I am wanting to build Arduino circuit to check to see if another Arduino is still alive. How would I do this?
Device 1: Hooked up to a non-battery power-source. Device 2: Hooked up to a battery.
I want to use Device 1 to find out when Device 2 shuts off because of the lack of battery.
I want Device 1 to report to the Serial output (via usb) to deliver this notification.
I can think that I could use a relay, but I don't want to use something that takes any (or almost no) power, plus I want to put Device 2 to sleep every so often.
Could I somehow connect a transistor?
Any options and ideas would be wonderful!