I got a problem - I am sending telemetry data to my RC with arduino, and it worked. Until I added a voltage divider to measure battery voltage - I learned in a fiery way that RC motor ESC has no common ground on battery and RC receiver side, and connecting them results in burning cables and smoking ESC. So, I now need to find a solution how to separate the Voltage measurement of battery voltage and the telemetry sending. I thought of following solutions:
- (Opto-) Decoupled voltage measurement sensor - I cant find such thing, but maybe someone could suggest me a solution?
- Decoupling telemetry comm. It is a duplex serial comm, so not too easy to decouple. Maybe there is a simple solution how to decouple a bidirectional serial wire?
- Using two arduinos (I use dirt cheap pro minis from china, and I have alot of them), one in voltage measurement ("Measurement"), fed with a DC-DC stepdown buck from the LiFePo4 battery (9.9V), and another fed from the telemetry/receiver circuit ("Telemetry"). Using optocoupler for one-way communication between them. Actually I just need to shove 1 integer every second only one way. Which way of comm would you prefer here? I2C is bidirectional, and probably complex to isolate, would you use simple RX/TX? Would it work just connecting RX of Telemetry Arduino with TX of Measurement Arduino via optocoupler?