{"product_id":"adafruit-stcc4-and-sht41-co2-temperature-humidity-sensor-ada6478","title":"Adafruit STCC4 and SHT41 - CO2, Temperature \u0026 Humidity Sensor","description":"\u003cstyle type=\"text\/css\"\u003e.product-info-tutorial{margin-bottom:20px;}.product-tutorial-img-container{width:20%;}.product-tutorial-img-container img{margin:0;}\u003c\/style\u003e\u003c?xml version=\"1.0\" standalone=\"yes\"?\u003e\n\n\u003csection id=\"description\" class=\"prod-accordion-content prod-accordion-content-description mobile-text-wrapper\" aria-labelledby=\"tab-description-heading\"\u003e\u003cdiv class=\"tab-heading-row\"\u003e\n\t\t\t\t\u003ch2 id=\"tab-description-heading\"\u003e\n\t\t\t\t\t\t\t\t\t\t\tDescription\t\t\t\t\t\t\t\t\t\u003c\/h2\u003e\n\t\t\t\u003c\/div\u003e\n\t\t\t\u003cdiv id=\"tab-description-content\" class=\"panel-collapse collapse in\"\u003e\n\t\t\t\t\u003cp\u003eCO₂ sensors are essential for determining if a room is too 'stuffy' - high CO₂ makes humans grumpy and tired. That's why it's always nice to take a deep breath outside where CO₂ is about 400 ppm. However, until now, CO₂ sensors were always really chunky (\u003ca href=\"https:\/\/www.adafruit.com\/product\/4867\"\u003elike the SCD-30\u003c\/a\u003e) or pricey (\u003ca href=\"https:\/\/www.adafruit.com\/product\/5187\"\u003elike the SCD-40\u003c\/a\u003e). \u003ca href=\"https:\/\/www.pakronics.com.au\/products\/ADA3709\"\u003eInexpensive sensors like the SGP30 approximate the CO₂ using VOC gas concentration\u003c\/a\u003e, but they don't actually measure CO₂.\u003c\/p\u003e\n\u003cp\u003eThe STCC4 is a tiny (4 x 3 x 1.2mm) sensor that can measure CO₂ gas and fit in just about any enclosure. It uses thermal conductivity (TC) instead of NDIR or photoacoustic measurements. TC is based on the inherent thermal conductivity of all gases. With a thorough understanding of the gas composition in ambient environments, subtle changes in gas concentrations can be detected. The measurement principle is based on heating the air within a measurement cavity and sensing the heat transfer with a temperature sensor. \u003ca href=\"https:\/\/www.youtube.com\/watch?v=5mJqpmBHUV0\"\u003eFor more details check out the EYE ON NPI video we did on this sensor!\u003c\/a\u003e\u003c\/p\u003e\n\u003cp\u003eThe trade-off for the small size and lower cost is that STCC4 is that it's really tuned just for indoor air measurement applications - not for scientific CO₂ sensing or where the air gas composition is 'abnormal'. That said, the vast majority of use cases we see are indoor air monitoring to reduce illness and stuffiness and for that purpose the STCC4 is great!\u003c\/p\u003e\n\u003cp\u003eOne thing to note, like all true CO₂ sensors, it must be self-calibrated by having it exposed to outdoor air once a week, to get a baseline 400 ppm measurement - in practice that means opening a window or making sure fresh air gets to the sensor.\u003c\/p\u003e\n\u003cp\u003eTo round the STCC4 out and make it a perfect nini indoor air quality sensor, \u003ca href=\"https:\/\/www.pakronics.com.au\/products\/ADA5776\"\u003ewe've added an SHT41 as well\u003c\/a\u003e to improve the CO₂ measurements. The SHT41 has an excellent ±1.8% typical relative humidity accuracy from 25 to 75% and ±0.2 °C typical accuracy from 0 to 75 °C. Note it is connected to the secondary I2C port on the STCC4 so that you only have to query the STCC4 to get measurements rather than talk to both chips with two libraries.\u003c\/p\u003e\n\u003cp\u003eSuch a lovely pair of chips - so we spun up a breakout board with the STCC4 + SHT41 and some supporting circuitry such as pullup resistors and capacitors. To make things even easier, we've included\u003ca href=\"https:\/\/www.sparkfun.com\/qwiic\"\u003e SparkFun Qwiic\u003c\/a\u003e compatible\u003ca href=\"https:\/\/learn.adafruit.com\/introducing-adafruit-stemma-qt\"\u003e STEMMA QT\u003c\/a\u003e connectors for the I2C bus so you don't even need to solder! \u003ca href=\"https:\/\/www.adafruit.com\/?q=stemma+qt+cable\u0026amp;sort=BestMatch\"\u003eQT Cable is not included, but we have a variety in the shop\u003c\/a\u003e. \u003c\/p\u003e\n\u003cp\u003eIf you prefer working on a breadboard, each order comes with one fully assembled and tested PCB breakout and a small piece of header. You'll need to solder the header onto the PCB, but it's fairly easy and takes only a few minutes even for a beginner.