scd30

Python library for the Sensirion SCD30 co2, temperature, humidity sensor.

I2C Clock stretching

Master needs to support Clock Stretching up to 150ms. The default in Raspbian is too low, we have to increase it:

To set it, download from here:

https://github.com/raspihats/raspihats/tree/master/clk_stretch

Compile:

gcc -o i2c1_set_clkt_tout i2c1_set_clkt_tout.c
gcc -o i2c1_get_clkt_tout i2c1_get_clkt_tout.c

execute (add to /etc/rc.local to run on every boot):

./i2c1_set_clkt_tout 20000 # for 200ms

Thanks

I borrowed some code and ideas from these two repos:

https://github.com/UnravelTEC/Raspi-Driver-SCD30 (python code, i2c clock stretching) https://github.com/sparkfun/SparkFun_SCD30_Arduino_Library (code structure, commands)