Story
This project is an updated design of this older (https://github.com/mike-rankin/ESP32-S3_CO2_Monitor) CO2 monitor using the new STCC4 sensor from Sensirion. For years I've been using the larger SCD40 that was difficult to fit into smaller designs because of it's large size. Below you can see the size differences between the two.
The SCD40 measures co2 from 400ppm to 2000ppm +/-50ppm in a 10.1mm x 10.1mm footprint and the STCC4 measures from 400ppm to 5000ppm +/-100ppm in a 3mm x 4mm footprint.
This custom board designed in Altium is powered by a USB-C phone charger and is the same size as the display using as few parts as possible. A few features I've added are backlight control for dimming, a Qwiic i2c connector for adding other sensors and sensors on the front side. Problems with this design are the delicate push and pull stress on the USB-C connector. Any side to side push on the board while powered up will easily break the connector off the board. The other is the temperature value displayed. The STCC4 has a built in heater and this combined with heat generated by the backlight, the ESP32 running at full speed and the copper pour on the top and bottom all up the temperature displayed.
When sourcing parts, remember to order the correct SHT40 needed for STCC4 temperature and humidity compensation. This part connects directly to the STCC4, must be as close as possible and must have an i2c address of 0x44. A sensor with a different address will be ignored.
Pricing for components in small quantities are:
STCC4 - Digi-Key $8.27
SHT40-AD1B-R3 - Digi-Key $1.80
C3001294 (USB-C) - LCSC $0.52
C5736265 (ESP32-C6) - LCSC $4.57 ER-TFT1.28-2 (LCD) - BuyDisplay $8.41
Custom design work may be possible if you have a project in mind that you would like to see put together. Feel free to reach me on X @mikerankin or by email at 0miker0@gmail.com
More details: https://github.com/mike-rankin/ESP32-C6_CO2_Monitor. This is GitHub account: https://github.com/mike-rankin where you will explore more excellent projects. He is a good DIY maker who designs custom ESP32 IoT projects using Altium Designer, Arduino IDE and Fusion360. Welcome everyone to follow.
