News — K30

CO2 Sensors and Raspberry Pi

Our engineers have created application notes to connect two of CO2Meter’s most popular CO2 sensors with the popular Raspberry Pi. The Raspberry Pi is a credit-card-sized computer that plugs into a monitor and keyboard. It makes it easy for hobbyists to create projects for a very low cost. COZIR CO2 Sensor This app note AN-127 explains how to connect the Raspberry Pi 3 with the COZIR CO2 sensor via UART. Includes step by step instructions. AN127 Instructions here (pdf). AN127 project source code here (zip).   K-30 CO2 Sensor This app note AN-137 explains how to connect the Raspberry Pi 3...

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Arduino CO2 Sensor Application Notes Update

Our engineering team has rewritten the application notes to connect the Arduino Uno, Mega or Mega2560 microcontrollers with two of our most popular CO2 sensors. AN-126 – Arduino UART Interface to K-30 Sensor. This app note and included source code (zip) gives you step by step instructions for connecting SenseAir’s K-30 CO2 sensor using an industry‐standard UART TXD‐RXD connection. Wiring diagrams are included. AN-128 – Arduino UART interface to COZIR Sensor. This app note and included source code (zip) gives you step by step instructions for connecting the GSS COZIR sensor using an industry‐standard UART TXD‐RXD connection. Wiring diagrams are...

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Altitude Compensation for CO2 Sensor Modules

A customer called recently and said we had sold him a defective sensor module. He had calibrated it precisely at 0.0ppm (zero parts-per-million), took it outside, and the sensor read 335ppm. “Where do you live?” we asked. “Colorado,” he replied. It took a few minutes to explain, but in the end the customer understood that altitude makes a difference when you are measuring CO2 levels. CO2 sensor modules are calibrated at sea level, and are not designed to automatically compensate for changes to CO2 at higher altitudes. When you think about altitude, it helps to imagine a vertical column of...

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Senseair CO2 Sensor Pressure Dependence

All infrared (NDIR) CO2 sensors have a dependence on pressure. This is because of the physics principle used to measure CO2 concentration. The NDIR type of sensor measures the IR radiation absorbed by CO2 molecules, which corresponds to the mole concentration. When pressure increases, the number of molecules in a given volume also increases linearly. Conversely, when pressure decreases (higher altitudes, for example) the number of molecules decrease. This app note includes both general information about Senseair sensors and pressure, as well as the equation for computing true CO2 level readings at various pressures useful for any NDIR CO2 sensor....

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Arduino Code for K-30 CO2 Sensor Works for S8 Sensor Too

Many clients use our Arduino UART examples and Arduino source code to connect the popular SenseAir K-30 sensor to Arduino boards. However, these examples were all created before the SenseAir S8 CO2 Sensor was developed. So we were surprised when a client recently wrote us: "To my surprise, the script you give for the K30 sensor works out of the box with the S8! Why don't you mention it in the app note? Had I known that from the start, I wouldn't have bothered you about which sensor to buy..." Frankly, we were a bit sheepish. In all the projects...

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