Can't wait for the follow up video! :)
Thank you Dave!!!! I was really looking forward to getting info about USB interfacing from you. Few suggestions: 1. Please give some detail about USB interfacing options and what is the best one according to you. Love to hear your views about FT232 etc (FTDI chips) 2. It would be a nice idea to have the computer read the voltage and current being supplied by the PSU. A small application in Visual Basic (or some thing) that can give live readings on computer as well as log the history tc :-)
Also, there are USB Power Delivery (USB PD) which allow a USB port to supply much more than 2.5 Watts. Though probably no one implements this at the current time and afair it is still a draft, it might be good to look at the coverage of this and take a future implementation of this into consideration. (You are of course right that 2.5 Watts is really neat, but if you really think about it - very often this is not enough.)
Don't forget that newer 'iPad compatible' motherboards and computers can output 10w via USB. This is the case for all the ports on all of the 2011 MacBooks if I recall correctly. BTW, I love the thing, and I would totally buy it!
Futher ideas (may be interesting): 1) Lead-acid battery powered regulated supply. Perfect isolation and overcome 2.5W power limit on USB 2) Redesign a cheap "electronic tramsformer" for halogen lamps into normal unregulated power supply. Power levels of 50-300W can be obtained easily at below $10.
Don't limit it to 2.5W as there are USB chargers that can do up to 10W and a dual USB cable (like those for some DVD drives) can do 5W. Neat idea and very handy.
PL2303 (cheaper than FT323) to add a "com" port in order to control/log it via software. It should be trivial since there is an (PIC ?) mcu (judging from the use of rotary encoders). High current output selection switch (1000 mAmps) for USB3 ports or Dual USB2 connection.
Nice! Would be really cool if u did a function generator as well. The power limits from the USB would not be as big a problem, and it would be super neat to have an easy to bring generator...
Supporting USB 3.0 power and/or USB charging protocol would be good, for USB ports that support it, so if more power is available, it can be able to draw more power from the port.
Pretty simple idea. I feel it needs either a low power LCD or a way to turn off the LED display so you can save a few precious ma for the project, but honestly if you're going to be going that close "to the rails" this may not be the best option.
I've come up with a few solutions like this myself (albeit mostly fixed voltage), I have a couple of bench supplies but sometimes you need more voltages, and PC PSUs are great for tons of relatively stable power. E.g. I've modded a USB port so it's wired directly to the 5v PSU rail rather than running through the motherboard, so current is less limited, but no data. I've also made a box with banana sockets on, wired to 12v/5v/3.3v/GND, connected back to a SATA power connector inside the PC.
If it's specifically for a PC USB port (not any generic USB power adaptor etc) then I would want it as small as possible and have all the control and monitoring on the PC. You could then have data logging and automated control, pre-sets etc and no bulky display/input on the device.
Depending on how you do a sense/ref voltage, it would be nice to have an extra lead that would be a voltmeter. So with analog switch depending on microcontroller, you could sample the supply output, then switch in the extra input and read it, Or use a ADC on the microcontroller. It would be nice to be able to measure some other voltage when you power up something your are testing and a button then for the voltmeter readout/mode. (Might also use this extra probe as ultra low volt/current sense
I'd say make it a 'hybrid' power supply! Be able to control from USB, but also powered from USB up to 2.5W. If standard power pack is connected it will switch to that power source by itself. I guess the power output would be limited to 2.5-10W depending on the design, so like 0-1A output at 0-12V or something. The only issue with that is that you'd need a buck-boost converter for that..
Personally, I would love to see this project come through. I am an EE student, and I play around with things on the go, sometimes labs have another class and we can't go in so I either end up dropping the curiosity, or I wait until I can use the lab. Either way, most of the things I like to play with is low power, mostly digital ICs, and this sounds like a nifty project I could come in hand with! 100mA would be bare minimum, and as another commenter said, maybe USB Y-Cable is able to up the game
Pt2: Yeah and I also have an LM317-based linear regulator designed with 12v input in mind. It's not terribly efficient, but does the job when you need additional voltage, and it's not common you need a lot of power outside of the 12/5/3.3v rails anyway.
