Introduction: Automatic Air Conditioner Switch

Since there are various different things that people need to do during their daily lives, we often forget some minor details, sometimes causing severe consequences, forgetting to turn off the air conditioner is one of them. While people accidentally forget to turn the air conditioner off, the electricity bills for next month will increase rapidly. Therefore, it would be nice if a device could turn on the air conditioner when you enter the room, and turn it off when you left. Our device will be able to achieve that goal with simply an Arduino board and several common household items.


- Arduino Uno/Leonardo x1

- Breadboard x1

- Tape x1

- Air Conditioner Controller for Operation x1

- Servo Motor x1

- Jumper Wires x4

- Photoresistor x1

- Resistor x1

- Arduino Wire Extension Cord x3

Step 1: Prepare All Your Materials

(1) Jumper wire

(2) Photoresistor

(3) Servo Motor

(4) Arduino Leonardo & Breadboard

Step 2: Build the Circuit

The circuit should look like the images above after adding wires.

For Specific Wiring:

D10 -> White wire of the servo motor (connect them with an extension cord)

A0 -> A46

+55 -> D47

+61 -> 5v

-23 -> Black wire of the servo motor

+23 -> Red wire of the servo motor

GND -> -36

Resistor: (1) D46; (2) -43

Photoresistor: (1) E47; (2) D46

Step 3: Apply the Device on the Controller

Place the servo motor on the air conditioner controller, the spinning wheel on the motor should be appressed tightly on the power button of the air conditioner so that it could function properly. After that, apply tapes on the air conditioner controller and the motor to prevent the motor from falling off. Finally, cover the tape and the motor with things such as a cloth, a box, or a paper to decorate.

Step 4: The Code

Step 5: Done

After the device is completed, the air conditioner should be able to turn on automatically when turning on the lights like the video below: