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→Simple demonstration of use
These examples assume you know some basic Arduino programming. If you don't, maybe spend some time reviewing the basics at the Arduino tutorial?
These examples assume you know some basic Arduino programming. If you don't, maybe spend some time reviewing the basics at the Arduino tutorial?
<nowiki>/* Photocell simple testing sketch.
Connect one end of the photocell to 5V, the other end to Analog 0.
Then connect one end of a 10K resistor from Analog 0 to ground
Connect LED from pin 11 through a resistor to ground
For more information see www.ladyada.net/learn/sensors/cds.html */
int photocellPin = 0; // the cell and 10K pulldown are connected to a0
int photocellReading; // the analog reading from the sensor divider
int LEDpin = 11; // connect Red LED to pin 11 (PWM pin)
int LEDbrightness; //
void setup(void) {
// We'll send debugging information via the Serial monitor
Serial.begin(9600);
}
void loop(void) {
photocellReading = analogRead(photocellPin);
Serial.print("Analog reading = ");
Serial.println(photocellReading); // the raw analog reading
// LED gets brighter the darker it is at the sensor
// that means we have to -invert- the reading from 0-1023 back to 1023-0
photocellReading = 1023 - photocellReading;
//now we have to map 0-1023 to 0-255 since thats the range analogWrite uses
LEDbrightness = map(photocellReading, 0, 1023, 0, 255);
analogWrite(LEDpin, LEDbrightness);
delay(100);
}</nowiki>
[[fichier:cds-example3.jpg]]
You may want to try different pulldown resistors depending on the light level range you want to detect!
Source: [http://www.ladyada.net/learn/sensors/cds.html cds]
Source: [http://www.ladyada.net/learn/sensors/cds.html cds]