This is a great idea Dave... I wouldn't mind it being bigger, As long as you make it as flat as possible, (about the thickness of a kindle maybe a bit thicker) So it can easily fit in to a laptop bag/pouch without causing any damage to the other stuff that's already in the bag/pouch (so, no sharp edges, parts, or protrusions ).....
vape-pun-to-come More realistically, better power components can be used if it's the size and shape of the laptop charging brick. B port on one end, 3 or 4 output binding posts on the other, reusable generic USB cable, computer controlled and monitored buck/boost isolated DC/DC converter inside.
Here's an idea for one version: since it's USB, remove the controls and display, add a simple GUI (and/or open API) that replaces them. You have your laptop anyway. You could make it very tiny, then. Oh, I see similar comments below - so count this as another vote for that.
Some of mine ideas: 1. powering from 1 to 3 usb ports to get 1.5A, it would be useful. 2. programmable trigger for start/stop loging and start/stop output. 3. Data loging to internal memory when connected to, for example usb charger, car audio, etc. 4. Voltage and Amps meter witch loging capabilities.
Yes, this would be more versatile! also, @ the current side, I know your target is for a laptop USB socket, BUT these days we all have USB socket output chargers laying around which range from 500mA to 2AMPS (for the iPad type quick chargers)!! Can we make it work with the full capability if we do have a mains usb charger as well?? This would be AWESOME!!
I use a bus pirate as a sort of USB power supply (I find it pretty useless anything else) .. It's useful as a PSU because I can turn it on and off via its shell interface which is really handy when working with micros etc as you can power cycle without your hands leaving the keyboard. So my feature request would be to have some sort of control interface over USB (with the hardware knobs too if possible). Having a DC-DC booster for more than 5v would be nice too.
Beware that engineers (well MBA's, actually) cut corners to increase profit. There may be a lot of computers in the wild that cannot source much current and do not adhere to any specs. Second, if you are using USB, might as well exchange data with a client on the PC to show current draw and voltage. You can make it programmable and save the BOM on the LEDs and drivers. Trivial to program and you can have a window with those same readings and maybe even TREND data for under-voltage.
Instead of fastening the board to the top of a box, why not make it slightly smaller than the inside of the box so that you can sticky-tape the board to the bottom of the inside of the box (assuming pots are mounted on the top of the board) like this: tinyurlDOTcom/uUSBinBox. That way,the sides of the box protect the unit. Another way would be to screw the board to the box, but upside down, so the guts are inside the box. Cut holes in the bottom to clear displays, knobs, jacks, etc.
@ battery power supply, I know it's late for this project . . . , but if it is at all possible: How about including, say, 2 (or more) programmable buttons!! I would LOVE a couple programmable preset voltage/current buttons (or more if they will fit) It would work with your included uController, just press & hold to set, & quick press to sellect!! (or perhaps one being voltage button, the other current . . . ) [momentary buttons = small/ Cheap!] Would be nice for this supply TOO :)
Nah, I like knobs. Quick and easy access to the power supply settings. I don't want to be clicking around in a UI just to change the max current or something like that.
More practical and relevant than the battery powered one actually. I think. Especially the fact that it is isolated. Digital control via USB would be fun. :) And if it would identify it's power usage to the USB host like the specs require. You can draw 500mA on USB, but according to spec only if the Host allows it. Not worth the cost perhaps, considering that the world is already full of 'farting USB novelty toys' that don't do it right. :)
10A at 30V is a lot of power, im already habing problems getting my 0-40V 100W sepic to work as intended without overheating. for 10A you need some wide tracks, and for 30A you would have to use a solid cooper wire of about 4 or 5 mm as tracks. further more 30A is a lot, i use a circuit breaker anytime i work with lead batteries because of that and even with the 15A CB it can still evaporate 2mm track in the time it takes it to disconnect. u would need a really quick regulation circuit there.
Hi Dave! You might consider designing the new gadget in a way that it can handle the extra power that comes from a dual USB connector cable (Dual USB A to Micro B - USB cable). Like the one that comes with portable harddrives without wall warts. That would be 5 W rather than 2.5 W. nixxon
also, if you have a mcu on board, you might add a simple CDC interface so that it can send data to PC on current and voltage (or even receive data from pc for set current and voltage, but I think readout is more then enough)
He could just open-source the design and leave a couple of pins free on the pic and let users add the function gen software themselves. Also the pic could auto negotiate the USB 3 requirements.
