I'm working on a project where users unlock lockers programmatically (with a password), however in case of power outage or equipment failure keys need to be available, but are only supposed to be used in those 2 situations.
I'm trying to setup an "Alert circuit" which is triggered whenever a key is used (even when unpowered), but can only be turned off by the proper user entering their password and turning the alert off. While not high security, I think this will be sufficient. Does anyone have any ideas for components to accomplish this in a simpler way than what I outline below?
The one way that I've come up with would be tricky mechanically and probably pretty finicky. I would have a switch that is spring loaded to hold a gap closed, and a solenoid that is spring loaded to open between the gap in the switch whenever a key is used (which depresses the switch and opens the gap. When the solenoid is expanded into the gap the switch is unable to close and the "Alert" is set, even without power (as soon as repowered the alert light is blinking). In order to reset and turn off the alert, the user must enter their password, and press a reset button which pulls the solenoid back out of the way momentarily, and the system is ready to detect the next key usage.
I'm trying to setup an "Alert circuit" which is triggered whenever a key is used (even when unpowered), but can only be turned off by the proper user entering their password and turning the alert off. While not high security, I think this will be sufficient. Does anyone have any ideas for components to accomplish this in a simpler way than what I outline below?
The one way that I've come up with would be tricky mechanically and probably pretty finicky. I would have a switch that is spring loaded to hold a gap closed, and a solenoid that is spring loaded to open between the gap in the switch whenever a key is used (which depresses the switch and opens the gap. When the solenoid is expanded into the gap the switch is unable to close and the "Alert" is set, even without power (as soon as repowered the alert light is blinking). In order to reset and turn off the alert, the user must enter their password, and press a reset button which pulls the solenoid back out of the way momentarily, and the system is ready to detect the next key usage.
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