So I'm building up an portable alarm circuit and I'm looking for a secure way to turn it on/off
Originally I looked at Reed switches but these appear to just look for any magnet, so not really secure enough.
I'm now thinking RFID is the only way to go (I want to avoid button pressing), but was wondering if anyone else has any suggestions?
Also I've sourced a RFID reader (RFID-RC522) and it's unclear what ma it operates at. Reading the datasheet the peak of 30ma would deplete my battery in under a day but if it waits for a card in it's sleep state that wouldn't be a problem (it uses minimal UA in this state). Anyone got any experience with these?