Adafruit
STCC4 + SHT41 CO2, Temperature & Humidity Sensor
· MPN: ADA6478
This compact breakout combines the STCC4 CO2 sensor with a Sensirion SHT41 temperature and humidity sensor for convenient indoor air monitoring. The STCC4 me...
This compact breakout combines the STCC4 CO2 sensor with a Sensirion SHT41 temperature and humidity sensor for convenient indoor air monitoring. The STCC4 measures true CO2 using a thermal conductivity method rather than estimating from VOCs, and the onboard SHT41 helps improve the CO2 measurement while also giving you accurate ambient temperature and humidity data.
The board is designed for small builds, with the STCC4 itself measuring just 4 x 3 x 1.2mm, and it includes the support circuitry needed for easy use over I2C. The SHT41 is connected to the STCC4's secondary I2C port, so you only need to query the STCC4 to read the measurements instead of managing two separate sensor interfaces.
For quick prototyping, there are SparkFun Qwiic-compatible STEMMA QT connectors fitted for solderless I2C connections. A QT cable is not included. If you prefer breadboarding, each board comes fully assembled and tested with a small strip of header that you can solder on in a few minutes.
Adafruit provides Arduino and CircuitPython/Python library support, so it can be used with a wide range of microcontrollers and single-board computers, including Raspberry Pi. As with other true CO2 sensors, it should be exposed to outdoor air about once a week for self-calibration to a 400 ppm baseline. This sensor is tuned for indoor air measurement rather than scientific CO2 analysis or unusual gas mixtures.
Features:
- Measurement principle: Thermal conductivity measurement principle
- Interface: Digital I2C interface and calibrated output signal
- Address options: Configurable I2C address, default 0x64 can be set to 0x65
- I2C support: I2C fast mode plus, CRC checksum
- Condensing environments: Fully functional in condensing environment
- Heater: Variable power heater
- Traceability: NIST traceability for sensor
- Qualification: JEDEC JESD47 qualification for sensor
- Technology: Mature technology from global market leader Sensirion
Specifications:
- STCC4 sensor size: 4 x 3 x 1.2mm
- CO2 measurement accuracy: ±(100 ppm + 10%) from 400 – 5,000 ppm
- Avg. current consumption: below 100 µA in single shot measurement mode
- Relative humidity accuracy: up to ±1.8 %RH
- Temperature accuracy: up to ±0.2 °C
- Breakout supply voltage: 3.3 to 5V
- Average bare sensor current: 0.4 μA (at meas. rate 1 Hz)
- Idle bare sensor current: 80 nA
- Operating range: 0…100 %RH, -40…125 °C
- I2C address: 0x44
A handy choice for room air monitoring, ventilation projects, smart home logging, and compact embedded builds that need CO2, temperature, and humidity over I2C.
Jargon buster
Plain-language definitions for the technical terms used above.
- breakout
- A breakout is a small circuit board that makes a tiny or hard-to-solder component easier to connect to with standard pins. It matters because this OLED module can be wired into a microcontroller project without needing to solder directly to the display’s fine contacts.
- CircuitPython
- A beginner-friendly version of Python designed to run directly on microcontroller boards. If a product supports CircuitPython, you can often program it by copying code files onto the board rather than setting up a more complex toolchain.
- I2C
- I2C is a two-wire communication bus used by many sensors and small modules. It matters because several I2C devices can share the same two wires, but each device needs a compatible address and your controller must support I2C.
- I2C address
- An I2C address is the number a device uses so a microcontroller can tell it apart from other devices on the same I2C bus. It matters because two devices with the same fixed address may conflict if used together.
- NIST traceability
- A way of linking a measurement back to standards maintained by the US National Institute of Standards and Technology. For temperature sensing, it matters when you need documented confidence that readings can be compared to recognised measurement standards.
- ppm
- ppm means parts per million, a common way to express very small gas concentrations in air. For CO₂ sensors, the ppm range tells you what levels the sensor can measure, such as normal indoor air through to poorly ventilated spaces.
- Qwiic
- Qwiic is a plug-in connector system for I2C devices that uses small 4-pin cables, so you can connect compatible sensors without soldering. It matters because your controller or adapter also needs Qwiic, or you will need a cable or breakout to wire it up.
- STCC4
- STCC4 is the specific Sensirion gas-sensing chip used on this module to measure carbon dioxide. Knowing the chip helps you find compatible libraries, datasheets, and performance details before using it in a project.
- STEMMA QT
- A small plug-in connector system for I2C boards that lets you connect compatible sensors and controllers without soldering. It matters because it can make wiring faster and less error-prone, especially when adding several small modules to a project.
- Thermal conductivity measurement
- Thermal conductivity measurement estimates gas concentration by detecting how well the surrounding air conducts heat. For a CO₂ sensor, this tells you the module is using a direct physical sensing method rather than estimating CO₂ from other air-quality signals.
Find this product in
STCC4 Datasheet
Datasheet · 743.8 KB · Click any page to view full size
Supplier page — adafruit.com
Supplier Description · 1020.2 KB · Click any page to view full size
SHT41 Datasheet
Datasheet · 915.1 KB · Click any page to view full size
