Software for CO2 Monitor

Compatible Devices

This software supports compact USB-powered CO2 meters that identify as:

  idVendor           0x04d9 Holtek Semiconductor, Inc.
  idProduct          0xa052 USB-zyTemp

A of 2023, there are two revisions of these product on the market, that can be distinguished by its serial and release numbers:

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
                    old        new
――――――――――――――――――――――――――――――――――
serial_number      1.40       2.00
release_number   0x0100     0x0200
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

(where serial_number == iSerial and release_number == bcdDevice)

The co2mon software tries to auto-detect them, but its also possible to override the detection (cf. the -N and -n options).

Note that these devices are rebranded by vendors such as TFA and thus are available online under different product names (e.g. sold by Amazon, as of 2023). Even if one user reported success with a certain product, the vendor might have silently switched to a completely different and unsupported hardware without changing the product name, at any time.

List of user reported devices that worked in the past:

TFA AIRCO2NTROL MINI CO2 Monitor (EAN 4009816027351), via Amazon.de, 2023

Installation

Arch Linux

There is PKGBUILD in AUR. The simplest way to install is using yaourt:

yaourt -S co2mon-git

Fedora GNU/Linux and RHEL/CentOS/Scientific Linux

co2mon packages can be installed from official repo:

dnf install co2mon

From Source

# macOS
brew install cmake pkg-config hidapi

# Ubuntu
apt-get install cmake g++ pkg-config libhidapi-dev

mkdir build
cd build
cmake ..
make
./co2mond/co2mond

dmage/co2mon