It would be nice to have a slick design of it. Why not use a LCD screen something similar to calculator or ur digital watch. Also the control nobs need not to be that big even for a person with a big hand. Also, it would be nice to have a port with a fixed 5V supply for the project where you need multi supply voltage.
Hi Dave, You could incorporate a data logger into it. It will require to make a PC program and I don't know if you're willing to do so, but I think this could be a neat feature. BR
Are you going to isolate and deal with data lines at all? IIRC you only are allowed to suck a very tiny amount of power from (some controllers might not care) USB portss unless you talk to the machine and request more.
Pc/laptop usb can only supply 100mA until the device has negotiated with the host that it needs more (some computers can now supply 1A or more over usb). A simple mcu with hardware usb support would overcome this problem though
Hi, I'm a huge fan and I absolutely love your teardown tuesdays, (request: spellman/Glassman high voltage supplys.) I'm a mere lowly undergrad but am headed into EE for RF and Power Engineering because I love my Black-Magic. Anywho, have you considered incorporating a little Boost Converter into your next USB-PSU? Then you could potentially leverage that 2-watts for 12, 13.8, 15 etc variable voltages! That'd be cool to see.
I like the idea, but haw about a plain LCD display and a switchable backlight to save some power. Also it should be able to limit the power to what ever the computer says, i.e. in some cases you might just be allowed to use lika 100mA or so.
Can it be adjusted above 5v? Maybe a pin and sleeve connector that comes out at a right angle from the board to keep it slim. Do you plan on leaving the connections to the load just solder able?
Neat idea - I like it! Problem may be the specification (at least previously) was 100mA until protocol negotiation was completed and the device asked for 500mA. Is this not true any more? I am aware that "most" USB host adapters just tie the 5v output to a rail, but some may not. Of course, you could just do vUSB on your micro or something similar (and have probably already thought of this!)
I would assume with such a project you would want it to use as little power as possible and be as efficient as possible. Wouldn't it save power to use one small LCD screen with 3-4 digits or maybe one 1x8 lcd? Also, there's the usb charger standard which allows them to demand up to 1.5 A. How about adding a switch allowing users to limit to 0.5 or go higher? Sending v/a out through USB would be great...would be nice if you at least talk about (isolation etc) even if you don't to do it...
He's limiting to 2.5W or 5V @ 500mA. Would be cool if this would detect standard downstream port vs charging downstream port. This way if the "USB Port" can supply 1.5A, the uSupply would be able to use it.
How about making it so if you wish u can add a 2nd usb cable for more current and/or notebooks that dont give the full spec. What about making it a hub also? (Then I dont have to carry a separate hub) What about an external power input for an SLA or plugpack? I have had applications where I need 3.3v with at least 2amps, and I was forced to go and use the desktop (and steal the 3.3v from the internal switchmode, quick and dirty but it did the job surprisingly well)
Great idea! Does it have protection against drawing too much power from a USB port? I've seen a few PCs which do not have a PTC thermistor or any sort of current protection on their USB ports (!!!) now. Usually you find out about it when a USB device or cable shorts, and the PC's mainboard catches fire. Maybe make it adjustable using a jumper to make it possible to utilize a 2A USB power supply (like the iPad power brick, for instance)? That, and reverse current protection, and I'd buy one!
Are you going to limit the voltage to the USB 5V or do you plan on having a boost converter? Neat project. I would like to hear more on how to do the isolation.
Not only is this something I would buy I am very excited to see it develop! Brilliant!
Every one of your videos goes away beyond my understanding since I'm not into electronics. However, I really enjoy watching your videos and I look forward to your new series!
As available power is limited, I think LCD would be a better choice for display.
USB ports do not limit the current to 100mA before negotiation. There is no requirement in the standard for them to do this, and it is almost unheard of for them to limit the current 100mA before negotiation. It is just a "play nice" software request thing.
I developed these projects after hours when I was working full time.
No, it's not just two extra traces. You have to isolate the data too.
Congratulations Dave with this idea!! I promise my thumbs up :) I always enjoy these build videos with a cup of coffee :)
As an electronics engineering student, this is amazing.
