door-alarm

This is a simple, home-made door alarm based on ultrasound sensor distance measurements

The peripheral device is powered by a Raspberry Pi Pico W, with the following diagram

It works by pointing the ultrasound sensor at the door from the side, the device being placed on the doorframe. While the door is closed, the distance will be 1-5 cm, when the door opens, the side of the door will move, and the distance will be greater the more you open the door, at a 90 degree open, the distance will be the width of the door

After getting the distance and comparing it to the threshold, the peripheral sends updates to the server, which may or may not send a notification to gotify based on whether the door is locked (on the server)