Arduino 各种模块篇 光敏感应模块 light sensor

It looks like this one:

This one isn't a digital light sensor, so it's very simple.

http://www.seeedstudio.com/wiki/Grove_-_Light_Sensor

With seeeduino and it's grove shield, this would be very easy to use.

Now we can do a little experiment:

using a LED and a light sensor.

condition 1) If the sensor detects light, the LED will no longer be on. 2) If the sensor detects no light, the LED will be on.

Here is the codes and demo.

codes:

/*
/* Grove - Light Sensor demo v1.0
* 
* signal wire to A0.
* By: http://www.seeedstudio.com
*/
#include <math.h>
const int ledPin=12;                 //Connect the LED Grove module to Pin12, Digital 12
const int thresholdvalue=10;         //The treshold for which the LED should turn on. 
float Rsensor; //Resistance of sensor in K
void setup() {
  Serial.begin(9600);                //Start the Serial connection
  pinMode(ledPin,OUTPUT);            //Set the LED on Digital 12 as an OUTPUT
}
void loop() {
  int sensorValue = analogRead(0); 
  Rsensor=(float)(1023-sensorValue)*10/sensorValue;  // using the sensor's analog voltage to caculate the accurate resistance value of it.
  if(Rsensor>thresholdvalue)              // thresholdvalue = 10 which means if the Rsensor is more than 10K oms (ligth sensor been covered)
  {
    digitalWrite(ledPin,HIGH);            // light sensor covered ==> light on the LED
  }
  else                                    // light sensor detects light
  {
  digitalWrite(ledPin,LOW);               // light off the LED
  }
  Serial.println("the analog read data is ");
  Serial.println(sensorValue);
  Serial.println("the sensor resistance is ");
  Serial.println(Rsensor,DEC);//show the ligth intensity on the serial monitor;
  delay(1000);
}