DIY Human Presence Sensor: Step-by-Step Guide

Have you ever wanted to create your own human presence sensor? With just a few materials and some tinkering, you can make it happen. In this guide, we'll show you how to transform a Mi Home Door Sensor 2 (Bluetooth version) and an LD2410B Presence Radar into a functional human presence sensor. With the ability to control lights, trigger alarms, and more, this DIY project opens up a world of possibilities. Let's get started!

Materials Needed:

1. Mi Home Door Sensor 2, Bluetooth version

2. LD2410B Presence Radar

The radar sensor consumes too much power at 79mA. Calculations show that a single 18650 battery would only last a day or two, so using an external power source is necessary. Xiaomi operates at 3.3V while the radar requires 5V. Since the door sensor's power supply remains unchanged and can last for two to three years, there's no need to modify it or add a voltage regulator, which would increase costs and power consumption.

Disassembling the Door Sensor:

· The top part contains a Hall sensor.

· Removing the Hall sensor is necessary as it improves response time and reduces interference.

Connecting the Signal Lines:

· On the right side, the radar needs to be installed.

Finalized Modification:

· The modified sensor works fine after testing.

Creating Smart Rules for Mi Home to Control Lighting On and Off.

This DIY project has various applications, such as controlling smart switches in a restaurant or serving as a motion detection alarm. If static power consumption is a concern, an additional level of infrared detection can be added, which has lower power consumption. Once a person is detected, the radar can be activated for precise positioning.