GM5539 Photocell

Product Information

http://www.aliexpress.com/store/product/Photo-Light-Sensitive-Resistor-Photoresistor-5-mm-GM5539-5539/212107_932779094.html

http://www.amazon.com/dp/B00AQVYWA2/
- Maximum Wattage: 100mW
- Operating Temperature: -30 ~ +70 deg C
- Spectral Peak: 540nm
- Light Resistance (10 Lux): 50-100 Kohm
- Dark Resistance: 5Mohm

datasheet
- http://akizukidenshi.com/download/ds/senba/GL55%20Series%20Photoresistor.pdf

Setup

because these are Light Dependent Resistors, a 10kΩ resistor is used to complete a resistive divider to read the sensors with an ADC.



In [4]:

    
!ls /dev/ttyACM*









    



/dev/ttyACM0



In [1]:

    
import time
from pyfirmata import Arduino, util
import pyfirmata
board = Arduino('/dev/ttyACM0')
it = util.Iterator(board)
it.start()
for an in board.analog:
    an.enable_reporting()
def readan(an):
    return an.read()



In [2]:

    
%%timeit
for an in board.analog:
    an.read()









    



100000 loops, best of 3: 2.6 µs per loop



In [3]:

    
%timeit map(readan, board.analog)









    



100000 loops, best of 3: 3.22 µs per loop



In [69]:

    
map(readan, board.analog)









    Out[69]:





[0.4125, 0.3656, 0.3314, 0.4194, 0.3959, 0.4066]