Software for CO2 Monitor

Based on https://github.com/dmage/co2mon, go implementation https://github.com/kdudkov/co2mon, python script https://gist.github.com/librarian/306e06c51fe5f53ded6ebc761580b62b and article https://hackaday.io/project/5301-reverse-engineering-a-low-cost-usb-co-monitor

This fork tested to work with KIT MT8057S.

How to use

Permissions to access device

Create udev rule in file /etc/udev/rules.d/50-local-raw-usb.rules like this:

SUBSYSTEM=="usb", ATTRS{idVendor}=="04d9", ATTRS{idProduct}=="a052",  MODE="0666"
SUBSYSTEM=="hidraw", ATTRS{idVendor}=="04d9", ATTRS{idProduct}=="a052", MODE="0666"

and restart udev:

$ sudo udevadm control --reload-rules && sudo udevadm trigger

This allows you to use the device without root permissions.

Create local user

adduser co2mon

Create Service Account with proper permissions

yc init
yc resource-manager folder create co2mon --cloud-id b1gXXXXXXX
yc iam service-account create co2mon --folder-id b1gXXXXXXX
yc resource-manager folder add-access-binding --id b1gXXXXXXX  --service-account-id ajeXXXXXXX --role monitoring.editor
yc iam key create --service-account-id ajeXXXXXXX  --format json --output sa_key_2024.json

Move sa_key_2024.json into /home/co2mon, chmod to allow read by co2mon user.

Binaries and systemd units

Place binaries co2mon and ycpusher into /usr/local/bin directory.

Create two systemd units and start them.

file /etc/systemd/system/co2mon.service:

[Unit]
Description=co2mon Service
After=network.target

[Service]
ExecStart=/usr/local/bin/co2mon
Restart=always
User=co2mon
Group=co2mon

RestartSec=10
StartLimitInterval=60
StartLimitBurst=3

#StandardOutput=syslog
#StandardError=syslog

[Install]
WantedBy=multi-user.target

File /etc/systemd/system/ycpusher.service:

[Unit]
Description=Read co2mon metrics and push to Yandex.Cloud Monitoring Service
After=network.target

[Service]
ExecStart=/usr/local/bin/ycpusher  -sa-key-file /home/co2mon/sa_key_2024.json -folder-id b1gXXXXXXX
Restart=always
User=co2mon
Group=co2mon

RestartSec=10
StartLimitInterval=60
StartLimitBurst=3


[Install]
WantedBy=multi-user.target

Apply and start:

sudo systemctl daemon-reload
sudo systemctl enable co2mon.service
sudo systemctl enable ycpusher.service

See also

• ZyAura ZG01C Module Manual
• RevSpace CO2 Meter Hacking
• Photos of the device and the circuit board