Build Your Own Smart Motion Detector That Actually Works! (ESP32 + PIR Tutorial)

Mounir — Mon, 24 Feb 2025 13:57:09 +0000

Want to protect your home with a DIY solution? Create your own smart motion detector that works as effectively as commercial systems. Perfect for beginners in IoT and home automation!

What You'll Create:

A reliable motion detection system that sends instant alerts
Your own IoT device that works with smart home platforms
A professional-grade security sensor you built yourself
Automated email notifications when motion is detected

Prerequisites :

Active AskSensors account: Create AskSensors account.
Create a new sensor. Follow the simple process described here.

Required Hardware:

ESP32 board
PIR motion sensor
Jumper wires
1kΩ resistor
Breadboard
Micro USB cable

Quick Assembly:

Connect PIR VCC → ESP32 5V
Connect PIR GND → ESP32 GND
Connect PIR DATA → ESP32 GPIO2 (with 1kΩ resistor)

Note: The ESP32 GPIOs require 3V3 signals (not 5V tolerent). For quick hack, you can only add a serial resistor of 1K between the PIR DATA pin and the ESP32 GPIO pin to protect the ESP32 GPIO from damage. However, for production, a 5V/3V3 level shifter is needed to guarantee long term circuit reliability. You can check this page to get a 5V/3V3 level shifter module.

Setup Instructions:

1. Prepare Your Environment

Install the latest version of the Arduino IDE software (1.8.7 or higher).
In your Arduino IDE, go to File> Preferences.
Go to the “Additional Board Manager URLs” field, Enter the following URL: https://dl.espressif.com/dl/package_esp32_index.json
If you already have the ESP8266 boards URL, separate the URLs with a comma as shown below:

https://dl.espressif.com/dl/package_esp32_index.json,http://arduino.esp8266.com/stable/package_esp8266com_index.json

Now, open boards manager (Tools > Board > Boards Manager), search for ESP32 and click the install button for the “ESP32 by Espressif Systems”.

2. Code

Install the MQTT PubSubClient Library for the Arduino IDE if you haven’t already.
Download this demo from the AskSensors Github page.
The provided code simply reads the status of the PIR sensor and send this information to AskSensors over MQTT. You need to modify the following variables:
Your network credentials, so that ESP8266 can establish a connection with existing network
The Api Key In and username to set the MQTT Topic:username/apiKeyIn

const char* ssid = "YOUR_WIFI_NAME";
const char* password = "YOUR_WIFI_PASSWORD";
const char* username = "YOUR_USERNAME";
const char* pubTopic = "publish/username/apiKeyIn";

3. Upload and Test

Connect ESP32 via USB
Check your Sensor data stream on AskSensors.
You can cross-check the AskSensors graph readings with the values being printed on your ESP32 Serial Terminal.
You can customize a Binary graph to plot your data as showing by next pictures.

4. Configure Email Alerts

Log into your AskSensors Iot platform & select your sensor
Click the 'Add Alert' button
Select 'Email Alert' as the notification type
Set your desired threshold values:
- Choose 'Max Value' = 1 to detect motion
Enter your email address
Save the configuration

Now you'll receive instant email notifications whenever motion is detected!

Perfect For:

Home security
Smart lighting automation
Pet monitoring
Visitor counting
Energy saving
Remote property monitoring

This project takes only 30 minutes to complete and can be a great addition to your smart home security system. With email alerts, you'll never miss any unauthorized movement again!

DEV Community: Mounir