Off the top of my head:
- Won't the 7seg-displays use up a lot of power? About 40mW * 6 = 240mW ~ 10% of your available power, or am I overestimating? Substitute for lcd?
- You could also use an attiny to make the supply effectively a usb keyboard, that outputs all the values as typed text (in notepad or something), you can even have two-way communication using caps/num/scrollock. Maybe for a future usb-stick size nanoSupply :) ?
good idea, i'm gonna have to pick one up when you finish the design.
Great idea, can't wait for more. That's what I want to have for months!
Read the silkscreen on the front of the prototype.
Very nice! Software control of the voltage and current limits would be a useful feature.
IIRC the dual muxed display at a reasonable brightness took about 40mA or so (200mW). It's a lot, but I was fixated on having LED displays at the time. I have a trick up my sleeve, those displays are not the final solution.
Now that's a very neat project! I'm definitely looking forward to seeing more of the series!
Thanks dave ;-)
I actually got a recent design that combined the USB and batteries into one unit - USB charges the batteries, and batteries powers a boost converter capable of at most 36V at 2A. I called that MTD295A (5 cells, there was 3 designs differ in only the amount of Li-Ion cells used: 295A with 5 cells, 299A with 9 cells and 292B with 12 cells).
USB ports on a computer are generally all centrally fused (usb_org/developers/whitepapers/power_delivery_motherboards_pdf), so are capable of supplying much more than 500ma/1000ma that most people quote;
Current limiting on the USB ports in a per port basis is generally only on hubs, it is not designed as a "current cop" to stop you going over the allowable current, only to protect you and your devices.
Idea related to above;
Put some form of adjustable current limiting on the sour
I like the idea. I would like a boost convertor in it so you could get roughly 0-12VDC output voltage. You could get fancy with computer controlled set points, but I think a two knob interface is a great starting point.
the USB lab supply is a really nice idea i was always looking for a cheap power supply and this thing would be great! amazing idea!
I would buy one as soon as the kit comes available. This thing is way more useful to me than the µCurrent. Seems really awesome for school work and quick little projects at home that don't need serious power. Can't wait for the follow up video! :)
Thank you Dave!!!! I was really looking forward to getting info about USB interfacing from you. Few suggestions:
1. Please give some detail about USB interfacing options and what is the best one according to you. Love to hear your views about FT232 etc (FTDI chips)
2. It would be a nice idea to have the computer read the voltage and current being supplied by the PSU. A small application in Visual Basic (or some thing) that can give live readings on computer as well as log the history
tc :-)
Also, there are USB Power Delivery (USB PD) which allow a USB port to supply much more than 2.5 Watts. Though probably no one implements this at the current time and afair it is still a draft, it might be good to look at the coverage of this and take a future implementation of this into consideration. (You are of course right that 2.5 Watts is really neat, but if you really think about it - very often this is not enough.)
Don't forget that newer 'iPad compatible' motherboards and computers can output 10w via USB. This is the case for all the ports on all of the 2011 MacBooks if I recall correctly. BTW, I love the thing, and I would totally buy it!
Futher ideas (may be interesting):
1) Lead-acid battery powered regulated supply. Perfect isolation and overcome 2.5W power limit on USB
2) Redesign a cheap "electronic tramsformer" for halogen lamps into normal unregulated power supply. Power levels of 50-300W can be obtained easily at below $10.
You can go to higher power when you switch USB to "charger" mode. I think it is about 800 or 900mA! :)
Don't limit it to 2.5W as there are USB chargers that can do up to 10W and a dual USB cable (like those for some DVD drives) can do 5W. Neat idea and very handy.
PL2303 (cheaper than FT323) to add a "com" port in order to control/log it via software. It should be trivial since there is an (PIC ?) mcu (judging from the use of rotary encoders).
High current output selection switch (1000 mAmps) for USB3 ports or Dual USB2 connection.
Nice! Would be really cool if u did a function generator as well. The power limits from the USB would not be as big a problem, and it would be super neat to have an easy to bring generator...
Supporting USB 3.0 power and/or USB charging protocol would be good, for USB ports that support it, so if more power is available, it can be able to draw more power from the port.
SB cables, it will make life a bit easier in the long run; also, read that whitepaper, it is a good read.
