{"product_id":"sensy-co2-add-on","title":"Sensy-One CO₂ Add-on","description":"\u003cp\u003e The \u003cstrong\u003eSensy-One CO₂ Add-on\u003c\/strong\u003e is a plug-and-play expansion module for the \u003ca href=\"https:\/\/slimhuisje.nl\/products\/sensy-one-s1-pro-multi-sense\"\u003eSensy-One S1 Pro Multi Sense\u003c\/a\u003e and \u003ca href=\"https:\/\/slimhuisje.nl\/products\/e1-pro-multi-sense-mmwave-sensor-home-assistant\"\u003eE1 Pro Multi Sense\u003c\/a\u003e , equipped with the Sensirion SCD40 sensor. This module measures real CO₂ concentrations with professional NDIR (non-dispersive infrared) technology, instead of estimated values. This gives you accurate insight into the air quality for a healthy indoor climate. The module easily connects to the front of the S1 Pro or E1 Pro via a plug-and-play connector, without soldering or additional tools.\u003c\/p\u003e\n\n\u003ch4\u003e Why a separate CO₂ sensor?\u003c\/h4\u003e\n\n \u003cp\u003eThe standard BME688 sensor in the S1 Pro estimates CO₂ levels based on VOC (volatile compounds) measurements, which is suitable for general air quality monitoring. However, the SCD40 measures \u003cstrong\u003ereal CO₂ concentrations\u003c\/strong\u003e with high-quality technology, which is essential for healthy bedrooms, offices, and classrooms. Excessively high CO₂ levels (above 1000 ppm) lead to reduced concentration, fatigue, and poor sleep quality. With the SCD40, you get reliable measurements for optimal ventilation. For the \u003ca href=\"https:\/\/slimhuisje.nl\/products\/e1-pro-multi-sense-mmwave-sensor-home-assistant\"\u003eE1 Pro\u003c\/a\u003e , this add-on is the only way to measure CO₂, as this model does not have a built-in BME688.\u003c\/p\u003e\n\n\u003ch4\u003e Sensirion SCD40 Specifications\u003c\/h4\u003e\n\n \u003cp\u003eThe SCD40 is a compact, energy-efficient CO₂ sensor that uses photoacoustic NDIR technology. It measures CO₂ with an accuracy of \u003cstrong\u003e±50-100 ppm\u003c\/strong\u003e between 400 and 2000 ppm, delivering professional-quality results. The SCD40 also measures temperature (±0.8°C accuracy) and relative humidity (±6% accuracy). The sensor operates optimally between 0°C and 50°C and has a measurement range of 0-40,000 ppm CO₂. The SCD40 complies with the WELL Building Standard for healthy buildings.\u003c\/p\u003e\n\n\u003ch4\u003e Altitude compensation\u003c\/h4\u003e\n\n \u003cp\u003eA unique feature is automatic \u003cstrong\u003ealtitude compensation\u003c\/strong\u003e . In the \u003ca href=\"https:\/\/slimhuisje.nl\/products\/sensy-one-s1-pro-multi-sense\"\u003eS1 Pro,\u003c\/a\u003e the SCD40 uses pressure readings from the BME688 sensor to correct CO₂ measurements based on altitude and air pressure. The \u003ca href=\"https:\/\/slimhuisje.nl\/products\/e1-pro-multi-sense-mmwave-sensor-home-assistant\"\u003eE1 Pro\u003c\/a\u003e measures air pressure by default and uses the same compensation. This ensures accurate measurements whether you live at sea level or in a high-altitude area. Measurements remain reliable even in changing weather conditions.\u003c\/p\u003e\n\n\u003ch4\u003e Automatic Sensor Tuning\u003c\/h4\u003e\n\n \u003cp\u003eWith the \u003ca href=\"https:\/\/slimhuisje.nl\/products\/sensy-one-s1-pro-multi-sense\"\u003eS1 Pro\u003c\/a\u003e , temperature and humidity measurements from both the BME688 and SCD40 are automatically aligned using advanced correction algorithms. With the \u003ca href=\"https:\/\/slimhuisje.nl\/products\/e1-pro-multi-sense-mmwave-sensor-home-assistant\"\u003eE1 Pro,\u003c\/a\u003e the SCD40 provides the primary temperature and humidity measurements. This ensures accurate measurements without manual calibration, even when temperature fluctuates or sensor heating occurs.\u003c\/p\u003e\n\n\u003ch4\u003e Plug-and-Play Installation\u003c\/h4\u003e\n\n\u003cp\u003e The CO₂ Add-on connects to the plug-and-play connector on the \u003cstrong\u003efront\u003c\/strong\u003e of the S1 Pro or E1 Pro Multi Sense. No soldering, no extra tools – simply plug it in and you're ready to go. The module is automatically recognized by Home Assistant via ESPHome, and the CO₂ readings appear directly on your dashboard alongside other sensor values.