
Description:
This recipe will teach you how to use an IR Sensor with the Arduino and you will learn to turn on either an LED or a Buzzer based on whether the sensor is triggered.
Parts:
- Arduino Uno
- IR Sensor
- LED
- 220 Ohm Resisitor
- Buzzer
- Breadboard
- Wires

Code:
#define ir 7
#define buzzer 8
#define led 9
int obstacle;
void setup() {
pinMode(ir, INPUT);
pinMode(led, OUTPUT);
pinMode(buzzer, OUTPUT);
}
void loop() {
obstacle = digitalRead(ir);
if (obstacle == LOW)
{
digitalWrite(led, LOW);
digitalWrite(buzzer, HIGH);
}
else
{
digitalWrite(led, HIGH);
digitalWrite(buzzer, LOW);
}
}
Code language: PHP (php)
Code with Comments:
//Create names for digital pins
#define ir 7
#define buzzer 8
#define led 9
//Create variable to test against for sensor
int obstacle;
void setup() {
//Set ir pin for INPUT so that it reads from the sensor
pinMode(ir, INPUT);
//Set led and buzzer to OUTPUT so that they can be turned on/ off
pinMode(led, OUTPUT);
pinMode(buzzer, OUTPUT);
}
void loop() {
//read from the IR sensor and assign value to obstacle variable
obstacle = digitalRead(ir);
//if IR Sensor detects something then turn buzzer on, and led off
if (obstacle == LOW)
{
digitalWrite(led, LOW);
digitalWrite(buzzer, HIGH);
}
//if IR Sensor does not detect something turn led on, and buzzer off
else
{
digitalWrite(led, HIGH);
digitalWrite(buzzer, LOW);
}
}
Code language: PHP (php)
Extra Credit:
Test IR Sensor with different materials and see if you can touch the sensor without triggering it.
Note: Try electrical tape.