ABOUT THIS PROJECT

In this project we’ll modify a commercial motion sensor (powered with mains voltage) with an ESP8266 to log data whenever motion is detected. The data will be sent to Node-RED using MQTT communication protocol. The ESP8266 will be powered through the motion sensor phase out wire using the HLK-PM03 AC/DC converter.

Prerequisites

Here’s the imported flow. It receives the ESP8266 MQTT messages and logs the time whenever motion is detected.

We’ve also added two buttons to clear and refresh the log.

Before continuing with this project, we recommend taking a look at the following resources:

Getting Started with ESP8266 WiFi Transceiver (Review)

Power ESP8266 with Mains Voltage using Hi-Link HLK-PM03

What is MQTT and How It Works

You need to have installed in your Raspberry Pi: Node-RED,Node-RED Dashboard, and Mosquitto MQTT broker

ESP8266 GPIOs and Pinout Reference

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

Node-RED Dashboard

After making all the necessary changes, click the Deploy button to save all the changes.

Now, your Node-RED application is ready. To access Node-RED Dashboard and see how your application looks, access any browser in your local network and type:

http://Your_RPi_IP_address:1880/ui

Demonstration

Now, you can test your project. Whenever motion is detected, the ESP8266 powers up and sends a message via MQTT to Node-RED.

If you go to your Node-RED Dashboard you can see all the logs of when motion was detected. Your application should look as in the following figure.

The dashboard shows the last time motion was detected and all previous logs. You also have the option to refresh the log, and clear the log. Please note that clearing the log is irreversible.