Skip to the beginning of the images gallery

CO2 Sensor - STC31 (Qwiic)

SKU: SPX-18385 Brand: Sparkfun

Do you need to be able to sense CO2 concentrations of up to 100%? If so, the STC31 is the sensor for you! The Sensirion STC31 thermal conductivity sensor h...

$179.95 AUD, inc GST

$163.59 AUD, exc GST

Quantity Discounts:

5-10 $158.68 (exc GST)
10+ $155.41 (exc GST)

Out of Stock

Do you need to be able to sense CO₂ concentrations of up to 100%? If so, the STC31 is the sensor for you! The Sensirion STC31 thermal conductivity sensor has two CO₂ measurement ranges: 0 to 25 vol%; and 0 to 100 vol%. The measurement repeatability is 0.2 vol%, with a stability of 0.025 vol% / °C. The measurement accuracy depends on the measurement range: 0.5 vol% + 3% measured value; 1 vol% + 3% measured value.

Our breakout includes a separate SHTC3 humidity and temperature sensor; allowing the STC31 to deliver humidity-compensated measurements together with improved temperature compensation. The STC31 can compensate for atmospheric pressure too - which is handy if, like us, you’re up in the mountains!

The STC3x sensor family is Sensirion’s series of Gas Concentration sensors designed for high-volume applications. The STC3x utilizes a revolutionized thermal conductivity measurement principle, which results in superior repeatability and long-term stability. This makes the STC31 a perfect choice for applications where reliability is key.

The outstanding performance of these sensors is based on Sensirion’s patented CMOSens® sensor technology, which combines the sensor element, signal processing and digital calibration on a small CMOS chip. The well-proven CMOS technology is perfectly suited for high-quality mass production and is the ideal choice for demanding and cost-sensitive OEM applications.

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.

As usual, our board includes a power LED, a pair of Qwiic connectors, I²C breakout pads and pull-up resistors. You can disable the LED and pull-ups if you need to by cutting the I2C jumpers on the back of the board.

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.

The SparkFun Qwiic Connect System is an ecosystem of I²C sensors, actuators, shields and cables that make prototyping faster and less prone to error. All Qwiic-enabled boards use a common 1mm pitch, 4-pin JST connector. This reduces the amount of required PCB space, and polarized connections mean you can’t hook it up wrong.

Experimental Product: SparkX products are rapidly produced to bring you the most cutting edge technology as it becomes available. These products are tested but come with no guarantees. Live technical support is not available for SparkX products. Head on over to our forum for support or to ask a question.

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)

This product is listed in:

Sensors>Gas & Smoke

Product Comments

Start the conversation

Exact shipping can be calculated on the view cart page (no login required).

Products that weigh more than 0.5 KG may cost more than what's shown (for example, test equipment, machines, >500mL liquids, etc).

We deliver Australia-wide with these options (depends on the final destination - you can get a quote on the view cart page):

$3+ for Stamped Mail (typically 10+ business days, not tracked, only available on selected small items)
$7+ for Standard Post (typically 6+ business days, tracked)
$11+ for Express Post (typically 2+ business days, tracked)
Pickup - Free! Only available to customers who live in the Newcastle region (must order online and only pickup after we email to notify you the order is ready). Orders placed after 2PM may not be ready until the following business day.

Non-metro addresses in WA, NT, SA & TAS can take 2+ days in addition to the above information.

Some batteries (such as LiPo) can't be shipped by Air. During checkout, Express Post and International Methods will not be an option if you have that type of battery in your shopping cart.

International Orders - the following rates are for New Zealand and will vary for other countries:

$12+ for Pack and Track (3+ days, tracked)
$16+ for Express International (2-5 days, tracked)

If you order lots of gear, the postage amount will increase based on the weight of your order.

Our physical address (here's a PDF which includes other key business details):

Unit 18, 132 Garden Grove Parade
Adamstown
NSW, 2289
Australia

Take a look at our customer service page if you have other questions such as "do we do purchase orders" (yes!) or "are prices GST inclusive" (yes they are!). We're here to help - get in touch with us to talk shop.

Have a product question? We're here to help!