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
##################################################################
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