49 lines
2.4 KiB
ReStructuredText
49 lines
2.4 KiB
ReStructuredText
RPI_SGP30
|
|
=========
|
|
|
|
Library to read |eCO_2| and TVOC from the `SGP30 sensor <https://www.sensirion.com/fileadmin/user_upload/customers/sensirion/Dokumente/9_Gas_Sensors/Sensirion_Gas_Sensors_SGP30_Datasheet_EN.pdf>`_. Based on the smbus2 i2c library for ease of use.
|
|
|
|
|
|
Quick usage-example:
|
|
--------------------
|
|
::
|
|
|
|
from smbus2 import SMBusWrapper
|
|
from sgp30 import Sgp30
|
|
import time
|
|
with SMBusWrapper(1) as bus:
|
|
sgp=Sgp30(bus,baseline_filename="/tmp/mySGP30_baseline") #things thing with the baselinefile is dumb and will be changed in the future
|
|
print("resetting all i2c devices")
|
|
sgp.i2c_geral_call() #WARNING: Will reset any device on teh i2cbus that listens for general call
|
|
print(sgp.read_features())
|
|
print(sgp.read_serial())
|
|
sgp.init_sgp()
|
|
print(sgp.read_measurements())
|
|
print("the SGP30 takes at least 15 seconds to warm up, 12 hours before the readigs become really stable"
|
|
for i in range(20):
|
|
time.sleep(1)
|
|
print(".",end="")
|
|
print()
|
|
print(sgp.read_measurements())
|
|
|
|
Current design considerations:
|
|
-------------------------------
|
|
The class strives to to be light-weight and portable. It is currently a bit to tightly bound to the smbus2 class. In most cases I try to ease of readability rather than purity or speed.
|
|
|
|
Features that are known to be missing (listing in rough order of importance):
|
|
-----------------------------------------------------------------------------
|
|
* Fix python3 compatibility.
|
|
* The handing of baseline values is not that great, it should probably be up to the end user to save and restore them as needed.
|
|
* Write doc-strings for all or at least most methods.
|
|
* reading raw-values.
|
|
* A more "driver like" class that takes care of all chip identification, polling at regular intervals, restoring baseline and so on.
|
|
|
|
Hardware notices:
|
|
-----------------
|
|
If you have the Adafruit board with built in level shifters and voltage regulator it is should work if you just plug in `SDA to pin 3, SCL to pin 5, VCC to pin 17 and GND to pin 20 <https://pinout.xyz/pinout/i2c>`_. You should then be able to find the SGP30 an address 0x58 using `i2cdetect -y 1`. If you get an error message you probably need to enable i2c in the kernel using `raspi-config and reboot <https://learn.sparkfun.com/tutorials/raspberry-pi-spi-and-i2c-tutorial>`_
|
|
|
|
|
|
Feel free to contact me with bugs, questions or issues.
|
|
|
|
.. |eCO_2| replace:: eCO\ :sub:`2`
|