\u003c\/p\u003e\n\n\u003ch4\u003e Measurement Interval and Responsiveness\u003c\/h4\u003e\n\n \u003cp\u003eThe SCD40 measures CO₂ every \u003cstrong\u003e5 seconds\u003c\/strong\u003e by default, but this interval is configurable in ESPHome. The sensor has a response time of approximately 60 seconds to CO₂ changes, which is fast enough for real-time ventilation automation. Power consumption is low (approximately 5 mA on average), which is ideal for continuous monitoring.\u003c\/p\u003e\n\n\u003ch4\u003e Compatibility and Integration\u003c\/h4\u003e\n\n\u003cp\u003e The CO₂ Add-on works with the \u003cstrong\u003e\u003ca href=\"https:\/\/slimhuisje.nl\/products\/sensy-one-s1-pro-multi-sense\"\u003eSensy-One S1 Pro Multi Sense\u003c\/a\u003e\u003c\/strong\u003e and the \u003cstrong\u003e\u003ca href=\"https:\/\/slimhuisje.nl\/products\/e1-pro-multi-sense-mmwave-sensor-home-assistant\"\u003eE1 Pro Multi Sense\u003c\/a\u003e\u003c\/strong\u003e and requires ESPHome firmware. The module integrates seamlessly with Home Assistant and can be used for automations such as ventilation activation when CO₂ levels are high, notifications for poor air quality, or graphs for long-term monitoring.\u003c\/p\u003e\n\n\u003ch4\u003e Calibration and Maintenance\u003c\/h4\u003e\n\n \u003cp\u003eThe SCD40 has a built-in automatic self-calibration (ASC) that periodically calibrates the sensor based on the lowest CO₂ value over a 7-day period (assuming regular ventilation to outside air with ~400 ppm CO₂). Manual calibration is possible but rarely necessary. The sensor is maintenance-free and has a lifespan of over 10 years under normal use.\u003c\/p\u003e\n\n\u003ch4\u003e Physical and Dimensions\u003c\/h4\u003e\n\n\u003cp\u003e The CO₂ Add-on is designed to be compact and fits seamlessly onto the front of the S1 Pro or E1 Pro PCB without disrupting the aesthetics.\u003c\/p\u003e\n\n\u003ch4\u003e Usage scenarios\u003c\/h4\u003e\n\n \u003cp\u003eThe CO₂ Add-on is ideal for \u003cstrong\u003ebedrooms\u003c\/strong\u003e (healthy sleep requires CO₂ below 1000 ppm), \u003cstrong\u003eoffices\u003c\/strong\u003e (productivity decreases at high CO₂ levels), \u003cstrong\u003eclassrooms\u003c\/strong\u003e (concentration and learning performance), \u003cstrong\u003emeeting rooms\u003c\/strong\u003e (CO₂ rises quickly with many people), and \u003cstrong\u003enurseries\u003c\/strong\u003e (healthy air for young children). Automations allow you to control fans, window switches, or HVAC systems based on CO₂ levels.\u003c\/p\u003e\n\n\u003ch4\u003e Plus points\u003c\/h4\u003e\n\n\u003cul\u003e\n\n\u003cli\u003e Accurate CO₂ measurements with professional NDIR technology (±50-100 ppm)\u003c\/li\u003e\n\n\u003cli\u003e Altitude compensation via BME688 (S1 Pro) or standard air pressure measurement (E1 Pro) for reliable measurements at any air pressure\u003c\/li\u003e\n\n\u003cli\u003e Plug-and-play installation without soldering or tools\u003c\/li\u003e\n\n\u003cli\u003e Compatible with both S1 Pro and E1 Pro Multi Sense\u003c\/li\u003e\n\n\u003cli\u003e Automatic self-calibration for long-term accuracy\u003c\/li\u003e\n\n\u003cli\u003e Low power consumption and more than 10 years lifespan\u003c\/li\u003e\n\n\u003cli\u003e Also measures temperature and humidity\u003c\/li\u003e\n\n\u003cli\u003e Complies with the WELL Building Standard for healthy buildings\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\n\u003ch4\u003e Negative points\u003c\/h4\u003e\n\n\u003cul\u003e\n\n \u003cli\u003eOnly works with Sensy-One S1 Pro or E1 Pro Multi Sense; not as a standalone sensor\u003c\/li\u003e\n\n\u003cli\u003e Requires Home Assistant and ESPHome firmware; limited support for other platforms\u003c\/li\u003e\n\n\u003cli\u003e Automatic calibration requires exposure to clean outside air (~400 ppm CO₂)\u003c\/li\u003e\n\n\n\u003c\/ul\u003e\n\n\u003ch4\u003e Frequently Asked Questions\u003c\/h4\u003e\n\n\u003ch5\u003e Does the CO₂ Add-on work without the S1 Pro or E1 Pro?\u003c\/h5\u003e\n\n\u003cp\u003e No, the CO₂ Add-on is designed exclusively for use with the \u003ca href=\"https:\/\/slimhuisje.nl\/products\/sensy-one-s1-pro-multi-sense\"\u003eSensy-One S1 Pro Multi Sense\u003c\/a\u003e or the \u003ca href=\"https:\/\/slimhuisje.nl\/products\/e1-pro-multi-sense-mmwave-sensor-home-assistant\"\u003eE1 Pro Multi Sense\u003c\/a\u003e . The module requires one of these sensors for power, communication with Home Assistant, and altitude compensation.