A DIY intruder alarm can be built with inexpensive parts like a PIR motion sensor, buzzer, and Arduino or ESP32 board.
How It Works
The motion sensor detects movement, the microcontroller triggers the buzzer, and (optionally) sends an alert via Wi-Fi or Bluetooth.
Basic Components
- PIR Motion Sensor
- Arduino/ESP32 board
- Active Buzzer
- LED Indicator (optional)
Simple Wiring Concept
Sensor OUT → D2
Buzzer + → D9
GND → GND
VCC → 5V
Once built, you can upgrade it with SMS alerts or integrate it into a larger home security setup.