I was considering several different ways to send simple data from one Arduino to another when I though, why not connect a PWN pin of one Arduino to the analog pin on another? I could send simple messages for one to the other by setting different values on the PWM pin. This seems like it would work, except for the fact the the PWM pins mimic voltages with pulses.
Is this a reliable way to link two Arduinos, If I only want to communicate 4 states? Also, will I need to include some additional components in the connection (resister, capacitor, etc.)
All it needs to do is send a 2v pulse for yes and a 5 v pulse for no. It needs to do this about 6 times an hour.