D1 Mini Expander Shield

The PCBs for the larger chips just arrived (just one day after the smaller chips arrived, that was a close race), so now I have both versions:

The big one is slightly faster to solder, but has the jumpers and interrupt pins on the bottom.

I stopped believing that I am somehow competent enough to order the right footprint of the chips, and I decided to simply redesign the PCB to accommodate the bigger chips. When life gives you lemons...

It just barely fits, together with the pullups and a filter cap. I had to move the address jumpers to the bottom, though:

Now working on fitting as many as I can on a 10x10cm board:

This is really annoying...

I feel like this could actually be sold on Tindie, so I added this board to an order I was making anyways. The boards arrived this week, and today I decided it's time to play a bit of a sweat shop and assemble a couple of them. However, this is the only MCP23017 chip I could find in my drawer:

I think it may be the wrong footprint for it...

...you re-discover your unfinished project by looking through order history at OSHPark, then search for the PCBs that must have arrived three months ago, then assemble and test it, and then, when you go to document it at HaD, you find that you already did all that once.

The chips arrived as expected, and I assembled the first prototype. It responds over I²C, so everything seems fine. Now I just need the library.

The prototype PCBs from OSHPark arrived today, but I'm still waiting for the chips. However, I just got an e-mail notification that the package with the chips arrived in my country, so they should get here tomorrow. Of course I will also need a library for this, but it should be trivial.