bh1750.py

#!/usr/bin/env python
# encoding: utf-8
 
import smbus
import time
 
#BH1750地址
__DEV_ADDR=0x23
 
#控制字
__CMD_PWR_OFF=0x00  #关机
__CMD_PWR_ON=0x01   #开机
__CMD_RESET=0x07    #重置
__CMD_CHRES=0x10    #持续高分辨率检测
__CMD_CHRES2=0x11   #持续高分辨率模式2检测
__CMD_CLHRES=0x13   #持续低分辨率检测
__CMD_THRES=0x20    #一次高分辨率
__CMD_THRES2=0x21   #一次高分辨率模式2
__CMD_TLRES=0x23    #一次分辨率
__CMD_SEN100H=0x42  #灵敏度100%,高位
__CMD_SEN100L=0X65  #灵敏度100%，低位
__CMD_SEN50H=0x44   #50%
__CMD_SEN50L=0x6A   #50%
__CMD_SEN200H=0x41  #200%
__CMD_SEN200L=0x73  #200%
 
bus=smbus.SMBus(1)
bus.write_byte(__DEV_ADDR,__CMD_PWR_ON)
bus.write_byte(__DEV_ADDR,__CMD_RESET)
bus.write_byte(__DEV_ADDR,__CMD_SEN100H)
bus.write_byte(__DEV_ADDR,__CMD_SEN100L)
bus.write_byte(__DEV_ADDR,__CMD_PWR_OFF)
def getIlluminance():
	bus.write_byte(__DEV_ADDR,__CMD_PWR_ON)
	bus.write_byte(__DEV_ADDR,__CMD_THRES2)
	time.sleep(0.2)
	res=bus.read_word_data(__DEV_ADDR,0)
	#read_word_data
	res=((res>>8)&0xff)|(res<<8)&0xff00
	res=round(res/(2*1.2),2)
	#result="光照强度: "+str(res)+"lx"
	#return result
	return res
if __name__ == '__main__':
    while(True):
		try:
			print "光照强度: " + str(getIlluminance()) + "lx"
		except KeyboardInterrupt:
			exit()