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.

1 x Circuit Playground Express
with CircuitPython
1 x Micro servo
with servo arms
1 x 3 x AAA Battery Holder
with On/Off Switch, JST, and Belt Clip
1 x Rare Earth Magnet
high strength
1 x Magnetic Pin Back
with foam tape

Materials & Tools

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.

This guide was first published on Dec 11, 2017. It was last updated on Apr 17, 2024.

This page (Overview) was last updated on Mar 08, 2024.

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