D1 Mini Shield

Published on 2019-07-15 in PewPew FeatherWing.

I have been mostly working on the PewPew Standalone recently, but some people still prefer the PewPew Lite version, mostly for its color display and ability to work with the ESP8266 Feather. So after I finally found reasonably tiny buttons for D1 Mini UI Shield , I decided to also make a version of the PewPew Lite in form of a D1 Mini shield. As an additional challenge I wanted to make it electrically identical to the FeatherWing. After two nights, I had the design:

It’s not perfect. Ideally, all the resistors would be under the LED matrix, but there simply wasn’t enough room to fit all the traces there. But I managed to do it, even if it required a thousand vias. I ordered the PCB from OSHPark , and promptly forgot about the whole thing.

Today the boards came, so I assembled one. I found a bi-color matrix in my drawer, but I only found 3 of the buttons — I’m still waiting for the package with more of them. So I only soldered what I had, to test how the menu works:

Since CircuitPython no longer supports ESP8266, I had to port the Pew library to MicroPython — that was easy enough, with just changing all the timing functions to use utime, and all i2c calls to use the machine module. After I did that, I wanted to upload the code to GitHub, but discovered that it’s already there — I have ported it once already and forgot about it.

Once the missing button arrive I will finish this.