Introduction: IR Home Automation on DFRobot's Relay Shield

Use DFRobots 4 Channel relay shield and control up to 4 appliances using just a infrared remote controller.

Everyone wants a remote to control all the appliances in your home. Some companies are introducing wireless controllers for various appliances but they are costly and you have to upgrade the existing for additional cost. So, what about making your own home automation system to control up to 4 appliances.

Step 1: The Things You Need

Hardware components:

  1. Arduino UNO Rev 3
  2. 4 Channel Relay shield
  3. IR Kit for Arduino

Software apps and online services:

  1. Arduino IDE

Step 2: Specifications

4 Channel Relay Shield

  1. Compatible with Arduino UNO Rev3
  2. 4 buttons to test module
  3. LED status indicator of relay
  4. Support Xbee IO directly control
  5. Xbee socket for wireless communication
  6. Selectable digital IO pin for control(Default digital 2,7,8,10)
  7. 6 channels Analog IO & 13 channels Digital IO
  8. Up to 4 Relay with photo-coupled circuit
  9. Contact Rating : 3A AC 120V / DC 24V
  10. Max Switching Voltage : AC 240V / DC 60V (Less than 38V is recommended)
  11. Max Switching Current : 5A
  12. Max Switching Power : AC 360VA / DC 90W
  13. Electrical Life (Min) : 100,000 Operations
  14. Mechanical Life (Min) : 10,000,000 Operations
  15. Safety Standard(relay) UL cUL TUV CQC
  16. Coil Working Voltage 9VDC
  17. Working temperature -30℃ to +85℃
  18. Working Humidity 40% - 85%
  19. Size: 95x65mm

Step 3: The Working

High Voltage VS Low Voltage

We all know that the appliances work on 110 V (USA) and 220 V (Asia)depending upon the region. But, the Arduino we are using is working on just 5 V. If we connect it directly to the mains supply to control the appliances just like controlling the LEDs, the board or the microcontroller will get burned. So, we use 5 V relay which works as an interface between the two voltage supplies. A signal is sent to relay by Arduino and relay switches on the circuit of the appliance.

Wireless Transmission of Data

We know that how will we switch the supply on but we need to send the signal from an IR remote to the receiver with Arduino. So, we can use any generic IR remote controller available in market. But, every remote controller comes with different codes for their buttons which they send it through IR LED. So, we need to find those codes for a random IR remote controller we are using.

For that, please click here for another project of mine on

Step 4: Hook-up the Circuit

IR receiver and relay connections:

  1. Just stack the relay shield on the Arduino board.
  2. On the shield, there are male headers for digital I/O pins.
  3. Connect the connector cable for IR module in the PIN 11 of the board.
  4. Keep in mind the colors on the wires matching with each other.

Step 5: Testing It Up!

Remember to install the IRremote.h library in the Arduino IDE. Download the ZIP File.

  1. Upload the code attached in the end of project.
  2. Wait for the system to initialize.
  3. Now, press the POWER button to switch ON/OFF all the appliances.
  4. Press each corresponding button (like 1 for fan, 2 for light and so on) to switch ON/OFF them.

Step 6: CODE