temper.py

"""
Temper - a class for managing a TEMPer USB temperature sensor

Bill Mania <bill@manialabs.us>

Source: http://www.manialabs.us/downloads/Temper.py
"""

import usb.core
import sys

class Temper():

    def __init__(self):

        self.devices = []
        self.calibrationConstant = 15
        self.units = 'C'

        self.device_list = usb.core.find(
                find_all=True,
                idVendor = 0x1130,
                idProduct = 0x660c
                )
        self.devices = [device for device in self.device_list]

        if self.devices is None:
            print 'Unable to find a temperature device'
            return

        # Try our best to detach the device from any previous state
        try:
            for device in self.devices:
                if device.is_kernel_driver_active(0):
                    device.detach_kernel_driver(0)
                if device.is_kernel_driver_active(1):
                    device.detach_kernel_driver(1)
        except NotImplementedError as e:
            #Note: some system do not implement is_kernel_driver_active
            try:
                for device in self.devices:
                    device.detach_kernel_driver(0)
                    device.detach_kernel_driver(1)
            except Exception as e:
                # I give up, maybe we will get lucky anyway
                #print "Exception: " + e.__class__.__name__ + ": " + str(e)
                pass
        except Exception as e:
            #print "Exception: " + e.__class__.__name__ + ": " + str(e)
            pass

        # Configure the device
        for device in self.devices:
            try:
                # This attach would avoid the following kernel warning, but
                # generates 2 other attach lines.  A clean "claim" would be better.
                #   kernel warning: 'process xxx (python) did not claim interface 1 before use'
                #device.attach_kernel_driver(0)
                #device.attach_kernel_driver(1)
                #device.reset()
                device.set_configuration()
            except Exception as e:
                print "Error: Unable to setup the device"
                raise e
                #print "Exception: " + e.__class__.__name__ + ": " + str(e)
                #return

        #
        # the following sequence appear to be necessary to
        # either calibrate or initialize the TEMPer, but I
        # have no idea why. therefore, I named them all "magic".
        #
        nullTrailer = ''
        for i in range(0, 24):
            nullTrailer = nullTrailer + chr(0)
        firstMagicSequence = chr(10) + chr(11) + chr(12) + chr(13)  + chr(0) + chr(0) + chr(2) + chr(0)
        firstMagicSequence = firstMagicSequence + nullTrailer
        secondMagicSequence = chr(0x54) + chr(0) + chr(0) + chr(0) + chr(0) + chr(0) + chr(0) + chr(0)
        secondMagicSequence = secondMagicSequence + nullTrailer
        thirdMagicSequence = chr(0) + chr(0) + chr(0) + chr(0) + chr(0) + chr(0) + chr(0) + chr(0)
        thirdMagicSequence = thirdMagicSequence + nullTrailer
        fourthMagicSequence = chr(10) + chr(11) + chr(12) + chr(13)  + chr(0) + chr(0) + chr(1) + chr(0)
        fourthMagicSequence = fourthMagicSequence + nullTrailer

        for device in self.devices:
            bytesSent = device.ctrl_transfer(
                0x21,
                9,
                0x200,
                0x1,
                firstMagicSequence,
                32
                )
            bytesSent = device.ctrl_transfer(
                0x21,
                9,
                0x200,
                0x1,
                secondMagicSequence,
                32
                )
            for i in range(0, 7):
                bytesSent = device.ctrl_transfer(
                    0x21,
                    9,
                    0x200,
                    0x1,
                    thirdMagicSequence,
                    32
                    )
            bytesSent = device.ctrl_transfer(
                0x21,
                9,
                0x200,
                0x1,
                fourthMagicSequence,
                32
                )

        return

    def setCalibration(self, calibrationConstant):
        self.calibrationConstant = calibrationConstant

        return

    def setUnits(self, units = 'C'):
        self.units = units

        return

    def getUnits(self):
        if self.units == 'C':
            return 'Celsius'
        elif self.units == 'F':
            return 'Fahrenheit'
        elif self.units == 'K':
            return 'Kelvin'
        else:
            return 'Unknown'

    def getTemperature(self, device):
        nullTrailer = ''
        for i in range(0, 24):
            nullTrailer = nullTrailer + chr(0)

        temperatureBuffer = device.ctrl_transfer(
            0xa1,
            1,
            0x300,
            0x1,
            256,
            0
            )

        if len(temperatureBuffer) > 1:
            if temperatureBuffer[0] == 0 and temperatureBuffer[1] == 255:
                print "Failed to retrieve temperature"
                return 0.0
            #print temperatureBuffer
            temperature = int(temperatureBuffer[0] << 8) + int(temperatureBuffer[1] & 0xff) + self.calibrationConstant
            temperature = temperature * (125.0 / 32000.0)
            if self.units == 'F':
                temperature = 9.0 / 5.0 * temperature + 32.0
            elif self.units == 'K':
                temperature = temperature + 273.15
            else:
                pass

        else:
            print "Failed to retrieve temperature"
            temperature = 0.0

        return temperature

if __name__ == '__main__':
    temper = Temper()

    for device in temper.devices:
        tempc = temper.getTemperature(device)
        tempcunits = temper.getUnits()
        tempf = (tempc * 9/5) + 32
        tempfunits = "Fahrenheit"
        devicebus = device.bus
        deviceaddress = device.address
        if len(sys.argv) < 2:
            # Example output: 0:7, 17.06 Celsius / 62.71 Fahrenheit
            print '%d:%d, %0.2f %s / %0.2f %s' % (devicebus, deviceaddress, tempc, tempcunits, tempf, tempfunits)
        else:
            if sys.argv[1] == "-c":
                # Example Celsius output: 17.06
                print '%0.2f' % tempc
            elif sys.argv[1] == "-C":
                # Example Celsius output: 17
                print '%0.0f' % tempc
            elif sys.argv[1] == "-f":
                # Example Fahrenheit output: 62.71
                print '%0.2f' % tempf
            elif sys.argv[1] == "-F":
                # Example Fahrenheit output: 62
                print '%0.0f' % tempf
            else:
                print "Usage: %s [options]" % sys.argv[0]
                print "Options:"
                print "    -c  # report Celsius"
                print "    -C  # report Celsius rounded"
                print "    -f  # report Fahrenheit"
                print "    -F  # report Fahrenheit rounded"
                print "    -h  # Help"
                sys.exit(1)