"Mechanical On/electronic off" switch component

Look into a relay, not a solenoid.

 

I don't understand your description of your idea. Perhaps you could draw it up and scan the drawing and post it here.

I'm also not clear on what you want to do.

So you have lockers that can be unlocked electronically (through a solenoid of some kind) but you also need to be able to unlock them with a physical key if the password is lost or power has failed. And you want some method to detect when the key has been used, and raise an alert after the key has been used until the correct password is entered. Is that right?

So the system that detects the use of the mechanical key needs to operate without power? So it needs to be mechanical? I guess it could be mechanically activated by the key barrel, and mechanically reset by the solenoid? And the system wouldn't be able to raise an alarm until the power was restored.

What happens if the password is lost permanently? How would you be able to reset the alarm condition and set a new password? These are important functions of the electronic lock controller, and I think you need to describe that in a lot more detail and/or give a link to a URL for it, if it's a commercial product.

I'm just thinking out loud and trying to clarify your requirements. I think you need to get into a lot more detail in your posts. Also remember that we're mainly electronics people - at least I am, so we may not be familiar with the mechanical options available.

 

How long is your longest power outage? Could you arrange a capacitor such that it is charged when the power is on and discharged only when the key is used? Then on power-up of the lock controller you could check for charge in the capacitor.

 

If this is a new design and you are making the hardware too, it could be very simple.

If you use a bolt type lock, the key could release a lock flap on the door, and the door can be opened. It can not be closed again since it will be stopped by the bolt and stay open to the lock bolt is activated to open again. The alarm is just a magnetic door switch, which state is combined into the logic of the lock controller.