Help with MH-Z19 sensor (serial0 issues)

Hi all,
I have been following the guide here: https://home-assistant.io/components/sensor.mhz19/ trying to setup the sensor but it does not seem to work, the sensor does not show up.
I thought it might be because of UART was not setup so I followed this guide: http://www.circuits.dk/setup-raspberry-pi-3-gpio-uart/ by using the ls -l /dev command I can identify the serial port but run the test script I get this error: File “/usr/lib/python2.7/dist-packages/serial/serialutil.py”, line 261, in init
self.open()
File “/usr/lib/python2.7/dist-packages/serial/serialposix.py”, line 278, in open
raise SerialException(“could not open port %s: %s” % (self._port, msg))
serial.serialutil.SerialException: could not open port serial0: [Errno 2] No such file or directory: ‘serial0’
Any idea what I am doing wrong?
BR,
Lars
PS I am running Hassbian

Do you solved the problem?
I have the same here :frowning: