There are many gadgets for locking out there: August, Kevo, Yale, Igloohome, etc just to name a few. They generally cost more than a hundered bucks and not very customizable.

A reference design for a custom use-case? Not so much. Enter the ESP32 microcontroller (MCU), a low cost and easily programmable (with the Arudino IDE at least) MCU with built-in WiFi and many other features. You can easily find a module with user-friendly pinouts for under ten bucks online!

The module used is kind of an overkill, but that is how cheap such things have gotten over time.

I gave a talk about the process, at the Hackware 3.7 event in Singapore back in 2017.

Hardware: CAD, 3D printing

Software: C/C++