Failed

The PCB I ordered finally arrived, and I can't believe the amount of failure in it. Of course it's all my fault.

First of all, I used "small" holes for the pin headers, which are fine for female headers, but way too small for male ones. In particular, the pins of the Pro Mini wouldn't get through -- I had to drill those edge holes bigger. Fortunately they are not used for any connections.

Second, if you properly solder the pins, they will stick out a little on the other side of the board, so it won't be flat against the Pro Mini. Which is kinda obvious now. I had to solder them with very little sticking out, which makes them very fragile and easy to bend or break off.

Third, and that's made worse by the previous, the pins of the Pro Mini that actually reach the servo plugs are quite short. In fact, they may be too short for a proper connection.

In conclusion, I consider this project failed, especially since there are two great alternatives now, #SERVOcontrol and #Universal Servo Breakout. However, I will re-use the source code in my projects.