Hi everyone. I'm trying to read my Seed Grove Multichannel gas sensor. (http://wiki.seeed.cc/Grove-Multichannel_Gas_Sensor/) I now, in the webpage the're a red X on Beaglebone, but I thought It was due to lack of python library.
So I started coding from the Arduino cpp library (that works): https://github.com/Seeed-Studio/Mutichannel_Gas_Sensor/blob/master/MutichannelGasSensor.cpp If I plug the groove, I see it with i2cdetect -r 2: root@beaglebone:~# i2cdetect -r 2 WARNING! This program can confuse your I2C bus, cause data loss and worse! I will probe file /dev/i2c-2 using read byte commands. I will probe address range 0x03-0x77. Continue? [Y/n] 0 1 2 3 4 5 6 7 8 9 a b c d e f 00: -- 04 -- -- -- -- -- -- -- -- -- -- -- 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 50: -- -- -- -- UU UU UU UU -- -- -- -- -- -- -- -- 60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 70: -- -- -- -- -- -- -- -- At the moment I'm using Adafruit_I2C library to write/read. This is my Class: class MutichannelGasSensor: address = None def __init__(self, mode=1, address=0x04, i2c=None, **kwargs): i2c = Adafruit_I2C(0x04, busnum=2, debug=True) self._device = i2c self.address=0x04 self.adcValueR0_NH3_Buf = 0; self.adcValueR0_CO_Buf = 0; self.adcValueR0_NO2_Buf = 0; #POWER ON dta_test = [11,1] self._device.writeList(self.address, dta_test) self.calcGas() def calcGas(self): # how to calc ratio/123 #ledON dta_test = [10, 1] self._device.writeList(self.address, dta_test) time.sleep(1) A0_0 = self.get_addr_dta(6, 8) time.sleep(1) A0_1 = self.get_addr_dta(6, 10) time.sleep(1) A0_2 = self.get_addr_dta(6, 12) print "A0_0: " + str(A0_0) print "A0_1: " + str(A0_1) print "A0_2: " + str(A0_2) def get_addr_dta(self, addr_reg, __dta): self._device.write8(0x04, addr_reg) self._device.write8(0x04, __dta) testArray = self._device.readList(self.address, 2) dta=0 dta = testArray[0] dta <<= 8 dta += testArray[1] if addr_reg == 8: #CH_VALUE_NH3 self.adcValueR0_NH3_Buf = dta; elif addr_reg == 10: #CH_VALUE_CO self.adcValueR0_CO_Buf = dta; elif addr_reg == 12: #CH_VALUE_NO2 self.adcValueR0_NO2_Buf = dta; return dta The problem is when I call calcGas() and get_addr_dta(6, 8) , get_addr_dta(6, 10) and get_addr_dta(6, 12): I wrote in three different registers, but I read always the same value from it (A0_0, A0_1 and A0_2) while they're differente on an Arduino. Why? The same function in Arduino is: unsigned int MutichannelGasSensor::get_addr_dta(unsigned char addr_reg, unsigned char __dta){ START: Wire.beginTransmission(i2cAddress); Wire.write(addr_reg); Wire.write(__dta); Wire.endTransmission(); // stop transmitting Wire.requestFrom(i2cAddress, 2); unsigned int dta = 0; unsigned char raw[10]; int cnt = 0; while(Wire.available()) { raw[cnt++] = Wire.read(); } if(cnt == 0)goto START; dta = raw[0]; dta <<= 8; dta += raw[1]; return dta; } The sensor datasheet is useless: https://raw.githubusercontent.com/SeeedDocument/Grove-Multichannel_Gas_Sensor/master/res/MiCS-6814_Datasheet.pdf Thank you for the support :) -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/97e1cd24-8f52-472f-9603-f26f295511f1%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
