MLX90614.py

# Code for MLX90614 temperature sensor
import smbus
import RPi.GPIO as GPIO
from time import sleep
class MLX90614():

	MLX90614_RAWIR1=0x04
	MLX90614_RAWIR2=0x05
	MLX90614_TA=0x06
	MLX90614_TOBJ1=0x07
	MLX90614_TOBJ2=0x08

	MLX90614_TOMAX=0x20
	MLX90614_TOMIN=0x21
	MLX90614_PWMCTRL=0x22
	MLX90614_TARANGE=0x23
	MLX90614_EMISS=0x24
	MLX90614_CONFIG=0x25
	MLX90614_ADDR=0x0E
	MLX90614_ID1=0x3C
	MLX90614_ID2=0x3D
	MLX90614_ID3=0x3E
	MLX90614_ID4=0x3F

	comm_retries = 5
	comm_sleep_amount = 0.1

	def __init__(self, address=0x5a, bus_num=1):
		self.bus_num = bus_num
		self.address = address
		self.bus = smbus.SMBus(bus=bus_num)

	def read_reg(self, reg_addr):
		err = None
		for i in range(self.comm_retries):
			try:
				return self.bus.read_word_data(self.address, reg_addr)
			except IOError as e:
				err = e
                #"Rate limiting" - sleeping to prevent problems with sensor
                #when requesting data too quickly
				sleep(self.comm_sleep_amount)
                #By this time, we made a couple requests and the sensor didn't respond
                #(judging by the fact we haven't returned from this function yet)
                #So let's just re-raise the last IOError we got
				raise err

	def data_to_temp(self, data):
		temp = (data*0.02) - 273.15
		temp += -0.7*(temp-38)
		return temp

	def get_amb_temp(self):
		data = self.read_reg(self.MLX90614_TA)
		return self.data_to_temp(data)

	def get_obj_temp(self):
		data = self.read_reg(self.MLX90614_TOBJ1)
		return self.data_to_temp(data)

if __name__ == '__main__':
	sensor = MLX90614()
	
	try:
		while(True):
			#print('temp1: ', sensor.get_amb_temp())
			print('temp2: ', sensor.get_obj_temp())
			sleep(1)
	except KeyboardInterrupt:
		print('keyboard interrupt')
#	finally:
#		GPIO.cleanup()