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#!/usr/bin/python
# Code sourced from AdaFruit discussion board: https://www.adafruit.com/forums/viewtopic.php?f=8&t=34922
import sys
# Not needed here. Thanks to https://github.com/mackstann for highlighting this.
#import smbus
import time
#Adafruit_I2C from https://github.com/adafruit/Adafruit-Raspberry-Pi-Python-Code/blob/master/Adafruit_I2C/Adafruit_I2C.py
from Adafruit_I2C import Adafruit_I2C
### Written for Python 2 <-!!!
### Big thanks to bryand, who wrote the code that I borrowed heavily from/was inspired by
### More thanks pandring who kind of kickstarted my work on the TSL2561 sensor
### A great big huge thanks to driverblock and the Adafruit team (Congrats on your many succeses
### Ladyada). Without you folks I would just be a guy sitting somewhere thinking about cool stuff
### Now I'm a guy building cool stuff.
### If any of this code proves useful, drop me a line at medicforlife.blogspot.com
# TODO: Strip out values into constants.
class TSL2561:
i2c = None
def __init__(self, address=0x39, debug=0, pause=0.8):
self.i2c = Adafruit_I2C(address)
self.address = address
self.pause = pause
self.debug = debug
self.gain = 0 # no gain preselected
self.i2c.write8(0x80, 0x03) # enable the device
def setGain(self,gain=1):
""" Set the gain """
if (gain != self.gain):
if (gain==1):
self.i2c.write8(0x81, 0x02) # set gain = 1X and timing = 402 mSec
if (self.debug):
print "Setting low gain"
else:
self.i2c.write8(0x81, 0x12) # set gain = 16X and timing = 402 mSec
if (self.debug):
print "Setting high gain"
self.gain=gain; # safe gain for calculation
time.sleep(self.pause) # pause for integration (self.pause must be bigger than integration time)
def readWord(self, reg):
"""Reads a word from the I2C device"""
try:
wordval = self.i2c.readU16(reg)
newval = self.i2c.reverseByteOrder(wordval)
if (self.debug):
print("I2C: Device 0x%02X returned 0x%04X from reg 0x%02X" % (self.address, wordval & 0xFFFF, reg))
return newval
except IOError:
print("Error accessing 0x%02X: Check your I2C address" % self.address)
return -1
def readFull(self, reg=0x8C):
"""Reads visible+IR diode from the I2C device"""
return self.readWord(reg);
def readIR(self, reg=0x8E):
"""Reads IR only diode from the I2C device"""
return self.readWord(reg);
def readLux(self, gain = 0):
"""Grabs a lux reading either with autoranging (gain=0) or with a specified gain (1, 16)"""
if (gain == 1 or gain == 16):
self.setGain(gain) # low/highGain
ambient = self.readFull()
IR = self.readIR()
elif (gain==0): # auto gain
self.setGain(16) # first try highGain
ambient = self.readFull()
if (ambient < 65535):
IR = self.readIR()
if (ambient >= 65535 or IR >= 65535): # value(s) exeed(s) datarange
self.setGain(1) # set lowGain
ambient = self.readFull()
IR = self.readIR()
if (self.gain==1):
ambient *= 16 # scale 1x to 16x
IR *= 16 # scale 1x to 16x
ratio = (IR / float(ambient)) # changed to make it run under python 2
if (self.debug):
print "IR Result", IR
print "Ambient Result", ambient
if ((ratio >= 0) & (ratio <= 0.52)):
lux = (0.0315 * ambient) - (0.0593 * ambient * (ratio**1.4))
elif (ratio <= 0.65):
lux = (0.0229 * ambient) - (0.0291 * IR)
elif (ratio <= 0.80):
lux = (0.0157 * ambient) - (0.018 * IR)
elif (ratio <= 1.3):
lux = (0.00338 * ambient) - (0.0026 * IR)
elif (ratio > 1.3):
lux = 0
return lux
if __name__ == "__main__":
tsl=TSL2561()
print tsl.readLux()
#print "LUX HIGH GAIN ", tsl.readLux(16)
#print "LUX LOW GAIN ", tsl.readLux(1)
#print "LUX AUTO GAIN ", tsl.readLux()