A few months ago I anticipated the need to measure current and voltage on a few different USB chargers. I was going to cut up a USB cable, but I decided this might be a good opportunity to design a printed circuit board. Having never designed a PCB before, a simple USB breakout would be a good way to dip my toes into the PCB design waters. For some reason it's taken me months to get around to posting about it. Go figure.
It turns out that designing simple circuit boards isn't all that difficult. There's a surprising amount of free EDA software available and anyone willing to spend some time learning the software can churn something out. I went with the open source EDA suite KiCAD because I had heard good things about it and it’s open source.
I've also read good things about OSH Park and I used the OSH Park PCB service to get the boards manufactured. An OSH Park order is kind of like a group buy. They take user uploaded designs, group them onto larger panel and send them off to get fabricated. This greatly reduces the cost for small production runs. With this and subsequent orders, I continue to be completely satisfied with OSH Park and their PCB quality. See my review for more about the OSH Park process.
The USB Breakout can be built in a few different configurations. The single rows of headers on either side of the board can be soldered on the bottom for use with a solderless breadboard, on the top as test points, or omitted completely. The optional single-row headers make the board easier to use and a little more versatile.
It took a bit of trial and error but the current version of USB Breakout has turned out to be a handy little tool. The small size makes it a little hard to work with sometimes, but it keeps the cost down (less than $10 for 3 PCBs). There’s a few things I’d do different if I had to start all over again, but I learn better with a little pain and failure along the way.
I posted the schematic and Gerber files to GitHub (https://github.com/TechUnboxed/USBBreakout). If you want to get a set of boards, zip up the Gerber's and upload them to OSH Park.
Bill of Materials:
USB B Receptacle
USB A Receptacle
2 Row, 8 Position Breakaway Header
Single Row, 36 Position Breakaway Header (enough for 3 boards)
4 x 0.1" pitch jumpers (I have hundreds of these scavenged from old PC circuit boards)
UPDATE: The USB Breakout Board is a shared project on OSH Park. Boards can be ordered directly at http://oshpark.com/profiles/Ktulu
|An early USB Breakout in action with an Epic Re:Load|