Reef-Pi CO2 Monitoring

[atlantean]

Finished writing the code to integrate ambient CO2 monitoring using the SCD41 sensor through the I2C port on my Robotank. I leveraged this guidance and then just modified it to reflect the SCD41 sensor: https://www.reef2reef.com/threads/sht20-temperature-humidity-with-reef-pi.817553/

I'm still working on some interference issues that popped up, but I think its related to a setting I changed when I was problem-solving the i2c connectivity and forgot to change back.

Thought I'd post the script in case its helpful for anyone else:

import os
import time
import board
import busio
import adafruit_scd4x

i2c_address = 0x62
i2c_bus = busio.I2C(board.SCL, board.SDA)
rootDir = "/dev/shm"
WorkDrir = "/ReeFHardwareComs/SCD41"
path = rootDir + WorkDrir
access_rights = 0o755

F_Hum_Name = "SCD41_Hum"
F_Temp_name = "SCD41_Temp"
F_CO2_name = "SCD41_CO2"

if not os.path.isdir(path):
try:
os.makedirs(path, access_rights)
except OSError:
print("Creation of the directory %s failed" % path)
else:
print("Successfully created the directory %s " % path)

scd4x = adafruit_scd4x.SCD4X(i2c_bus, i2c_address)
print("Serial number:", [hex(i) for i in scd4x.serial_number])

scd4x.start_periodic_measurement()
print("Waiting for first measurement....")

while True:
if scd4x.data_ready:
co2 = scd4x.CO2
temperature_c = scd4x.temperature
temperature_f = temperature_c * 9 / 5 + 32
humidity = scd4x.relative_humidity

print("CO2: %d ppm" % co2)
print("Temperature: %0.1f °F" % temperature_f)
print("Humidity: %0.1f %%" % humidity)
print()

F_CO2 = open(path + "/" + F_CO2_name, "w")
strSHT = repr(co2)
F_CO2.write(strSHT)
F_CO2.close()
os.chmod(path + "/" + F_CO2_name, access_rights)

F_Temp = open(path + "/" + F_Temp_name, "w")
strSHT = repr(temperature_f)
F_Temp.write(strSHT)
F_Temp.close()
os.chmod(path + "/" + F_Temp_name, access_rights)

F_Hum = open(path + "/" + F_Hum_Name, "w")
strSHT = repr(humidity)
F_Hum.write(strSHT)
F_Hum.close()
os.chmod(path + "/" + F_Hum_Name, access_rights)

time.sleep(1)

 

[Sral]

Nice work !

Would be interesting to see if the command set is identical/similar to the SCD-30 program I wrote some time ago.

 

[Devin_Tesla]

Nice with my ph probe problems how I'm currently controlling co2 I may just try this

 

[Sral]

Nice with my ph probe problems how I'm currently controlling co2 I may just try this

I’m not quite sure, if I understand your goals here. The sensor here measures CO2 in the ambient air, not the one in the water.

If you want to control ph that way, you might be better off using a CO2 scrubber in your skimmer‘s air intake or feed it ambient air with a lower CO2 content than the one in your cupboard.

 

[Ranjib]

Very nice ;-)