After many long months of testing, and housing design, we got a commercial sensor for comparison testing in the last step, and we are more than satisfied with the final result, and now we are sharing this compact CO2 sensor.  

Its basic characteristics are as follows:

- Based on SCD40 chip from Sensirion, Switzerland.

    - Operating temperature: -10 degrees - 60 degrees

    - Operating humidity: 0 - 95%.

    - Measurement accuracy within ± (50 ppm +5%)

    - Measurement range: 0 - 40 000ppm

    - Imaging time: 60s

    - Operating life: more than 10 years

    - Operating current: 15ma (we work in 3.3V mode)

The size of the sensor is quite small (but not 1U small), similar to BP1, it is a rectangle, we try to hide the sensor as much as possible, but reveal the detection unit. We wanted to have enough space inside for the ESP32's temperature to dissipate, and chose the ESP32-C3 transmission module with a pretty good WIFI signal (same as the 2A).

Our understanding of CO2 is that it can build up in an enclosed space, and the ideal value is 1000 ppm or less, and when it gets higher you feel dull and dizzy. We don't have a lot of intuition for this which is our general understanding.

The SCD40 carries temperature and humidity, but due to the effects of the ESP32's own heat generation, the temperature can be way off, and we would not recommend adopting the values in it. (We are looking at developing a Zigbee version in the future, which would still require an external power supply, but the temperature effect would be eliminated.)

The sensor is based on ESPHome, and like all of our sensors, HA integrates directly and discovers the device as soon as it is paired to the network, and the whole process can be done in less than half a minute (powering up the sensor, connecting to the sensor's hotspot, SCO2-SENSOR, configuring WIFI, and auto-discovering the device in HA).  

It's simple, but it's also cool in my opinion.

Due to the initial manufacturing, our manufacturing time will be 2-4 days. And due to the high cost of the core sensor, it will be hard for us to bring down the final selling price, but for the first users, we are offering a 20% discount and inviting you to explore this CO2 sensor.