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Software/Python/grove_i2c_multichannel_gas_sensor/multichannel_gas_sensor.py

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+#!/usr/bin/env python
+#NOTE:
+# This sensor is on port 0x04, so not compatible with grovepi unless you load an alternate firmware
+# This is work in progress, would need logic analyzer and arduino to get working
+# Error:
+#   Traceback (most recent call last):
+#  File "multichannel_gas_sensor.py", line 67, in <module>
+#    m= MutichannelGasSensor()
+#  File "multichannel_gas_sensor.py", line 21, in __init__
+#    if self.readR0() >= 0:
+#  File "multichannel_gas_sensor.py", line 27, in readR0
+#    rtnData = self.readData(0x11)
+#  File "multichannel_gas_sensor.py", line 52, in readData
+#    buffer=bus.read_i2c_block_data(self.address, cmd, 4)
+#IOError: [Errno 5] Input/output error
+#
+# LINKS
+# http://www.seeedstudio.com/wiki/Grove_-_Multichannel_Gas_Sensor
+# https://github.com/Seeed-Studio/Mutichannel_Gas_Sensor
+import time,sys
+import RPi.GPIO as GPIO
+import smbus
+
+# use the bus that matches your raspi version
+rev = GPIO.RPI_REVISION
+if rev == 2 or rev == 3:
+    bus = smbus.SMBus(1)
+else:
+    bus = smbus.SMBus(0)
+
+class MutichannelGasSensor:
+    address = None
+    is_connected = 0
+    res=[0]*3
+
+    def __init__(self,address=0x04):
+        self.address=address
+        is_connected = 0
+        if self.readR0() >= 0:
+            self.is_connected = 1
+    
+    def readR0(self):
+        rtnData = 0
+        
+        rtnData = self.readData(0x11)
+        if(rtnData >= 0):
+            self.res0[0] = rtnData
+        else:
+            return rtnData
+            
+        rtnData = self.readData(0x12)
+        if(rtnData >= 0):
+            self.res0[0] = rtnData
+        else:
+            return rtnData
+            
+        rtnData = self.readData(0x13)
+        if(rtnData >= 0):
+            self.res0[0] = rtnData
+        else:
+            return rtnData
+        return 0    
+        
+    def readData(self,cmd):
+        timeout = 0
+        buffer=[0]*4
+        checksum = 0
+        rtnData = 0
+        
+        buffer=bus.read_i2c_block_data(self.address, cmd, 4)
+        print(data)
+        
+        checksum = buffer[0] + buffer[1] + buffer[2]
+        if checksum != buffer[3]:
+            return -4
+        rtnData = ((buffer[1] << 8) + buffer[2])
+        
+        return rtnData
+   
+    def sendI2C(self,cmd):
+        bus.write_byte(self.address, cmd)
+
+
+if __name__ == "__main__":		
+	m= MutichannelGasSensor()