Pretty simple idea. I feel it needs either a low power LCD or a way to turn off the LED display so you can save a few precious ma for the project, but honestly if you're going to be going that close "to the rails" this may not be the best option.
I've come up with a few solutions like this myself (albeit mostly fixed voltage), I have a couple of bench supplies but sometimes you need more voltages, and PC PSUs are great for tons of relatively stable power. E.g. I've modded a USB port so it's wired directly to the 5v PSU rail rather than running through the motherboard, so current is less limited, but no data. I've also made a box with banana sockets on, wired to 12v/5v/3.3v/GND, connected back to a SATA power connector inside the PC.
If it's specifically for a PC USB port (not any generic USB power adaptor etc) then I would want it as small as possible and have all the control and monitoring on the PC. You could then have data logging and automated control, pre-sets etc and no bulky display/input on the device.
Depending on how you do a sense/ref voltage, it would be nice to have an extra lead that would be a voltmeter. So with analog switch depending on microcontroller, you could sample the supply output, then switch in the extra input and read it, Or use a ADC on the microcontroller. It would be nice to be able to measure some other voltage when you power up something your are testing and a button then for the voltmeter readout/mode. (Might also use this extra probe as ultra low volt/current sense
I'd say make it a 'hybrid' power supply! Be able to control from USB, but also powered from USB up to 2.5W. If standard power pack is connected it will switch to that power source by itself. I guess the power output would be limited to 2.5-10W depending on the design, so like 0-1A output at 0-12V or something. The only issue with that is that you'd need a buck-boost converter for that..
Personally, I would love to see this project come through. I am an EE student, and I play around with things on the go, sometimes labs have another class and we can't go in so I either end up dropping the curiosity, or I wait until I can use the lab. Either way, most of the things I like to play with is low power, mostly digital ICs, and this sounds like a nifty project I could come in hand with! 100mA would be bare minimum, and as another commenter said, maybe USB Y-Cable is able to up the game
Pt2: Yeah and I also have an LM317-based linear regulator designed with 12v input in mind. It's not terribly efficient, but does the job when you need additional voltage, and it's not common you need a lot of power outside of the 12/5/3.3v rails anyway.
This is a great idea Dave...
I wouldn't mind it being bigger, As long as you make it as flat as possible,
(about the thickness of a kindle maybe a bit thicker)
So it can easily fit in to a laptop bag/pouch without causing any damage to the other stuff that's already in the bag/pouch (so, no sharp edges, parts, or protrusions ).....
vape-pun-to-come More realistically, better power components can be used if it's the size and shape of the laptop charging brick. B port on one end, 3 or 4 output binding posts on the other, reusable generic USB cable, computer controlled and monitored buck/boost isolated DC/DC converter inside.
Sounds great! I'm looking forward to it.
Ooooh, I always wanted one like these. Especially together with a USB isolator like ADuM[34]160.
Here's an idea for one version: since it's USB, remove the controls and display, add a simple GUI (and/or open API) that replaces them. You have your laptop anyway. You could make it very tiny, then.
Oh, I see similar comments below - so count this as another vote for that.
Some of mine ideas:
1. powering from 1 to 3 usb ports to get 1.5A, it would be useful.
2. programmable trigger for start/stop loging and start/stop output.
3. Data loging to internal memory when connected to, for example usb charger, car audio, etc.
4. Voltage and Amps meter witch loging capabilities.
Looks great, very practical. I would love to have one.
Oh, and don't forget the 12volt USB out chargers for the car, some of them can put out 1AMP or more!!
Yes, this would be more versatile!
also, @ the current side, I know your target is for a laptop USB socket, BUT these days we all have USB socket output chargers laying around which range from 500mA to 2AMPS (for the iPad type quick chargers)!!
Can we make it work with the full capability if we do have a mains usb charger as well??
This would be AWESOME!!
I use a bus pirate as a sort of USB power supply (I find it pretty useless anything else) .. It's useful as a PSU because I can turn it on and off via its shell interface which is really handy when working with micros etc as you can power cycle without your hands leaving the keyboard. So my feature request would be to have some sort of control interface over USB (with the hardware knobs too if possible). Having a DC-DC booster for more than 5v would be nice too.
its 2/18/2019 and id love one also!!! pretty neat!
