t6713.py

#
#  Code can be found at @ https://www.raspberrypi.org/forums/viewtopic.php?f=32&t=153764
#  By user: edwardsnick
#  Use at your own risk!
# 
#  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING 
#  BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 
#  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 
#  DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 
#  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
#
#!/usr/bin/python

import math, struct, array, time, io, fcntl

bus = 1
addressT6713 = 0x15
I2C_SLAVE=0x0703

class i2c(object):
	def __init__(self, device, bus):

		self.fr = io.open("/dev/i2c-"+str(bus), "rb", buffering=0)
		self.fw = io.open("/dev/i2c-"+str(bus), "wb", buffering=0)

		# set device address

		fcntl.ioctl(self.fr, I2C_SLAVE, device)
		fcntl.ioctl(self.fw, I2C_SLAVE, device)

	def write(self, bytes):
		self.fw.write(bytes)

	def read(self, bytes):
		return self.fr.read(bytes)

	def close(self):
		self.fw.close()
		self.fr.close()

class T6713(object):
	def __init__(self):
		self.dev = i2c(addressT6713, bus)

	def status(self):
		buffer = array.array('B', [0x04, 0x13, 0x8a, 0x00, 0x01])
		self.dev.write(buffer)
		time.sleep(0.1)
		data = self.dev.read(4)
		buffer = array.array('B', data)
		return buffer[2]*256+buffer[3]

	def gasPPM(self):
		buffer = array.array('B', [0x04, 0x13, 0x8b, 0x00, 0x01])
		self.dev.write(buffer)
		time.sleep(0.1)
		data = self.dev.read(4)
		buffer = array.array('B', data)
		return buffer[2]*256+buffer[3]

	def checkABC(self):
		buffer = array.array('B', [0x04, 0x03, 0xee, 0x00, 0x01])
		self.dev.write(buffer)
		time.sleep(0.1)
		data = self.dev.read(4)
		buffer = array.array('B', data)
		return buffer[2]*256+buffer[3]

	def calibrate(self):
		buffer = array.array('B', [0x05, 0x03, 0xec, 0xff, 0x00])
		self.dev.write(buffer)
		time.sleep(0.1)
		data = self.dev.read(5)
		buffer = array.array('B', data)
		return buffer[3]*256+buffer[3]

if __name__ == "__main__":
	obj = T6713()
	print "Status: ", bin(obj.status())
	print "PPM: ", obj.gasPPM()
	print "ABC State: ", obj.checkABC()