Pollution Click

How does it work?

Pollution Click is based on the WSP2110, a VOC gas sensor from Winsen. The MQ-135 can detect the presence and concentration of toxic gases in the air, such as toluene, benzene, methanal, and alcohol. It consists of a heater and metal oxide semiconductor material on the ceramic substrate of subminiature Al2O3, which are fetched out by electrode down-lead and encapsulated in a metal socket and cap. Besides its high sensitivity, the WSP2110 is also characterized by a detection range from 1 to 50 ppm for toluene, benzene, methanal, and alcohol.

The WSP2110 provides an analog representation of polluted concentration in the air sent directly to an analog pin of the mikroBUS™ socket labeled OUT. The analog output voltage the sensor provides varies in proportion to the toxic gas concentration; the higher the toxic gas concentration in the air, the higher the output voltage. Also, this Click board™ has a built-in potentiometer that allows users to adjust the load resistance of the MQ-135 circuit for optimum performance. The ENA pin can be used to enable the gas sensor.

This Click board™ can be operated only with a 5V logic voltage level. The board must perform appropriate logic voltage level conversion before using MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.

Specifications

Pinout diagram

This table shows how the pinout on Pollution Click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
Analog Signal	OUT	1	AN	PWM	16	NC
Enable Sensor	ENA	2	RST	INT	15	NC
	NC	3	CS	RX	14	NC
	NC	4	SCK	TX	13	NC
	NC	5	MISO	SCL	12	NC
	NC	6	MOSI	SDA	11	NC
	NC	7	3.3V	5V	10	5V	Power Supply
Ground	GND	8	GND	GND	9	GND	Ground

Onboard settings and indicators

Pollution Click electrical specifications

Software Support

We provide a library for the Pollution Click as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.

Package can be downloaded/installed directly from NECTO Studio Package Manager (recommended), downloaded from our LibStock™ or found on Mikroe github account.

Library Description

This library contains API for Pollution Click driver.

Key functions

• This function read ADC data.

• This function gets load voltage from read ADC value.

• This function gets the corrected resistance of the sensor.

Example Description

Example code reads ADC value and measures quantity of organic gases in the air.

 void application_task ( void ) 
 { 
     pollution_data_t tmp; 

     tmp = pollution_generic_read( &pollution ); 
     log_printf( &logger, " ADC value : %d ppmrnn", tmp ); 
     Delay_ms( 1000 ); 

     value_volt = pollution_measure_load_voltage( &pollution, tmp ); 
     log_printf( &logger, " Load voltage : %0.2f Vrnn", value_volt ); 
     Delay_ms( 1000 ); 

     value_res = pollution_get_corrected_resistance( &pollution, tmp ); 
     log_printf( &logger, " Corrected resistance : %0.2f kOhmrnn", value_res ); 
     log_printf( &logger, "---------------------------------------------rnn" ); 
     Delay_ms( 1000 ); 
 }

The full application code, and ready to use projects can be installed directly from NECTO Studio Package Manager (recommended), downloaded from our LibStock™ or found on Mikroe github account.

Other Mikroe Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.Pollution

Additional notes and informations

Depending on the development board you are using, you may need 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. UART terminal is available in all MIKROE compilers.

mikroSDK

This Click board™ is supported with mikroSDK – MIKROE 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.

For more information about mikroSDK, visit the official page.