What type of encoders to use?

[nathan_hui]

You probably don't want to put encoders directly on the axles of the wheels. For one, I'm guessing you're using the kit chassis, which would mean idle axles. Ideally, the encoders for the kit chassis would go on the backside of the Toughbox.

For the pinout, you'll have to modify the pins anyhow. The E4P has +5V,A,GND,B, but that needs to be split into two 3 pin connections (GND, +5V, A) and (NC, NC, B) in order to interface with the Digital Sidecar. You'd need to do the same or similar for the E2 and E6 encoders (ignore the index channel).