I’m trying to write a python script to use my and it WON’T respond. I’m sure my python code is good, but I keep getting this horrible error. It’s like the ccs811 isn’t even attached! I mean, look at this:
Traceback (most recent call last): File "weather.py", line 54, in print(str(ccs811.tvoc)) File "/usr/local/lib/python3.7/dist-packages/adafruit_ccs811.py", line 162, in tvoc self._update_data() File "/usr/local/lib/python3.7/dist-packages/adafruit_ccs811.py", line 147, in _update_data if self.data_ready: File "/usr/local/lib/python3.7/dist-packages/adafruit_register/i2c_bit.py", line 60, in <strong>get</strong> i2c.write_then_readinto(self.buffer, self.buffer, out_end=1, in_start=1) File "/usr/local/lib/python3.7/dist-packages/adafruit_bus_device/i2c_device.py", line 156, in write_then_readinto in_end=in_end, File "/usr/local/lib/python3.7/dist-packages/busio.py", line 118, in writeto_then_readfrom stop=stop, File "/usr/local/lib/python3.7/dist-packages/adafruit_blinka/microcontroller/generic_linux/i2c.py", line 85, in writeto_then_readfrom address, buffer_out[out_start:out_end], in_end - in_start File "/usr/local/lib/python3.7/dist-packages/Adafruit_PureIO/smbus.py", line 273, in read_i2c_block_data ioctl(self._device.fileno(), I2C_RDWR, request) OSError: [Errno 121] Remote I/O error
What the hell?!?!
I do a little research and realize that the module has issues when it runs at full speed. The trick to getting the Adafruit Gas Sensor to respond is to slow down the i2c bus speed. This is simple to do.
Edit /boot/config.txt and add a couple of lines to the end:
core_freq=500 core_freq_min=500 dtparm=i2c_arm=on,i2c_arm_baudrate=10000
Reboot and run your script again! After a couple of minutes, the heater comes to operating temp and you start getting good readings! w00t!
I’m working on getting this Adafruit Gas Sensor installed above my 3D printer to watch for high fume levels coming from the printing process.