You can build a working combination dial safe using the Circuit Playground Express, a servo motor, a box, and a few magnets, wires, and batteries!
The Circuit Playground Express has everything we'll need to act as a dial that measures rotation, can give feedback through colored lights and sounds, and even control the lock!
You'll be able to code it all in CircuitPython, including reading the built-in accelerator, setting a custom combinations, and more! Plus, you don't need any compilers or IDEs, just a text editor and a USB cable to connect.
You can use any lidded box of your choosing, but a really good choice is the black, cardboard Adafruit box!
The only tools you'll need are a small Philips screwdriver and some Scotch tape. Optionally, you can use a silver or white marker to decorate your safe.