20ch Servo Shield Assembled

Published on 2017-01-20 in Servo Breakout for WeMos D1 Mini.

It took some time, but the 20-channel version of the D1 Mini servo shield is finally assembled. I still used an ATmega328p, because that’s what I have on hand (the code is now small enough to work on an ATmega8). As you can see on the picture below, the angled headers make it stick out of the D1 Mini outline a little bit – but now you can really stack them! Once I update the firmware to take into account the address selection jumpers, you will be able to stack four of those babies, giving you a total of 80 servos to control. Of course powering that many servos from the poor D1 Mini is a bad idea (unless most of them only move sometimes), so you can also cut the trace connecting the 5V power with the D1 Mini pin, and provide the power separately.

Of course, as soon as I got the PCB in my hands, I immediately got some ideas on how to improve it: connect the reset pin to the D1 Mini’s reset pin, for easier programming and to make them both reset together, make the D1 Mini outline on the top of the board smaller, so it’s more readable, etc. – but those are small things, and I’m mostly happy with this version.