\u003c\/p\u003e\n\n\u003ch5\u003e How do I connect the CO₂ Add-on?\u003c\/h5\u003e\n\n \u003cp\u003eThe module connects to the plug-and-play connector on the front of the S1 Pro or E1 Pro. No soldering or tools required – simply click the connector in and the sensor is automatically recognized by Home Assistant. CO₂ measurements appear instantly on your dashboard.\u003cbr\u003e TIP: Watch \u003ca href=\"https:\/\/www.youtube.com\/watch?v=s2bCj49uFjw\" title=\"Meet the Sensy-One S1 Pro: Presence, Air Quality, Light \u0026amp; More!\" rel=\"noopener\" target=\"_blank\"\u003ethis video\u003c\/a\u003e showing the installation.\u003c\/p\u003e\n\n\u003ch5\u003e Do I need to calibrate the CO₂ sensor?\u003c\/h5\u003e\n\n\u003cp\u003e No, the SCD40 has an automatic self-calibration (ASC) that periodically calibrates the sensor based on the lowest CO₂ reading in 7 days. This works well if the room is regularly ventilated with outside air (~400 ppm CO₂). Manual calibration is possible via ESPHome, but is rarely necessary.\u003c\/p\u003e\n\n\u003ch5\u003e What is the difference between the BME688 (S1 Pro) and the SCD40 for CO₂ measurement?\u003c\/h5\u003e\n\n \u003cp\u003eThe BME688 in the \u003ca href=\"https:\/\/slimhuisje.nl\/products\/sensy-one-s1-pro-multi-sense\"\u003eS1 Pro\u003c\/a\u003e estimates CO₂ levels based on VOC (volatile compounds) measurements, which is suitable for general air quality. The SCD40 measures real CO₂ concentrations with NDIR technology and offers professional-grade accuracy (±50-100 ppm). For healthy bedrooms, offices, and classrooms, the SCD40 is the better choice. The \u003ca href=\"https:\/\/slimhuisje.nl\/products\/e1-pro-multi-sense-mmwave-sensor-home-assistant\"\u003eE1 Pro\u003c\/a\u003e does not include the BME688, so this add-on is the only way to measure CO₂.\u003c\/p\u003e\n\n\u003ch5\u003e What is altitude compensation and why is it important?\u003c\/h5\u003e\n\n\u003cp\u003e CO₂ measurements are affected by air pressure, which varies with altitude and weather conditions. The SCD40 uses pressure readings from the BME688 (with the S1 Pro) or the standard air pressure measurement (with the E1 Pro) to automatically correct measurements. This ensures accurate CO₂ readings whether you live at sea level or at high altitudes, and in changing weather conditions.\u003c\/p\u003e\n\n \u003ch5\u003eHow quickly does the CO₂ sensor respond to changes?\u003c\/h5\u003e\n\n\u003cp\u003e The SCD40 measures every 5 seconds and has a response time of approximately 60 seconds to CO₂ changes. This is fast enough for real-time ventilation automation, for example, switching on a fan when CO₂ rises above 1000 ppm.\u003c\/p\u003e\n\n\u003ch5\u003e Can I use the CO₂ Add-on with Google Home or Alexa?\u003c\/h5\u003e\n\n\u003cp\u003e Not directly. The CO₂ Add-on works exclusively through Home Assistant and ESPHome. You can, however, connect Home Assistant to Google Home or Alexa, giving you indirect access to CO₂ readings through those platforms.\u003c\/p\u003e\n\n\u003ch5\u003e What's the difference between the S1 Pro and E1 Pro with this add-on?\u003c\/h5\u003e\n\n \u003cp\u003eWith the CO₂ Add-on, you get the same accurate CO₂ measurements on both sensors. The difference lies mainly in the other features: the \u003ca href=\"https:\/\/slimhuisje.nl\/products\/sensy-one-s1-pro-multi-sense\"\u003eS1 Pro\u003c\/a\u003e has a BME688 for VOC\/IAQ measurements and USB-C power, while the \u003ca href=\"https:\/\/slimhuisje.nl\/products\/e1-pro-multi-sense-mmwave-sensor-home-assistant\"\u003eE1 Pro\u003c\/a\u003e offers PoE support and uses an LD2460 mmWave sensor with ceiling and wall modes. Both sensors offer excellent CO₂ monitoring with this add-on installed.\u003c\/p\u003e","brand":"Sensy-One","offers":[{"title":"Default Title","offer_id":51671819419990,"sku":null,"price":29.95,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0731\/5921\/3398\/files\/S1ProSCD40_position_view.png?v=1769740853","url":"https:\/\/slimhuisje.nl\/en\/products\/sensy-co2-add-on","provider":"slimhuisje.nl","version":"1.0","type":"link"}