provides a simple, 'free and open source' database system for storage and retrieval of CO2 sensor data.

  • - Easy to set up
  • - Send data from any device via HTTP POST
  • - Access data as graphs, CSV, or JSON
  • - Source code available (GPL 3.0)
  • - Funded on a pay-as-you-can basis via Open Collective -- Cheers!
  • is compatible with a wide variety of microcontroller hardware -- including our Open Hardware CO2 Monitoring Kit (CERN Open Hardware License v2), which you can build yourself or buy pre-assembled from

    1. Create a new CO2 data feed

    Enter a name for your new feed, and you'll be provided with your new feed's PUBLIC KEY and PRIVATE KEY. Copy them down somewhere safe! (Read more about this here.)

    Create a New CO2 Data Feed

    2. Send CO2 data to your new feed

    ... via the browser (quick test):

    You can send test CO2 data to your new feed by entering your feed's PUBLIC KEY and PRIVATE KEY:

    Send Test Data To Your CO2 Data Feed

    ... or via your favorite hardware:

    A wide variety of microcontrollers, CO2 sensors, and programming frameworks can be used to send data to Bayou-CO2. You can read (or contribute to!) guidelines for doing this here.

    ... or via our DIY hardware design:

    We have developed an Open Hardware CO2 monitoring kit, based on the popular WiFi+Bluetooth Espressif ESP32 microcontroller and the Sensiron SCD30 CO2 sensor. The design files and assembly guides are all available (CERN Open Hardware License v2), or you can purchase one pre-assembled and pre-programmed to send data to Bayou-CO2.

    Build or Purchase a PVOS CO2 Monitoring Kit

    3. View your CO2 data

    ... via a form:

    Or, you can enter your PUBLIC KEY in the form below to go to its home page. At the feed's home page, you'll find links to graphs, JSON, and CSV for the feed data.

    View an Existing CO2 Data Feed

    ... or via simple links:

    You can retrieve CO2 data (as graphs, JSON, and CSV) using your feed's PUBLIC KEY. They'll always be available (and free for you to share) at the following links:

    Feed Home:[PUBLIC KEY]

    Feed as JSON:[PUBLIC KEY]/json

    Feed as CSV:[PUBLIC KEY]/csv