Arduino LDR LED dimmer.cpp

#define SENSORPIN 0
#define PWMPIN 3

int sensorMax = -1;
int sensorMin = 1024;

void setup() { }

void loop() {
  delay(10);
  analogWrite(PWMPIN,readLDRValue());
}

/* 
 * Returns the value of the LDR on the scale of 0-255
 * Needs defined: 
 *  * SENSORPIN (pin onto which LDR is connected)
 *  * PWMPIN (PWM pin onto which the LED/output is connected)
 * 
*/
int readLDRValue() {
  int sensorValue = 0;  // variable to store the value coming from the sensor

   sensorValue = map(analogRead(SENSORPIN),0,1023,0,255);
  
  if (sensorValue > sensorMax)
    sensorMax = sensorValue;  
  if (sensorValue < sensorMin)
   sensorMin = sensorValue;
  return sensorValue;
}

Hi Lisa,
Just want to check if the lines should not have the value assignment swapped around?:
if (sensorValue > sensorMax)
sensorValue = sensorMax;
if (sensorValue < sensorMin)
sensorValue = sensorMin;