Arduino IR LED Transmitter Circuit

This project sends IR signals using Arduino.

Arduino drives one IR LED.

We press button on serial monitor or code trigger.

IR LED sends coded light signal.

This Arduino IR LED Transmitter Circuit works like a small remote controller.

Circuit is easy and simple.

Arduino Coding:

#include <IRremote.h>

int irPin = 3;
IRsend irsend;

int b1 = 6;
int b2 = 7;
int b3 = 8;

void setup() {
pinMode(b1, INPUT);
pinMode(b2, INPUT);
pinMode(b3, INPUT);
}

void loop() {

if (digitalRead(b1) == HIGH) {
irsend.sendNEC(0x00FF30CF, 32);
delay(400);
}

if (digitalRead(b2) == HIGH) {
irsend.sendNEC(0x00FF18E7, 32);
delay(400);
}

if (digitalRead(b3) == HIGH) {
irsend.sendNEC(0x00FF7A85, 32);
delay(400);
}
}

Coding Explanation:

• Library IRremote is needed for sending IR.
• It handle the IR LED.
• irPin is pin 3 for IR output.
• Buttons come on pin 6, pin 7 and pin 8.
• pinMode make them input pins.
• Loop keep checking button press.
• If button 1 is press, send code 00FF30CF.
• If button 2 is press, send code 00FF18E7.
• If button 3 is press, send code 00FF7A85.
• All codes are 32 bit.
• delay stop fast repeat.
• IR LED blink with coded light.
• Device receive it same like remote button.

Circuit Working:

Parts List:

Arduino pin gives digital signal.

Signal goes through resistor.

Resistor protects IR LED from high current.

IR LED flashes at fast speed.

This flash carries IR code.

Receiver device reads this code.

Buttons are simple input switches.

Arduino reads switch press.

Then Arduino sends different IR signals for each button.

Formulas with Calculation:

Below is the LED current formula:

I = V / R

If Arduino gives 5V.

IR LED drop about 1.2V.

Voltage across resistor = 5 – 1.2 = 3.8V

Our circuit resistor is 220 ohm:

Current = 3.8 / 220 = 0.017A

Current is about 17mA which is safe for IR LED.

How to Build:

To build a Arduino IR LED Transmitter Circuit follow the below steps for connection:

• Take all the parts as shown in circuit diagram.
• Connect IR LED anode to R1 one resistor end.
• Connect R1 resistor other end to Arduino digital pin 3.
• Connect IR LED cathode to GND.
• Each resistors R2 to R4 one end go to 5V and other end go to Arduino pins 6, 7 and 8.
• Each switch S1 to S3 one end go to resistors R2 to R4 and other end go to GND.

Conclusion:

This circuit sends IR signals like a simple remote.

Buttons choose which code to send.

Arduino drives IR LED safely using resistor.

This Arduino IR LED Transmitter Circuit is small, cheap and useful for learning IR communication.

References:

IR Transmitter Schematic Review