1. Product Overview
The SCD40-D-R2, developed by Sensirion, is a miniature carbon dioxide (CO₂) sensor leveraging photoacoustic NDIR (Non-Dispersive Infrared) technology. It integrates temperature and humidity sensing within a compact MEMS-based architecture, offering a package size of just 10.1 × 10.1 × 6.5 mm. With high resistance to contamination and high integration density, this sensor is ideal for embedded systems where space and power constraints are critical. The SCD40-D-R2 provides long-term stability, compactness, and multi-parameter environmental monitoring.
2. Key Technical Specifications
Parameter | Specification |
CO₂ Measurement Range | 400 – 2000 ppm (extendable to 5000 ppm in extended mode) |
Measurement Accuracy | ±(50 ppm + 5% of reading) |
Temperature & Humidity | Integrated sensing modules |
Interface | I²C digital communication (up to 1 MHz clock rate) |
Supply Voltage | 2.4 – 3.6 V |
Average Power Consumption | 3.5 mA (typical, at 1 measurement/5 seconds) |
Package Dimensions | 10.1 × 10.1 × 6.5 mm |
Mounting Type | Surface-Mount (SMD) |
Operating Temperature | -10°C to +60°C |
Auto Calibration | ASC (Automatic Self-Calibration) |
3. Measurement Principle
The SCD40 series employs a photoacoustic infrared (NDIR) measurement method. An IR light source excites CO₂ molecules inside a sealed cavity, generating periodic pressure waves. These are detected by an integrated MEMS microphone and converted into electrical signals. This design eliminates the need for a traditional optical path, enabling a compact form factor and enhanced resistance to dust and light-source drift.
4. Product Line Comparison
Model | CO₂ Range | Outputs | Accuracy | Calibration | Target Applications |
SCD40-D-R2 | 400–2000 ppm (up to 5000 ppm) | CO₂, Temp, RH | ±(50 ppm + 5%) | ASC | General-purpose embedded air quality monitoring |
400–5000 ppm | CO₂, Temp, RH | ±(40 ppm + 5%) | ASC & ASC+ | Industrial/high-CO₂ environments | |
400–2000 ppm | CO₂, Temp, RH | ±(50 ppm + 5%) | ASC | Stable environments with minimal CO₂ fluctuation |
Note: All models share pin-compatible packages. Selection should be based on target range and calibration flexibility.
5. Typical Application Scenarios
Application Field | Functional Role |
Smart Home & Consumer Devices | Embedded in air purifiers, thermostats, or smart speakers for real-time environment sensing |
HVAC Systems | Enables ventilation control based on CO₂ levels for energy-efficient air quality management |
Educational & Office Monitoring | Supports indoor air health assessment by evaluating ventilation efficiency |
Medical / Elderly Care Equipment | Enhances environmental control in chronic care and patient monitoring systems |
Wearable & Portable Devices | Integrates into mobile AQI meters for local CO₂ awareness |
6. Integration Guidelines
- Airflow Design: Ensure proper ventilation via PCB openings to avoid heat source interference.
- Thermal Layout: Avoid placing heat-generating components beneath the sensor to maintain local temperature stability.
- ASC Calibration: Suitable for typical indoor usage, minimizing maintenance via self-calibration without manual intervention.
- Software Support: Sensirion provides C-based drivers, integration guides, and sample code, compatible with platforms such as STM32 and Arduino.
7. Design Resources & Packaging Models
SCD40-D-R2 supports full design integration through schematic symbols, PCB footprint files, and 3D CAD models. Resources are available in SnapMagic and Ultra Librarian formats, compatible with Altium Designer, OrCAD, KiCad, and other mainstream EDA tools. WIN SOURCE platform enables fast access and download of all design assets for streamlined development.
The SCD40-D-R2 sensor integrates a compact form factor, low power consumption, and multi-parameter sensing for CO₂, temperature, and humidity. Its photoacoustic NDIR design and ASC auto-calibration make it ideal for space-constrained and power-sensitive embedded applications. With a solid understanding of the SCD4x series’ differences, developers can optimize component selection and system-level design strategies.
To explore more component specifications, packaging models, and inventory availability, please visit the official WIN SOURCE website.
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