The Raspberry Pi works on digital signals - one or off. Analogue can be any value and normally the Raspberry Pi requires an Analogue to Digital converter.
I have one connected to a 2m length of cable and one connected to a 20cm length of cable.
Requires a 1uf Capacitor
Resource - http://learn.adafruit.com/basic-resistor-sensor-reading-on-raspberry-pi
Takes a parameter of RCpin. This is the pin where the resistor is connected to. I have 2 connected to the system, one inside, one out. The inside sensor is basically dark all day.
################################################################### def RCtime(RCpin): reading = 0 GPIO.setup(RCpin, GPIO.OUT) GPIO.output(RCpin, GPIO.LOW) time.sleep(0.1) GPIO.setup(RCpin, GPIO.IN) # This takes about 1 millisecond per loop cycle while (GPIO.input(RCpin) == GPIO.LOW): reading += 1 if reading > 200: break return reading def pdslight(GPIOPIN): if debug: print("Reading light " + str(GPIOPIN)) x=0 loops=5 for y in range(0,loops): x = x + RCtime(GPIOPIN) x = x/loops if debug: print("Reading light " + str(GPIOPIN) + " " + str(x) ) return x ##################################################################