SCD40 Miniature NDIR CO2 Sensor Module - I2C Breakout Board (400-2000ppm)

Specifications

• Sensor Core: SCD40 (Photoacoustic NDIR).

• Target Gas: Carbon Dioxide (CO2).

• Measurement Range: 400 ppm – 2,000 ppm.

• Accuracy: ±(50 ppm + 5% of reading).

• Secondary Measurements: Temperature (-10°C to 60°C) & Humidity (0-100% RH).

• Interface: I2C (Address 0x62).

• Supply Voltage: 3.3V to 5V (Module includes regulation).

• Form Factor: Purple Breakout PCB with 4-pin Header (Unsoldered).

Key Applications & Projects

• Smart Thermostats: Adjust ventilation based on actual occupancy (CO2 levels rise when people are in the room).

• COVID/Health Monitors: High CO2 indicates poor ventilation and increased viral transmission risk.

• Plant Growth: Monitor CO2 in mini-greenhouses or terrariums (though max 2000ppm is the limit for this model).

• Portable Air Quality Meter: Tiny size and low power make it perfect for battery-operated wearables.

Project Evolution

• The Bottleneck: Traditional NDIR sensors (like MH-Z19) are too big for small cases and require manual calibration often.

• The Upgrade: The SCD40 is 5x smaller. It also features ASC (Automatic Self-Calibration), which keeps it accurate over the years without you needing to intervene.

• Effort Level: Intermediate. Requires soldering the 4-pin header (included) and installing the Sensirion I2C SCD4x library.

Virtual Technician & Setup Guide

• Header Pins: The module comes with a 4-pin header strip loose in the bag. You need to solder it to the board yourself.

• Placement: Do not cover the small white filter on top of the silver can! This is where the air enters.

• Vibration: Photoacoustic technology uses sound waves. Avoid mounting the sensor directly next to a vibrating motor or loud buzzer, as it might interfere with readings.

• Voltage: The module is 5V tolerant, but 3.3V is recommended for ESP32 projects.

Accessories & Compatibility

• Included: 1x SCD40 Sensor Module, 1x 4-Pin Header Strip (Straight).

• Compatible: Arduino, ESP32, Raspberry Pi, STM32 (via I2C).

• Library: "Sensirion I2C SCD4x" (Available in Arduino Library Manager).

Helpful Tutorials & Resources

• SCD40 CO2 Sensor_Datasheet

• SCD40 Arduino Library & Guide
  

Frequently Asked Questions (Technical SEO)

• What is the difference between SCD40 and SCD41? The SCD40 is the standard version with a range of 400-2000 ppm. The SCD41 is the high-performance version with a range up to 5000 ppm and supports "Low Power Single Shot" mode. This product is the SCD40.
• Is this the bare chip or a module? This is the Breakout Module. The tiny sensor is already mounted on a PCB with the necessary capacitors and resistors, making it easy to wire up.
• How does Photoacoustic NDIR work? It pulses infrared light into the gas. CO2 molecules absorb this light and vibrate, creating a tiny sound wave (pressure change) that a microscopic microphone detects. It's like NDIR, but using sound instead of light detectors.
• Does it need calibration? It has Automatic Self-Calibration (ASC) enabled by default. It assumes the lowest reading over a 7-day period is fresh air (400 ppm). You can also force calibrate it manually if needed.
• Is it compatible with 5V Arduino? Yes, the module typically includes circuitry to handle 3.3V to 5V power, but the I2C lines are best used with 3.3V logic or a level shifter for long-term safety.
• Can I use it outdoors? It is designed for indoor use. Outdoor humidity or rain can damage the sensitive microphone and filter.
• What is the I2C address? The fixed I2C address is 0x62.
• Does it measure temperature and humidity too? Yes! It has a built-in SHT4x-class sensor that provides very accurate temperature and humidity readings along with CO2.
• Why is it clicking? You can't hear it, but the sensor pulses light internally. If you have a very sensitive power supply, you might see tiny ripples in voltage during measurement.
• How fast is the reading? By default, it updates every 5 seconds.