Infrared Sensor¶

Working principle: Reflection of light

Uses¶

• Obstacle detection
• Differentiate between colors

Components¶

• Transmitter: IR LED
• Receiver: Photodiode (Reverse LED)
• Comparator IC for voltage comparison
• Potentiometer to set sensitivity of sensor, by controlling voltage threshold for comparator
• \(V_s \ne \{0, V_{cc} \}\)

Working steps¶

1. Transmitter emits IR rays
2. Light gets reflected by obstacle
3. Receiver gets the reflected light
4. Received light converted into voltage

Limitations¶

• Cannot obtain position of obstacle; only for Object-Detection (binary)
• Obstacle detection only works for light-colored obstacle
• dark colored objects will absorb light

Circuit Diagram¶

Code¶

int objected_detected

void setup(){
  pinMode(D1, INPUT);       // sensor
  pinMode(D2, OUTPUT);  // output device (LED)

  Serial.begin(9600);
}
void loop(){
  objected_detected = digitalRead(D1);

  Serial.println(objected_detected);

    if (objected_detected == 1) {
    digitalWrite(D2, HIGH);
  } else {
    digitalWrite(D2, LOW);
  }

  delay(500);
}

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