SparkFun CO2 Sensor - STC31 (Qwiic)

SKU: SEN-29260 Brand: Sparkfun

Need to measure high concentrations of carbon dioxide? When standard CO2 sensors won't cut it, the SparkFun Qwiic STC31 Sensor is your solution. This...

$240.20 AUD, inc GST

$218.36 AUD, exc GST

Out of Stock

Need to measure high concentrations of carbon dioxide? When standard CO₂ sensors won't cut it, the SparkFun Qwiic STC31 Sensor is your solution. This powerful sensor from Sensirion is designed to measure CO₂ concentrations all the way up to a staggering 100% volume!

The STC31 is built for applications where reliability is key. It uses a revolutionary thermal conductivity measurement principle, combined with Sensirion's patented CMOSens® technology, to deliver superior repeatability and long-term stability. This means the sensor element, signal processing, and digital calibration are all integrated onto a single tiny chip.

Expected CO₂ Accuracy Ranges

Two CO₂ Measurement Ranges: 0 to 25 vol% and 0 to 100 vol%
Measurement Repeatability: 0.2 vol%
Accuracy (0-25% range): 0.5 vol% + 3% of measured value
Accuracy (0-100% range): 1 vol% + 3% of measured value

For best-in-class performance, we've integrated a separate SHTC3 humidity and temperature sensor right on the board. This allows the STC31 to provide fully compensated CO₂ measurements that also account for atmospheric pressure — a crucial feature for reliable data, which is handy if, like us, you’re up in the mountains!

Plug-and-Play with Qwiic

As part of the SparkFun Qwiic Connect System, this board is incredibly easy to use. Simply plug it into your development board with a Qwiic cable and you're ready to go—no soldering required! For advanced users, the STC31’s I²C address can be configured using the split-pad jumpers on the back of the board. The SHTC3’s I²C address is non-configurable; you will need a Qwiic Mux if you want to connect multiple sensors to the same bus.

Our Arduino library contains example sketches for the Arduino IDE to get you up and running quickly. It can be downloaded through the Arduino Library manager: search for 'SparkFun STC3x', or it can be found in the Documents tab above.

Features & Specs

Sensirion STC31 CO₂ Sensor
- Thermal conductivity sensor provides calibrated gas concentration and temperature output
- Calibrated for: CO₂ in N2; and CO₂ in air
- Measurement ranges: 0 to 25 vol%; 0 to 100 vol%
- Accuracy: 0.5 vol% + 3% measured value; 1 vol% + 3% measured value
- Repeatability: 0.2 vol%
- Temperature measurement range: -20 °C to +85 °C
- Concentration and temperature resolution: 16-bit
- Start-up time: 14 ms
- I²C address (configurable): 0x29 (default), 0x2A, 0x2B, 0x2C
- Supply Voltage: 2.7V_Min, 3.3V_Typ, 5.5V_Max
- Note: Qwiic bus operates at 3.3V_Max
Sensirion SHTC3 Humidity and Temperature Sensor
- Allows the STC31 to compensate for humidity and temperature
- Typical accuracy: ±2 %RH and ±0.2 °C
- Specified humidity range (extended): 0 to 100 %RH
- Specified temperature range: -40 °C to +125 °C
- I²C address (non-configurable): 0x70
- Supply Voltage: 1.62V_Min, 3.3V_Typ, 3.6V_Max
- Note: Qwiic bus operates at 3.3V_Max
Dual Qwiic connectors
Power LED (configurable)
I²C pull-ups (configurable)

Documentation

Schematic
KiCad Files
Hookup Guide
Datasheets:
- STC31
- SHTC3
STC Field Calibration Guide
STC Design-In Guide
Libraries:
- Arduino Library
- Python / MicroPython / CircuitPython Package
GitHub Hardware Repo

WARNING: This product may contain chemicals known to the State of California to cause cancer and birth defects or other reproductive harm. See link below for more information. www.P65Warnings.ca.gov

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