Build a smart street light that automatically turns ON when it gets dark and OFF during daylight using an LDR sensor. This concept is commonly used in street lights, garden lights, parking areas, and energy-saving lighting systems.
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This logic reads both IR sensors: if the left sensor sees the line, it steers left; if the right sensor sees it, it steers right; if both see black, it drives straight.
const int ldrPin = A0;
const int ledPin = 8;
const int threshold = 500;
void setup() {
pinMode(ledPin, OUTPUT);
Serial.begin(9600);
}
void loop() {
int ldrValue = analogRead(ldrPin);
Serial.println(ldrValue);
if (ldrValue < threshold) {
digitalWrite(ledPin, HIGH);
} else {
digitalWrite(ledPin, LOW);
}
delay(200);
}Check the IR sensors are close enough to the floor (roughly 0.5–1cm) and that both are wired to the correct digital pins.
Swap the left/right motor wiring — the motors may be connected in reverse of what the code expects.
Most IR modules have an onboard potentiometer — turn it slowly while watching the sensor's indicator LED to recalibrate sensitivity for your surface.
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