PewPew 3.0 Standalone

Published on 2017-09-23 in PewPew FeatherWing.

After my last experiment with the homebrew Trinket M0, I designed and ordered a board for PewPew that has its own Atmel SAMD21E chip on board. It arrived today, and i assembled it and it seems to be working! I was able to flash the UF2 bootloader and CircuitPython on it, and to light up a couple of pixels on the display — I still need to re-write the pew.py library for this platform. I’m especially worried about button handling, since CircuitPython doesn’t have any interrupt support. In the worst case I might need to write the library in C and compile it into my own fork of CircuitPython.

If it does come to that, I will probably also remap the pins, to use ones not available on the Trinket, and to free up the DAC pin for sound — adding a small amplifier and speaker would be great then. For now the design is a little bit random, and I had to add one wire where I missed a pull-up resistor. I expect to make more versions, and to gradually clean up the design and arrange all the elements properly.

I’m also not happy with the location of the USB port, and generally with how you touch the elements with your fingers while holding this. I might actually get back to the “sandwich” design with two PCBs, so that the back of the bottom PCB could be completely clean of components, and the battery could be hidden in between.