Parts Required:

Here’s a list of the parts needed for this project:

PIR Motion Sensor 220V (or 110V PIR Motion Sensor)

ESP8266-01 – read Best ESP8266 Wi-Fi Development Boards

ESP8266-01 Serial Adapter (to upload code to the ESP8266)

Hi-Link HLK-PM03 (to convert mains voltage to DC 3.3V)

Small protoboard

Fuse Slow Blow (200mA)

47 uF electrolytic capacitor

Raspberry Pi (to host Node-RED and MQTT broker) – read Best Raspberry Pi Kits

Project Overview

This project is divided into three parts:

Building the circuit

Writing and uploading the arduino code

Creating the Node-RED flow

Motion Sensor

We’ll hack a commercial motion sensor that has enough space to put an ESP-01 and the HLK-PM03 AC/DC converter module inside. We bought our motion sensor for $5 in a local store.

When the PIR sensor detects motion, there’s power coming out from the red hot wire that can turn on a lamp or a device. Your motion sensor should have a similar wiring diagram on the lid or printed in the instructions manual.

The HLK-PM03 module AC/DC converter supplies 3.3V from either 110VAC or 220VAC. This makes it perfect to power the ESP8266 from mains voltage.

In summary, when motion is detected there is power reaching the arduino. The arduino can execute tasks for as long as the motion sensor is triggered.

You may need to adjust the time duration that the sensor stays on, so your ESP8266 has enough time to execute its tasks. The sensor should have a knob to adjust the time (and another to adjust luminosity).