Soo, I'm having some electrical problems and I can't figure out why.

I can get 3 wheels to turn but the front right won't move. 

I might have burned out the L298N motor controller. So I'm gonna have to start over with the wiring setup. 

Currently I have a huge mess of wires that's hidden under a plastic box from a yogurt container. Its time to get into that mess and figure out where the problem is.

Luckily I have a volt meter and a small oscilloscope!

I have also discovered that the encoder library which I want to use requires that you connect the encoders to pins with interrupt capability. The uno has only 2 pins like that and I need 8, since I have 4 motors with A and B signals. So I have decided to switch to an arduino mega. It has way more pins so maybe I can also get rid of the shift register.

So the plan is to trouble shoot the electrical stuff, switch to a mega, and setup up the encoders.

 

Currently I was not able to establish how many ticks the encoders provided per rotation, the results were just too inaccurate.

I have also switched to a raspberry pi 4 because as it turns out the 3 A model didn't have enough ram.