PC control and readout over USB is cheaper and requires less space on PCB. Great project! Very interested how you did isolation...
Beware that engineers (well MBA's, actually) cut corners to increase profit. There may be a lot of computers in the wild that cannot source much current and do not adhere to any specs. Second, if you are using USB, might as well exchange data with a client on the PC to show current draw and voltage. You can make it programmable and save the BOM on the LEDs and drivers. Trivial to program and you can have a window with those same readings and maybe even TREND data for under-voltage.
This probably combines very well with an iPhone/iPad 10 Watt charger. So please use components for up to 10 Watts.
Instead of fastening the board to the top of a box, why not make it slightly smaller than the inside of the box so that you can sticky-tape the board to the bottom of the inside of the box (assuming pots are mounted on the top of the board) like this: tinyurlDOTcom/uUSBinBox. That way,the sides of the box protect the unit.
Another way would be to screw the board to the box, but upside down, so the guts are inside the box. Cut holes in the bottom to clear displays, knobs, jacks, etc.
I think it's 2.5 W actually. So that's around 200 mA @ 12V. Could power a lot of things.
@ battery power supply,
I know it's late for this project . . . , but if it is at all possible:
How about including, say, 2 (or more) programmable buttons!!
I would LOVE a couple programmable preset voltage/current buttons (or more if they will fit)
It would work with your included uController, just press & hold to set, & quick press to sellect!!
(or perhaps one being voltage button, the other current . . . )
[momentary buttons = small/ Cheap!]
Would be nice for this supply TOO :)
Look at the silkscreen.
The isolation isn't rocket science, a commercial DC-DC converter module does the trick.
Nah, I like knobs. Quick and easy access to the power supply settings. I don't want to be clicking around in a UI just to change the max current or something like that.
Can't wait!
More practical and relevant than the battery powered one actually. I think.
Especially the fact that it is isolated. Digital control via USB would be fun. :)
And if it would identify it's power usage to the USB host like the specs require.
You can draw 500mA on USB, but according to spec only if the Host allows it.
Not worth the cost perhaps, considering that the world is already full of 'farting USB novelty toys' that don't do it right. :)
Just in what I'm working on!!!!! I can't believe this :(
I'd say a dual USB option to bring it up to around 5 watts would be a good idea.
10A at 30V is a lot of power, im already habing problems getting my 0-40V 100W sepic to work as intended without overheating.
for 10A you need some wide tracks, and for 30A you would have to use a solid cooper wire of about 4 or 5 mm as tracks. further more 30A is a lot, i use a circuit breaker anytime i work with lead batteries because of that and even with the 15A CB it can still evaporate 2mm track in the time it takes it to disconnect.
u would need a really quick regulation circuit there.
Hi Dave!
You might consider designing the new gadget in a way that it can handle the extra power that comes from a dual USB connector cable (Dual USB A to Micro B - USB cable). Like the one that comes with portable harddrives without wall warts. That would be 5 W rather than 2.5 W.
nixxon
As many here suggested can you ramp up the max current in case one would like to use a USB Y-cable with a laptop.
also, if you have a mcu on board, you might add a simple CDC interface so that it can send data to PC on current and voltage (or even receive data from pc for set current and voltage, but I think readout is more then enough)
He could just open-source the design and leave a couple of pins free on the pic and let users add the function gen software themselves. Also the pic could auto negotiate the USB 3 requirements.
Who said it was 5V? Look at what the silkscreen says...
Great idea, I would like to purchase one!
Indeed. I have not looked into that new stuff myself but I think the 500mA barrier dropped, right?
+1 here
USB3.0 can supply up to 7.5W (1.5A @ 5V)
This is an awesome idea!!!
It would be nice to have a slick design of it. Why not use a LCD screen something similar to calculator or ur digital watch. Also the control nobs need not to be that big even for a person with a big hand.
Also, it would be nice to have a port with a fixed 5V supply for the project where you need multi supply voltage.
Hi Dave,
You could incorporate a data logger into it. It will require to make a PC program and I don't know if you're willing to do so, but I think this could be a neat feature.
BR
Are you going to isolate and deal with data lines at all?
IIRC you only are allowed to suck a very tiny amount of power from (some controllers might not care) USB portss unless you talk to the machine and request more.
