I am not an electrical engineer. I have a basic knowledge but my skills have gone downhill lately and I’m not as sharp as I used to be, and I basically cobble stuff together that I read online. Please double-check my work and if you have comments, please let me know so I can update and correct it.
I am not going to use the Piface HAT. In fact, I may need to multiplex some LEDs since I will be short some GPIO pins. I was thinking MCP23017 I2C I/O extender, but I haven’t done anything with I2C before, much less that chip, and at this point, I need to remind myself to keep it simple, and stop adding features and think about removing some! There is a time limit.