Need a Loud Electrical Component for Magnetic Lock
Use a linear solenoid and a bell.

It will work with the same principle holding your door locked. The pull-type solenoid will hold the plunger down while the power is on. When the power is disabled, the plunger is released and sprung forward to strike the bell. When the lock is reengaged, the plunger is pulled down ready to strike the bell again.



Ding.