Mikroelektronika d.o.o.
Luftqualität 4 Click Board
Luftqualität 4 Click Board
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Das Air Quality 4 Click Board™ ist ein fortschrittliches Luftqualitätssensorgerät, das mehrere Metalloxid-Sensorelemente auf einem Chip kombiniert, um detaillierte Informationen zu den Luftqualitätsparametern bereitzustellen. Dieses Click Board™ kann TVOC-Werte sowie die CO2-Äquivalentkonzentrationswerte in Innenräumen ausgeben.
Neben diesen kompensierten Attributen kann das Air Quality 4 Click Board™ auch Rohwerte von H2 und Ethanol in der Luft ausgeben, die zur Berechnung von Gaskonzentrationen im Verhältnis zu einer Referenzkonzentration verwendet werden können.
The Air Quality 4 Click Board™ is an advanced air quality sensing device that combines multiple metal-oxide sensing elements on a chip to provide detailed information of the air quality parameters. This Click Board™ can output a TVOC value readings as well as the CO2 equivalent concentration readings in an indoor environment. Besides these compensated attributes, the Click Board™ can also output raw values of H2 and Ethanol in the air, that can be used to calculate gas concentrations, relative to a reference concentration.
The sensor used on the Air Quality 4 Click Board™ is actually a complete system of sensors on a chip, featuring I2C interface, a temperature controlled micro hotplate, and two compensated and processed indoor air quality signals. It is produced using the proprietary CMOSens technology, which provides very detailed information and robustness against air contamination. These attributes make Air quality 4 Click Board™ a perfect solution for various air conditioning systems, ventilation systems and other IoT applications where accurate, detailed and reliable air quality readings are required.
How Does The Air Quality 4 Click Board™ Work?
The sensor IC used on the Air Quality 4 Click Board™, is the SGP30 from Sensirion, a multi-pixel gas sensor for indoor applications. This sensor is actually a system of several metal-oxide sensing elements on a chip (pixels), used to measure and process readings of various gasses in the air and output them in a form of two complementary air quality readings - Total Volatile Organic Compounds (TVOC) [ppb] and CO2 equivalent signal [ppm].The traditional metal-oxide (MOX) sensors suffer from sensitivity and responsiveness degradation, after being exposed to siloxanes over time. Siloxanes are specific compounds commonly found in the air, which negatively affect the MOX sensors. To overcome this problem, the SGP30 sensors are made by utilising the advanced MOXSens Technology, which provides these sensors with the unmatched robustness against siloxanes contamination. This results with unprecedented long-term stability and accuracy.
The SGP30 uses a dynamic baseline compensation algorithm and calibration parameters, to provide accurate readings of TVOC and CO2eq properties. These baseline values of the compensation algorithm can be stored externally and read back into the device with the appropriate I2C commands and can be used in an event of power down or restart. For the first 15 seconds after the I2C initialization command, the sensor is in an initialization phase of collecting sensor measurements and baseline compensation data and will return fixed values of 400 ppm CO2eq and 0 ppb TVOC, when measurement command is attempted.
The device also allows air humidity corrections over the results for both the compensated and raw values. However, an absolute humidity sensor should be used for obtaining the humidity reading. Readings from SHT Click Board™ or any other similar humidity measuring device can be used for this purpose. The appropriate I2C command will store the value into the on-chip memory and perform the corrections, accordingly.
There are additional components on Air quality 4 Click Board™, that are used to provide necessary voltage levels for the SGP30 sensor IC. This sensor uses not so common voltage level of 1.8V, so to provide a proper communication with 3.3V and 5V capable MCUs, a small LDO voltage regulator has to be used, along with the level shifter, which provides required logic voltage levels. The SPX3819M5, a small 500mA LDO voltage regulator is used to provide the power supply of 1.8V for the SGP30. For the level shifting, the PCA9306 dual bidirectional I2C bus and SMBus voltage level shifter is used. This level shifter IC allows shifting (converting) the I2C signal levels to the voltage level selected by the VCC SEL on-board SMD jumper. This allows both 3.3V and 5V capable MCUs to be interfaced with the Air quality 4 Click Board™.
More detailed information about all the available I2C commands can be found in the SGP30 datasheet. However, all the functions and commands necessary to perform air quality readings, as well as functions used to calculate H2 and Ethanol concentration levels, are contained within the Air Quality 4 Click Board™ libraries, provided with this Click Board™. Their usage is demonstrated in the included example application, which can be used as a reference for a custom application design.
