AI Matt

Robotics blog

Arduino Burglar Alarm With SMS

I made a simple Arduino project, using a motion sensor and the TelAPI web service to send me an SMS when motion (cat/burglar/child) triggers the Arduino. You can view the source at

Arduino SMS Alarm

An Arduino based burglar alarm that sends an SMS when motion is detected. It will send an SMS to you every 30 minutes while motion is detected (configurable).


PIR Sensor

Set up

Wire it up!

  1. Attach + on the PIR sensor to 5v on the Arduino
  2. Attach - on the PIR sensor to GND on the Arduino
  3. Attach OUT on the PIR sensor to DIGITAL 2 on the Arduino

Schematic Wired Up

Upload the sketch

  1. Plug your Arduino into your computer
  2. Open the arduino_pir/arduino_pit.ino sketch with the Arduino IDE
  3. Select your serial port (Tools>Serial Port) and click Upload

Your arduino LED will now be blnking. This means the PIR sensor is calibrating.

Setup the server

  1. Open with a text editor
  2. Change the value of SERIAL_PORT to the serial port you set in the Arduino IDE. For Windows it might look like COM2, for Posix systems, it might look like /dev/tty.usbserial-AH00PP05
  3. Change the value of SMS_FROM to the number in your TelAPI account numbers (You can set this to another number, such as your own phone and it will cost a little extra. This is what I do.)
  4. Change the value SMS_TO to your cell phone
  5. Change the value of TELAPI_ACCOUNT_SID to your Account SID as found at your TelAPI dashboard
  6. Change the value of TELAPI_TOKEN to your Account Token as found at your TelAPI dashboard

Run it!

  1. Open up your terminal and run python (assuming the terminal is CD’d to the directory where is)
  2. The Arduino will blink it’s LED for 60 seconds. Get out of the sensor’s sight while it calibrates.

Now, whevever motion is detected in the infra-red spectrum (think body heat), will send you an SMS up to once every 30 minutes.

Put it in a case (Optional)

  1. Get some plastic case, like one from a hummus & pretzel snack
  2. Cut a hole in the top for the sensor to be exposed (like R2D2 in an X-Wing)
  3. Cut a hole for the USB cable to stick out
  4. Tape or screw the sensor to the top
  5. Finit!

Cut a hole Cut a hole



X-Wing Car

YUM (Makes a nice case)

Sabra Hummus Single Serve

Free $25 credit when you sign up for a TelAPI account!


Nate Kapitanski Miami Florida Nathan Kapitanski Rutland Vermont jammasternate