Infrared Security System

Project 13 out of 18

Build an alarm system to sound when someone walks by.

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Continue the Electronics Course and make an Infrared Security System that can detect motion through body heat. You’ll learn all about PIR sensors, or passive infrared sensors and how you can use them as part of your Security System. First, assemble the hardware, making sure each part is in its correct position on the breadboard. Then, you’ll figure out how you can make the sensor more accurate by adjusting the sensitivity potentiometer. After, you’ll learn about implementing the modulo into your C++ program. Once your Infrared Security System is detecting intruders, figure out how to make it more complex with extra challenge exercises.

Milestones Unlocked



Programming (C++)

PIR Sensors

Modulo Operators

Course Progression

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Lesson Preview

Put your understanding of your Infrared Security System project to the test with these challenges:

  • Make the alarm pattern more than two notes.
  • Make the alarm wait longer before arming.
  • Make the LEDs flash when the alarm goes off.
  • Require the alarm to be triggered twice before it sounds.

Electronics Course


18 Projects


Ages 12+


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