Pc/laptop usb can only supply 100mA until the device has negotiated with the host that it needs more (some computers can now supply 1A or more over usb). A simple mcu with hardware usb support would overcome this problem though
Awesome! I love it!
Looks interesting. It would be nice if it was programmable and maybe had some kind of data logging capability. Built in uCurrent would also be nice.
Hi, I'm a huge fan and I absolutely love your teardown tuesdays, (request: spellman/Glassman high voltage supplys.) I'm a mere lowly undergrad but am headed into EE for RF and Power Engineering because I love my Black-Magic. Anywho, have you considered incorporating a little Boost Converter into your next USB-PSU? Then you could potentially leverage that 2-watts for 12, 13.8, 15 etc variable voltages! That'd be cool to see.
I like the idea, but haw about a plain LCD display and a switchable backlight to save some power. Also it should be able to limit the power to what ever the computer says, i.e. in some cases you might just be allowed to use lika 100mA or so.
Can it be adjusted above 5v? Maybe a pin and sleeve connector that comes out at a right angle from the board to keep it slim. Do you plan on leaving the connections to the load just solder able?
I would like to get one someday as I have loads of USB ports, but not only one remotely regulated power supply.
I will buy some!
I never had issues using Pl2303. I know there is many PL2303 imitations out there though that the official driver doesn't accept.
Neat idea - I like it! Problem may be the specification (at least previously) was 100mA until protocol negotiation was completed and the device asked for 500mA. Is this not true any more? I am aware that "most" USB host adapters just tie the 5v output to a rail, but some may not. Of course, you could just do vUSB on your micro or something similar (and have probably already thought of this!)
A great thing would be that it could be interfaceable from computer(it has USB connection)
reset on the Arduino is done via modem control lines right? the cheap cp210x modules don't bring those pins out..
I designed and built it myself of course.
Wow, how did I not see that. Will you explain how this works in a later video?
Just like one of those cute pocket dso's you ripped apart.
I would assume with such a project you would want it to use as little power as possible and be as efficient as possible.
Wouldn't it save power to use one small LCD screen with 3-4 digits or maybe one 1x8 lcd?
Also, there's the usb charger standard which allows them to demand up to 1.5 A. How about adding a switch allowing users to limit to 0.5 or go higher?
Sending v/a out through USB would be great...would be nice if you at least talk about (isolation etc) even if you don't to do it...
Nice idea! How about a buck/boost converter to get voltages of up to like 12V?
I suppose you could have the control and display on a GUI if you wanted to make it as small as possible.
I was just going to ask what the quiescent current was with no load attached
Dave don't forget to do PC control through the USB
He's limiting to 2.5W or 5V @ 500mA. Would be cool if this would detect standard downstream port vs charging downstream port. This way if the "USB Port" can supply 1.5A, the uSupply would be able to use it.
Whatabout a cheapo Oscilloscope add-in? You could just use a USB-soundcard AIO chip, basic but could be very helpful and still cheap/simple.
Непривычно как-то, Давид моложе выглядит.
Hi Dave, awesome idea.
Wouldn't it be easier to have a little LCD screen instead of the 7 seg displays ?
How about making it so if you wish u can add a 2nd usb cable for more current and/or notebooks that dont give the full spec. What about making it a hub also? (Then I dont have to carry a separate hub) What about an external power input for an SLA or plugpack? I have had applications where I need 3.3v with at least 2amps, and I was forced to go and use the desktop (and steal the 3.3v from the internal switchmode, quick and dirty but it did the job surprisingly well)
I want one now! Dave any thoughts on stepping up the voltage to 12 volts?
Great idea!
Does it have protection against drawing too much power from a USB port? I've seen a few PCs which do not have a PTC thermistor or any sort of current protection on their USB ports (!!!) now. Usually you find out about it when a USB device or cable shorts, and the PC's mainboard catches fire. Maybe make it adjustable using a jumper to make it possible to utilize a 2A USB power supply (like the iPad power brick, for instance)? That, and reverse current protection, and I'd buy one!
I love it!
Are you going to limit the voltage to the USB 5V or do you plan on having a boost converter?
Neat project. I would like to hear more on how to do the isolation.