Quite new to this but making pretty good ground. I have an issue I'm not sure how to solve. I want to add a Pro Micro to an RC Toy, I can easily power it from the toys GND and 5V power. But then I want to use the voltage going to an LED on the toy (uses a different ground) to trigger an event within the Pro Micro.
I can power the Pro Micro from USB and and accomplish what I need with AnalogRead(). But if I connect the GND from the toys main power input to the GND from the LED it no longer acts as it should. I'm thinking these GNDs are not common, or are a separate circuit.
What I'm wanting to know is.. I'm using PIN10 on the ProMicro for the AnalogRead(), can I make it so that maybe PIN11 is the GND for that reading?