Introduction: 2 Minute PIR Alarm

About: I am robotics engineer and a teacher whose passion in life is breaking down the maths and academic jargon of programming and robotics into something that everyone can understand, primary school kids included.…

Ever wondered how to make a burglar alarm or how to beat it?... well its
all about Passive Infra Red sensors, in other words heat sensors. PIR alarms sense moving heat so the trick is not to breathe and to be dressed like an Eskimo.

The module: HC-SR501 works in a simple manner, basically 2 pins connect to 5V and GND and the third pin goes on when motion is detected.

The rest of the circuit is there to raise the alarm when the PIR alarm pin (pin 6) is on. The alarm is raised by a piezo buzzer in pin 11 and a 5mm LED in pin A0

Components used:

• Arduino Uno

• 5mm LED

• Piezo Buzzer

• PIR Sensor HC-SR501