Here is a box I designed with a sliding toggle mechanism. Sliding the toggle to one side locks the box and reveals ON, meaning the lock is engaged. Sliding it to the other side unlocks the box and reveals OFF. ( I also made another toggle with a more obvious LOCK / UNLOCK label).

I know the design is a bit over-engineered, but that was intentional. I wanted it to be simple and elegant, while still being practical and satisfying to use. One of the main goals was to make the lid fully reversible, so it can be placed on the box in either direction. To achieve that, I designed the mechanism to be perfectly symmetrical for easier everyday use.

Caution: when printing the box, make sure to use supports, preferably tree supports for easier removal. Otherwise, the mechanism may not print properly or work as intended.

Assembly should be pretty straightforward. Just use the image showing the inner structure as a reference and it should be easy to put together. The pins in the corners are meant to be a loose fit to help prevent buckling. If you want an even more secure fit, you can use a small amount of glue.

Enjoy :)

https://www.starryodyssey.com/design/toggle-lock-box