requestforcoffee/scd30

Python I2C driver for the SCD30 CO2, temperature and humidity sensor.

scd30's Issues

Missing files

I'm might be missing something in the setup but when running the sample I get the following error:

FileNotFoundError: [Errno 2] No such file or directory: '/dev/i2c-1'.

Any idea what it could be?

One question..

Can I compensate co2 measurements with data from external pressure sensor like BMP280?
How?
Thanks

Temperature compensation fails

The temperature compensation fails to write to the register and always stays the same

Configure Python requirements.txt

smbus2 and other dependencies should be added to requirements.txt and installed together with the package.

Sample code doesn’t work

Hi,

I’m quite new to the scene and I can’t manage to make the sample code work on my raspi 4B.
I’ve followed the instructions, installed the scd30_i2c package, did the wiring and copied the sample code to Thonny IDE on my raspi that I access trough VNC. When runing the code I get the following error msgs:

"
Traceback (most recent call last):
File "/home/pita/Documents/Malina SCD30 test.py", line 5, in
scd30 = SCD30()
File "/home/pita/.local/lib/python3.7/site-packages/scd30_i2c/init.py", line 17, in init
self._i2c = smbus2.SMBus(1)
File "/home/pita/.local/lib/python3.7/site-packages/smbus2/smbus2.py", line 279, in init
self.open(bus)
File "/home/pita/.local/lib/python3.7/site-packages/smbus2/smbus2.py", line 308, in open
self.fd = os.open(filepath, os.O_RDWR)
PermissionError: [Errno 13] Permission denied: '/dev/i2c-1'
"

I think this is because I did not do something in the "Software configuration and I²C clock stretching" part of the tutorial. This is because this part is clarifying why i2c clock stretching is required but it doesn’t give precise instructions on how to achieve the software configuration and I2C clock stretching.

Please advise what do I need to do in this part of the tutorial.

Thank you, cheers!

Bug in project description on pypi.org

Hi, the sample code on pypi is missing the "import time".

https://pypi.org/project/scd30-i2c/

Memory Leak calling #get_data_ready

Calling sensor.get_data_ready() in a loop causes a slow memory leak. It gets worse if periodic measurement is enabled.

import time
import tracemalloc

from scd30_i2c import SCD30

def print_trace_diff(a, b):
    stats = [s for s in b.compare_to(a, 'lineno') if not s.traceback[0].filename.endswith('tracemalloc.py')]
    stats = [s for s in stats if s.size_diff != 0]                                                                                                                                                                                                                                                                                                                                                      

    if stats:
        for stat in stats[:10]:
            print(stat)                                                                                                                                                                                                                                                                                                                       


def main():
    tracemalloc.start(10)
    snap = tracemalloc.take_snapshot()

    scd30 = SCD30()

    #scd30.set_measurement_interval(5)                                                                                                                                                                                                                                                                                                                                                                                                  
    #scd30.start_periodic_measurement()                                                                                                                                                                                                                                                                                                                                                                                                 
    try:
        while True:
            print("ready: ", scd30.get_data_ready())
            time.sleep(5)
            print_trace_diff(snap, tracemalloc.take_snapshot())
            print()
    except KeyboardInterrupt:
#        scd30.stop_periodic_measurement()                                                                                                                                                                                                                                                                                                                                                                                              
        scd30.soft_reset()


if __name__ == '__main__':
    main()

The first print looks something like:

ready:  0
/usr/lib/python3.7/ctypes/__init__.py:60: size=1332 B (+1332 B), count=20 (+20), average=67 B
/usr/lib/python3.7/ctypes/__init__.py:55: size=1288 B (+1288 B), count=19 (+19), average=68 B
/home/dave/project/lib/python3.7/site-packages/smbus2/smbus2.py:252: size=1242 B (+1242 B), count=17 (+17), average=73 B
/usr/lib/python3.7/enum.py:892: size=936 B (+936 B), count=26 (+26), average=36 B
/home/dave/project/lib/python3.7/site-packages/scd30_i2c/__init__.py:174: size=780 B (+780 B), count=2 (+2), average=390 B
/home/dave/project/lib/python3.7/site-packages/scd30_i2c/__init__.py:136: size=720 B (+720 B), count=3 (+3), average=240 B
/usr/lib/python3.7/logging/__init__.py:2003: size=404 B (+404 B), count=1 (+1), average=404 B
/home/dave/project/lib/python3.7/site-packages/scd30_i2c/__init__.py:153: size=372 B (+372 B), count=1 (+1), average=372 B
/home/dave/project/lib/python3.7/site-packages/scd30_i2c/__init__.py:131: size=364 B (+364 B), count=1 (+1), average=364 B
/home/dave/project/lib/python3.7/site-packages/scd30_i2c/__init__.py:121: size=364 B (+364 B), count=1 (+1), average=364 B

By the time its run a few times, you can see a steady increase in the number of objects allocated by the library:

/usr/lib/python3.7/ctypes/__init__.py:60: size=1484 B (+1484 B), count=23 (+23), average=65 B
/usr/lib/python3.7/ctypes/__init__.py:55: size=1440 B (+1440 B), count=22 (+22), average=65 B
/home/dave/project/lib/python3.7/site-packages/smbus2/smbus2.py:252: size=1394 B (+1394 B), count=20 (+20), average=70 B
/usr/lib/python3.7/enum.py:892: size=936 B (+936 B), count=26 (+26), average=36 B
############## Steady, monotonic increase on line 136 below 
/home/dave/project/lib/python3.7/site-packages/scd30_i2c/__init__.py:136: size=864 B (+864 B), count=7 (+7), average=123 B
/home/dave/project/lib/python3.7/site-packages/scd30_i2c/__init__.py:174: size=780 B (+780 B), count=2 (+2), average=390 B
/usr/lib/python3.7/logging/__init__.py:2003: size=404 B (+404 B), count=1 (+1), average=404 B
/home/dave/project/lib/python3.7/site-packages/scd30_i2c/__init__.py:153: size=372 B (+372 B), count=1 (+1), average=372 B=

Documentation missing: Which Raspberry Pi's are supported?

Hi,
could you provide a list of RPi's that are known to work with the library?
If there are special tweaks necessary for other than RPi4, that would also be helpful.
Yours
S