Tiny ATtiny84 PCB Tester

I designed and sell a small PCB called the EZ Fan 2, which is assembled and shipped to me untested. While failures are quite rare, I still like to verify things are assembled correctly, so rather than (continue to) hook the boards up to an actual Raspberry Pi and fan, I came up with this ATtiny84-based test fixture.

The device's design is simple, passing a blinking signal from the '84 to pogo pins arranged to fit the EZ Fan 2. This is facilitated by the "EZ-85" ATtiny breakout board featured here, which has outputs specifically designed to accommodate the PCBs under test. A CR2032 coin cell battery powers the unit. Given the ATtiny84's low power requirements, plug intermittent usage, it should last for a very long time.

Perhaps the most generally interesting bit of this project is the mechanical arrangement of the pogo pins, as explained around the 2:00 in the video. First, when all pins are bottomed out in the 3D-printed fixture, they're automatically set at the same level for testing. Two of these pogo pins need to connect with an LED, but instead of using solder, the print and spacing allows the leads to bend and act as a spring. This retains both the LED and pogo pins, and would allow them to be easily changed out if needed.

While it's questionable whether or not this project took me more time than it will save over the long run, now that it is done, testing is a snap. I enjoyed building it, and learned a few things along the way, so I'd certainly consider it a success!