Wall warts. Plug mounted power supplies that turn mains voltage into low voltage DC on a barrel jack to power a piece of equipment. We’ve all got a load of them for our various devices, most of us to the extent that it becomes annoying. [Mikeselectricstuff] has the solution, in the shape of a USB-C PD power supply designed to replace a barrel jack socket on a PCB.
The video below provides a comprehensive introduction to the topic before diving into the design. The chip in question is the CH224K, and he goes into detail on ordering the boards for yourself. As the design files are freely available, we wouldn’t be surprised if they start turning up from the usual suppliers before too long.
We like this project and we can see that it would be useful, after all it’s easy to end up in wall wart hell. We’ve remarked before that USB-C PD is a new technology done right, and this is the perfect demonstration of its potential.
Megan in M3GAN 2.0 gets one of those boards implanted as a non-lethal inhibitor chip :)
With a bit of structural anything to support this board and cover the shorting to nearby connector shields potential I could see this being worthwhile if you really really buy into the USB-C ecosystem I guess. I think I’d go for 3d printing a mould/former to fill with potting compound – I suspect easier to print a permanent shell to fill up than the separable and reusable multipart mould.
But I’d still rather avoid USB-C as much as possible for as long as possible – the standard is a mess, so even before you get to all the not compliant stuff out there silent failures are just too common, and with all the not compliant stuff especially quite possibly destructive silent failures… So I’d far rather have the barrel jack and the engraved +/- centre pin and voltage marking so to screw up takes a human error, not a perfectly understandable expectation that plugging this in it will just work – I want the mistake to actually be mine not maker of the device/cable etc I just trusted erroneously.
Plus if you do ever lose or damage the right supply with barrel jacks replacements and repairs are cheap and easy, its also dependable and mechanically much tougher (in general anyway) connector. Helps having huge footprint for only 2 contacts.
Oh also the print to fill option also allows you to print the voltage this particular board is set up for as a pattern into the outer case each time you assemble one – so should you ever de solder the connector for reuse you don’t have to test it that one says 9V on the top. Which sounds like a far better idea than a fancier reuseable mould without that marking, as you’d need to be making a huge number of them in a particular voltage to be worth addign that complexity to the mould.
I have to agree with everything you said. If I wanted to hamonise everything, I’d be quicker to move everything to a 12VDC barrel jack with maybe a buck regulator onboard for 9 and 5VDC output, then I would mess around with USB-C PD.
I actually have some dirt cheap buck boards that cost a few cents each and can handle up to 1A output when you add a small heatsink.
“barrel jack and the engraved +/- centre pin and voltage marking so to screw up takes a human error”
It doesn’t take a human error, it takes a crap wall-wart. Which is the exact same problem with plugging in a USB-C supply if you don’t know how it works.
One of the big issues with power supplies in general is that “9V, center pin positive” isn’t actually enough of a spec for a power supply. No load overshoot, load regulation, ripple, etc. all need to be considered as well.
While this solution addresses the problems of barrel connector (variety of voltages, pin diameter, barrel diameter), it create a new one:
Barrel connectors are rock-solid. They are to break. They are firmly anchored on the board. This is not the case with USB-C and those filmsy piece of solid wire. That will bend and break.
The solution would be a case + pins that have a form-factor similar to a barrel connector, with a USB-C instead of a round hole, and a bit of PCB exposed with solder bridges to select the voltage.
I am wondering if I am just lucky or something, but I have had 0 problems with using USB as a power source. I do tend to only buy power bricks that will do PD of at least 12V though, and I don’t go super cheap. As for cables, I look at the reviews and try to stick with a known brand name that is likely to want to preserve their reputation. Biggest gripe I have had is around manufactures making dumb choices involving the capability of the port (looking at you HP…)
Or Dell cheating in a higher-power USB-C spec. I mean, if they made a little “USB-C PD to fake-o Dell 130W” adapter (which they could do!) it’d be fine, but seriously.
i have a little pile of micro usb breakout boards that have already become my default for 5V projects. with another cheap board, i can charge a lipo cell off of it too. you only have problems if you use the new features…for 5V everything is easy :)
Problem with USB-C PD is, it always has a 5V fallback. If you have a device that needs 12Volts, you can request it from the power supply, but the power supply is allowed to deliver just 5Volts.
You can NOT retrofit any random device by replacing the barrel jack, most old devices will die if they get the wr9ng voltage.