\u003c\/p\u003e\n\u003cp\u003eWe've written both Arduino and CircuitPython\/Python library code for this chip, so you can use it with just about any microcontroller or single-board computer like Raspberry Pi.\u003c\/p\u003e\t\t\t\u003c\/div\u003e\n\t\t\u003c\/section\u003e\u003cbr\u003e\u003cbr\u003e\u003csection id=\"technical-details\" class=\"prod-accordion-content prod-accordion-content-technical-details mobile-text-wrapper\" aria-labelledby=\"tab-technical-details-heading\"\u003e\u003cdiv class=\"tab-heading-row\"\u003e\n\t\t\t\t\u003ch2 id=\"tab-technical-details-heading\"\u003e\n\t\t\t\t\t\t\t\t\t\t\tTechnical Details\t\t\t\t\t\t\t\t\t\u003c\/h2\u003e\n\t\t\t\u003c\/div\u003e\n\t\t\t\u003cdiv id=\"tab-technical-details-content\" class=\"panel-collapse collapse in\"\u003e\n\t\t\t\t\u003cdiv class=\"row\"\u003e\r\n    \u003cdiv class=\"col-lg-12 col-md-12 col-sm-12 col-xs-12\"\u003e\n\u003cp\u003e\u003cstrong\u003eSTCC4 Specifications \u0026amp; Features\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eThermal conductivity measurement principle\u003c\/li\u003e\n\u003cli\u003eCO2 measurement accuracy ±(100 ppm + 10%) from 400 – 5,000 ppm\u003c\/li\u003e\n\u003cli\u003eDigital I2C interface and calibrated output signal\u003c\/li\u003e\n\u003cli\u003eAvg. current consumption below 100 µA in single shot measurement mode\u003c\/li\u003e\n\u003cli\u003eConfigurable I2C address, default 0x64 can be set to 0x65\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eSHT41 Specifications \u0026amp; Features\u003c\/strong\u003e\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eRelative humidity accuracy: up to ±1.8 %RH\u003c\/li\u003e\n\u003cli\u003eTemperature accuracy: up to ±0.2 °C\u003c\/li\u003e\n\u003cli\u003eBreakout supply voltage: 3.3 to 5V\u003c\/li\u003e\n\u003cli\u003eAverage bare sensor current: 0.4 μA (at meas. rate 1 Hz)\u003c\/li\u003e\n\u003cli\u003eIdle bare sensor current: 80 nA\u003c\/li\u003e\n\u003cli\u003eI2C fast mode plus, CRC checksum\u003c\/li\u003e\n\u003cli\u003eOperating range: 0…100 %RH, -40…125 °C\u003c\/li\u003e\n\u003cli\u003eFully functional in condensing environment\u003c\/li\u003e\n\u003cli\u003eVariable power heater\u003c\/li\u003e\n\u003cli\u003eNIST traceability for sensor\u003c\/li\u003e\n\u003cli\u003eJEDEC JESD47 qualification for sensor\u003c\/li\u003e\n\u003cli\u003eMature technology from global market leader Sensirion\u003c\/li\u003e\n\u003cli\u003eI2C address 0x44\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\r\n  \u003c\/div\u003e\n\u003cdiv class=\"row\"\u003e\n\u003cdiv class=\"col-lg-2 col-md-3 col-sm-3 col-xs-4\"\u003e\u003cimg src=\"\/\/www.adafruit.com\/includes\/templates\/shop2019\/images\/RoHS2_2011_65_EU.svg\" alt=\"RoHS 2 2011 65 EU Compliant\" width=\"145\" height=\"80\"\u003e\u003c\/div\u003e\n\u003cdiv class=\"col-lg-2 col-md-3 col-sm-3 col-xs-4\"\u003e\u003cimg src=\"\/\/www.adafruit.com\/includes\/templates\/shop2019\/images\/RoHS2_2015_863_EU.svg\" alt=\"RoHS 2 2015 863 EU Compliant\" width=\"145\" height=\"80\"\u003e\u003c\/div\u003e\n\u003c\/div\u003e\t\t\t\u003c\/div\u003e\n\t\t\u003c\/section\u003e\u003cbr\u003e\u003cbr\u003e\n","brand":"Adafruit","offers":[{"title":"Local stock","offer_id":42327768727634,"sku":"ADA6478","price":50.29,"currency_code":"AUD","in_stock":true},{"title":"Overseas stock","offer_id":42327768760402,"sku":"ADA6478","price":50.29,"currency_code":"AUD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0735\/0383\/files\/6478-02.jpg?v=1773325423","url":"https:\/\/www.pakronics.com.au\/products\/adafruit-stcc4-and-sht41-co2-temperature-humidity-sensor-ada6478","provider":"Pakronics®","version":"1.0","type":"link"}