It is not hard to use an a LED as a sensor on the Arduino. Just put a LED with the anode (positive = long leg) in analog port 0 and the cathode (negative = short leg) in GND (ground).
You can also put a LED to react on the sensor with the anode in port 13 and the cathode in GND. (you can also watch the LED already on the Arduino board).
Different colors of LEDs will have better or worse effect, so experiment with that.
Than upload the following sketch (program):
// this program is just made to experiment with a LED as a light-sensor.
int led = 13;
int basis = 0;
int sens = 0;
int x = 0;
int y = 0;
int totaal = 0;
int totaal1 = 0;
void setup() {
pinMode(led, OUTPUT);
}
void loop() { // here we do 50 readings to set the sensors
for(x =0; x < 50; x++) {
sens = analogRead(0);
totaal = totaal1 + sens; totaal1 = totaal;
}
sens = totaal/x; // divide the 50 readings by 50 again
totaal = 0;
totaal1 = 0;
basis = sens-20; // setting sensitivity - now it will react if the LED is 20 lower than the setting above
for(y=0;y<1000;y++){ // after every 1000 tests the program will reset the led to cope with changing light
for(x =0; x < 50; x++) { // 50 readings to see if the sensor is in the dark
sens = analogRead(0);
totaal = totaal1 + sens;
totaal1 = totaal;
delay(10); }
sens = totaal/x;
if (sens < basis) // testing is the led was in the dark
digitalWrite(led, HIGH); // turning the led in port 13 or on the board on if the sensor-led was 20 darker than now than in the setting
else
digitalWrite(led, LOW); // turning it of if not
totaal = 0;
totaal1 = 0;
delay(10); } }

































I see that you have several camera stands solutions. Do you have an idea for my camera problem in my other instructable?
Hoi Bertus,
Ik zag dat je aardig wat camera-statief-oplossingen hebt. Heb je niet een goed idee voor mijn camera-ondersteboven-probleem in m'n andere instructable?
http://www.instructables.com/id/camera-clamp-for-hang-glider/