lightSensorTest

import spidev
import time

spi = spidev.SpiDev()
spi.open(0,0)

def readadc(adcnum):
    # read SPI data from MCP3004 chip, 4 possible adcs (0 thru 3)
    if adcnum >3 or adcnum < 0:
        return-1
    r = spi.xfer2([1,8+adcnum <<4,0])
    adcout = ((r[1] &3) <<8)+r[2]
    return adcout

while True:
    value=readadc(2)
    volts=(value*3.3)/1024
    print("%4d/1023 => %5.3f V" % (value, volts))
    time.sleep(1)