How to Make a Simple Arduino-Based Motion Sensor Alarm That Will Keep Your Belongings Safe

Making a motion sensor alarm with an Arduino is a great way to keep your valuables and belongings safe. With just a few simple components, you can build an alarm that will detect movement and sound an alarm. Here is a step-by-step guide on how to make your own Arduino motion sensor alarm.

What You Will Need

Here are the components you will need to make the motion sensor alarm:

• Arduino Uno - The brains of the alarm that will control the sensor and alarm
• PIR motion sensor - Detects motion and sends a signal to the Arduino
• Buzzer - Sounds the alarm when motion is detected
• Breadboard - Used to easily connect the components
• Jumper wires - For making connections between components
• 9V battery - Power source for the Arduino

Optional Components

• LEDs - For indicator lights
• Resistors - For controlling current to LEDs
• Enclosure - For housing the alarm circuitry

How It Works

The PIR motion sensor is the key component that allows the alarm to detect movement. It works by detecting changes in infrared radiation levels caused by motion.

When the PIR sensor detects movement, it sends a HIGH signal to the Arduino's digital input pin. The Arduino is programmed to turn the buzzer on when it receives this signal.

The buzzer will sound until motion is no longer detected. An LED indicator can also be connected to show when motion is detected.

Step-by-Step Build Instructions

Follow these steps to assemble the motion sensor alarm circuit on a breadboard:

1. Connect the PIR motion sensor

• Connect the power pin (+) to 5V pin on Arduino
• Connect ground pin (-) to GND on Arduino
• Connect output pin to digital pin 2 on Arduino

2. Connect the buzzer

• Connect positive leg to digital pin 3 on Arduino
• Connect negative leg to GND on Arduino

3. Connect indicator LED (optional)

• Connect positive leg to digital pin 4 on Arduino through a 220 ohm resistor
• Connect negative leg directly to GND

4. Supply power

• Connect Arduino to computer via USB cable, or power with 9V battery

Loading the Code

With the circuit complete, it's time to load the Arduino sketch that will control the alarm.

1. Download the MotionSensorAlarm sketch here
2. Open the sketch in the Arduino IDE
3. Verify and upload the sketch to your Arduino board

Once uploaded, the alarm will be ready when motion is detected by the PIR sensor. The buzzer will sound and the LED will light up.

Testing and Using Your Motion Sensor Alarm

Once assembled and programmed, your motion sensor alarm is ready to use!

To test it, simply wave your hand in front of the PIR sensor. The buzzer and LED should activate.

You can place the alarm near valuables or belongings you want to protect. Position the PIR sensor so it has a good view of the area to detect intruders.

Adjust the sensitivity as needed to reduce false alarms. Add an enclosure for housing the electronics and battery.

With this simple Arduino motion sensor alarm, you can easily keep your important belongings safe and sound an alarm when disturbed. Adjust and enhance it to suit your needs.