Photoresistor
Parts
-Arduino microcontroller and carrier board
-LiPo battery
-Photoresistor
-Jumper wires
-10kOhm resistor
Prepare the breadboard
Connect the photoresistor to GND, other leg to an A5.
Connect a resistor (around 10k is a good value, higher values gives higher readings) from pin 5 to +5V.
PhotoR 10K
GND o---/\/\/--.--/\/\/---o +5
|
Pin A5 o-----------
For a different setup:
Program the Microcontroller
/**
* @file: photoresistor example
*
* @description
* serial monitor output from photoresistor
* turns LED off when it is dark
* photoresistor, 100K resistor
*/
// include additional headers
//global declarations
#define LED 13 //define a pin for LED
#define PHOTOR 5 //define a pin for Photo resistor
const int threshold = 20; // will depend on what resistor is used
//--- Function: Setup ()
void setup()
{
pinMode(LED, OUTPUT); // setup LED
Serial.begin(9600); // setup serial output
}
//--- Function: loop ()
void loop()
{
Serial.println(analogRead(PHOTOR)); // reading values to serial monitor
if(analogRead(PHOTOR) > threshold )
{
digitalWrite(LED, HIGH); // turns on LED when it is dark
Serial.println("high");
}
else
{
digitalWrite(LED, LOW);
Serial.println("low");
}
delay(200);
}