mh_z19
Read CO2 concentration from mh-z19 sensor
pip install mh-z19
Use as python script.
pi@raspberrypi:~/mh-z19/pypi $ sudo python -m mh_z19
{'co2': 500}
Import module and call read()
pi@raspberrypi:~/mh-z19/pypi $ sudo python
Python 2.7.13 (default, Nov 24 2017, 17:33:09)
[GCC 6.3.0 20170516] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import mh_z19
>>> mh_z19.read()
{'co2': 477}
>>>
The sudo might be necessary because mh_z19 module use Serial.
The differences of the interface between each Raspberry Pi modle are resolved inside this module. For example, serial device name is difference between Raspberry Pi 3 and older model, but mh-z19 module automatically detect the model and read from appropriate serial device.
To use mh-z19, once you need to set up enabling serial port device on the Raspbyerr Pi. Following Wiki page might be informative.
Connect RPi & mh-z19 as:
- 5V on RPi and Vin on mh-z19
- GND(0v) on RPi and GND on mh-z19
- TxD and RxD are connect to cross between RPi and mh-z18
Followings are example of cabling, but you can free to use other 5v and 0v Pin on the RPi.
pi@raspberrypi:~/mh-z19 $ gpio readall
+-----+-----+---------+------+---+---Pi B+--+---+------+---------+-----+-----+
| BCM | wPi | Name | Mode | V | Physical | V | Mode | Name | wPi | BCM |
+-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
| | | 3.3v | | | 1 || 2 | | | 5v | | |
| 2 | 8 | SDA.1 | IN | 1 | 3 || 4 | | | 5v | | | <---- Vin
| 3 | 9 | SCL.1 | IN | 1 | 5 || 6 | | | 0v | | | <---- Gnd
| 4 | 7 | GPIO. 7 | IN | 1 | 7 || 8 | 1 | ALT0 | TxD | 15 | 14 | <---- RxD
| | | 0v | | | 9 || 10 | 1 | ALT0 | RxD | 16 | 15 | <---- TxD
| 17 | 0 | GPIO. 0 | IN | 0 | 11 || 12 | 0 | IN | GPIO. 1 | 1 | 18 |
| 27 | 2 | GPIO. 2 | IN | 0 | 13 || 14 | | | 0v | | |
| 22 | 3 | GPIO. 3 | IN | 0 | 15 || 16 | 0 | IN | GPIO. 4 | 4 | 23 |
| | | 3.3v | | | 17 || 18 | 0 | IN | GPIO. 5 | 5 | 24 |
| 10 | 12 | MOSI | IN | 0 | 19 || 20 | | | 0v | | |
| 9 | 13 | MISO | IN | 0 | 21 || 22 | 0 | IN | GPIO. 6 | 6 | 25 |
| 11 | 14 | SCLK | IN | 0 | 23 || 24 | 1 | IN | CE0 | 10 | 8 |
| | | 0v | | | 25 || 26 | 1 | IN | CE1 | 11 | 7 |
| 0 | 30 | SDA.0 | IN | 1 | 27 || 28 | 1 | IN | SCL.0 | 31 | 1 |
| 5 | 21 | GPIO.21 | IN | 1 | 29 || 30 | | | 0v | | |
| 6 | 22 | GPIO.22 | IN | 1 | 31 || 32 | 0 | IN | GPIO.26 | 26 | 12 |
| 13 | 23 | GPIO.23 | IN | 0 | 33 || 34 | | | 0v | | |
| 19 | 24 | GPIO.24 | IN | 0 | 35 || 36 | 0 | IN | GPIO.27 | 27 | 16 |
| 26 | 25 | GPIO.25 | IN | 0 | 37 || 38 | 0 | IN | GPIO.28 | 28 | 20 |
| | | 0v | | | 39 || 40 | 0 | IN | GPIO.29 | 29 | 21 |
+-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
| BCM | wPi | Name | Mode | V | Physical | V | Mode | Name | wPi | BCM |
+-----+-----+---------+------+---+---Pi B+--+---+------+---------+-----+-----+
Any questions, suggestions, reports are welcome! Please make issue without hesitation!
- 0.1.1 2018.11.05 first version self-forked from slider.
- 0.1.3 2018.11.06 fix Readme.
- 0.1.4 2018.11.15 revise Readme.