The electronics for the prototype consist of a 3s lipo battery powering some BTS7960 motor controllers and an Arduino UNO. Communication is done through a T8S radio transmitter and receiver. The receiver outputs s.bus which needs to be inverted in order to connect to the Arduino's  uart.

I plan on changing the communication method because the T8S and Arduino are so expensive. But If you'd like more information about how to use S.bus with Arduino, check out this git hub library https://github.com/bolderflight/sbus

So far, I'm a big fan of the BTS790 motor controllers but they're wiring can be a bit of a mess and requiring two PWM signals for inputs is a bit of a mess. I plan on creating an interface board to simplify the wiring. But until then, checkout this tutorial for how to wire them to an Arduino https://electropeak.com/learn/interfacing-bts7960-43a-high-power-motor-driver-module-with-arduino/

I used a power distribution board from a previous project, plan to redo to include some fuses for over current protection. https://hackaday.io/project/188503-fpv-robot/log/215442-a-sweet-new-power-distribution-boardthanks-pcbway

Biggest problem with the prototype electronics: no main power switch :(

Total Electronics BOM: $117.99

Doesn't include wiring or shipping or connectors.

Biggest cost sinks right now are the Arduino and transmitter/receiver. I plan to switch to using wifi+esp32 for communication which should significantly drop cost.