SPECIFICATIONS
| Type | Air Quality, Gas |
| Applications | A perfect solution for various air conditioning systems, ventilation systems and other IoT applications where accurate, detailed and reliable air quality readings are required. |
| On-board modules | SGP30 from Sensirion, a multi-pixel gas sensor, SPX3819M5, a small 500mA LDO voltage regulator from EXAR, PCA9306 dual bidirectional I2C bus and SMBus voltage level shifter from Texas Instruments |
| Key Features | This device combines multiple metal-oxide sensing elements on a chip to provide detailed information of the air quality parameters. SGP30 sensor is manufactured with the proprietary MOXSens® Technology that ensures unique long-term stability and accuracy. |
| Interface | I2C |
| Compatibility | mikroBUS |
| Click board size | L (57.15 x 25.4 mm) |
| Input Voltage | 3.3V or 5V |
PINOUT DIAGRAM
This table shows how the pinout on the Air Quality 4 Click Board™ corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).
| Notes | Pin |  |
Pin | Notes | |||
|---|---|---|---|---|---|---|---|
| NC | 1 | AN | PWM | 16 | NC | ||
| NC | 2 | RST | INT | 15 | NC | ||
| NC | 3 | CS | RX | 14 | NC | ||
| NC | 4 | SCK | TX | 13 | NC | ||
| NC | 5 | MISO | SCL | 12 | SCL | I2C Clock | |
| NC | 6 | MOSI | SDA | 11 | SDA | I2C Data | |
| Power supply | +3.3V | 7 | 3.3V | 5V | 10 | +5V | Power supply |
| Ground | GND | 8 | GND | GND | 9 | GND | Ground |
AIR QUALITY 4 CLICK ELECTRICAL SPECIFICATIONS
| Description | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Measurement range of H2 and Ethanol | 0 | 1000 | ppm | |
| Sampling frequency of H2 and Ethanol | 40 | Hz | ||
| Measurement range of TVOC | 0 | 60000 | ppb | |
| Measurement range of CO2eq | 400 | 60000 | ppm | |
| Sampling frequency of TVOC and CO2eq | 1 | Hz | ||
| I2C clock frequency | 0 | 400 | kHz |
ONBOARD SETTINGS AND INDICATORS
| Label | Name | Default | Description |
|---|---|---|---|
| LD1 | PWR | - | Power LED indicator |
| JP1 | VCC SEL | Left | Voltage level selection, left position 3.3V, right 5V |
Software Support
We provide a library for the Air Quality 4 Click Board™ on our LibStock page, as well as a demo application (example), developed using MikroElektronika compilers and mikroSDK. The provided click library is mikroSDK standard compliant. The demo application can run on all the main MikroElektronika development boards.
Library Description
Initializes and defines I2C bus driver and driver functions which perform measurements of H2, TVOC, CO2 and EthOH (Ethanol) concentration in the air. Check the documentation for more details.
Key functions
void air_quality4_measureQuality(uint8_t *readAir) - The function writes 6 bytes CO2 data (2 bytes) and TVOC data (2 bytes) with CRC data for each of them to a buffer, pointed by the function parameter.
void air_quality4_getCO2AndTVOC(uint16_t *value) - The function writes 2 bytes CO2 data and 2 bytes TVOC data without CRC data to a buffer, pointed by the function parameter.
void air_quality4_measureSignal(uint8_t *readAir) - The function writes 6 bytes H2 data (2 bytes) and EthOH - Ethanol data (2 bytes) with CRC data for each of them to a buffer, pointed by the function parameter.
void air_quality4_getH2AndEthOH(uint16_t *value) - The function writes 2 bytes of H2 data and 2 bytes of EthOH data without CRC data to a buffer, pointed by the function parameter.
Example Description
- System Initialization - Initializes peripherals and pins. Application Initialization - Initializes click driver and gets ID data.
- Application Task - Performs measurements of air concentration for H2, EthOH(Ethanol), CO2 and TVOC data. Results of the measurement are output to the UART.
void applicationTask()
{
air_quality4_getH2AndEthOH(&data_buffer[0]);
IntToStr(data_buffer[0], text);
mikrobus_logWrite("H2 value is: ", _LOG_TEXT);
mikrobus_logWrite(text, _LOG_LINE);
IntToStr(data_buffer[1], text);
mikrobus_logWrite("EthOH value is: ", _LOG_TEXT);
mikrobus_logWrite(text, _LOG_LINE);
air_quality4_setBaseline();
air_quality4_getCO2AndTVOC(&data_buffer[0]);
IntToStr(data_buffer[0], text);
mikrobus_logWrite("CO2 value is: ", _LOG_TEXT);
mikrobus_logWrite(text, _LOG_LINE);
IntToStr(data_buffer[1], text);
mikrobus_logWrite("TVOC value is: ", _LOG_TEXT);
mikrobus_logWrite(text, _LOG_LINE);
Delay_ms(1000);
}
The full application code, and ready to use projects can be found on our LibStock page.
Additional Notes and Information
Depending on the development board you are using, you may need a USB UART click, USB UART 2 click or RS232 click to connect to your PC, for development systems with no UART to USB interface available on the board. The terminal available in all MikroElektronika compilers, or any other terminal application of your choice, can be used to read the message.
MIKROSDK
The Air Quality 4 Click Board™ is supported with mikroSDK - MikroElektronika Software Development Kit. To ensure proper operation of mikroSDK compliant click board demo applications, mikroSDK should be downloaded from the LibStock and installed for the compiler you are using.
Luftqualität 4 Click Board
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