co2mon

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A driver for the Holtek CO₂ USB monitors, tested using a TFA-Dostmann AIRCO2TROL MINI sensor.

Permissions

On Linux, you need to be able to access the USB HID device. For that, you can save the following udev rule to /etc/udev/rules.d/60-co2mon.rules:

text ACTION=="add|change", SUBSYSTEMS=="usb", ATTRS{idVendor}=="04d9", ATTRS{idProduct}=="a052", MODE:="0666"

Then reload the rules and trigger them:

shell udevadm control --reload udevadm trigger

Note that the udev rule above makes the device accessible to every local user.

Quick start

shell cargo run --example watch

Releases

Release notes are available in CHANGELOG.md.

Protocol

The USB HID protocol is not documented, but was reverse-engineered before.

The implementation was inspired by this one.

License

This project is licensed under either of

• Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
• MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.