Electric latch for math toys
Spring loading...

You could use a spring loaded drawer mechanism. You can then use a solenoid, servo, or other electromechanical device to release the spring and thereby open the drawer. This is similar to how cash register money drawers work.





How it works:

When you push down on the wooden dowel (pin) at the top, it lowers a catch inside that allows the spring behind the drawer to push the drawer out.



You can make the dowel pressing action electromechanical (EMech) instead of manual by adding a solenoid (there are other ways to do it with other EMech devices).

A solenoid (there are many configurations, the one shown here is the most common) works like this:



When you apply power a central bar will retract into the solenoid housing. When power is removed a return spring will re-extend the bar. The opposite, latching, and bipolar configurations are also available, so be careful when purchasing.

Disconnecting power after activation...

To achieve the final part of your spec, disconnecting power after the drawer opens, you will need to add a limit switch behind the drawer that is Normally Open ("N.O."). When the drawer is closed, the switch arm will be pressed back against the switch body, closing the switch.



When the drawer opens, it will move away from the switch releasing the switch's arm and opening the circuit. This switch must be in series with the solenoid power supply to be effective.

Good luck with your project!

Please note:

Project and imagery by Steven Kirk of Cryptic Woodworks (not me).
https://youtu.be/4GHjI6W6s6M