Don’t know if this can be made, on amature level.
I want to measure status of a battery . So when the battery is going below ex 18v it’s sending a signal to a dc motor To start to open a door.
And this battery sensor need to Be wireless, and using a battery to power it. Or if I can change the output on the 18v battery to run it.
I hope this make any sensex if not let me know and I will try again:)