I noticed I have a power drain through the RX pin. My sensor has 3.3v directly from the pin, and I disconnect it through a MOSFET disconnecting the ground. However, I notice that the RX still has some power to it, which I think is causing my power drain.
If I put the RX pin into output mode, will that remove the power drain? Then I can turn it back to input mode before reading.
Why do you think that is causing your power drain? How are you measuring your power? It would be helpful to see how you have things wired up.
I think I fixed it, I didn’t set the pinMode(RX, INPUT) in the startup. I think it was the power drain, because it is the only line with power on it and if I disconnected it from the RX pin, then my battery doesn’t drain.
3.3 -> Sensor +
B0 -> mosfit
Sensor TX -> Particle RX.
Sensor ground -> mosfit
Mosfit -> Particle Ground
Just for nit-picking - it’s a MOSFET (metal oxide semiconductor field Effect transistor).
If you never called
Serial1.begin() the RX GPIO will be in Hi-Z (INPUT) mode by default. And when you want to deactivate the interface call