I’ve been tinkering with an idea for implementing a rfid lock for my electric scooter using the xEM. They sell an oem fingerprint lock which appears to simply connect two pins on the controller, if no lock is installed, there’s just a jumper in place which always shorts the pins. Unfortunately, in researching what kinds of technology I need to get to create the lock, I accidentally found out the pins are 60-100V DC and had a bit of a surprise with a large spark and pop, followed by magic smoke (pretty sure I shorted pins with my multimeter that I did NOT intend to).
So, I know I’ll need a vreg to bring down the 100V to the 12V the xEM runs on. My original plan was to have the signal line of the xEM trigger a relay, then have the output of the relay hold the input open with a diode to protect the signal line from not having >12 volts sent down it, but with the high voltage I’m a bit concerned. I’ve been looking at ratchet relays but I’m not 100% certain what to get or where to get it. Could someone with some more experience in electronics work give me some advice? (The pinout of the lock header appears to be Unused, V+, Ground, Lock Trigger)