Alcohol 2 Click

The AFE IC provides a unified platform for many types of electrochemical sensors and as such, it packs a range of different features which simplify the use of various electrochemical sensors. The AFE IC supports gas sensitivity in a range from 0.5 nA/ppm to 9500 nA/ppm. Equipped with the SPEC ethanol sensor with resolution of 5ppb, the Click board™ can be used for various alcohol breathalyzer applications, alcohol breath testers, atmospheric ethanol presence detection applications, and similar.

How does it work?

SPEC Sensor™ are amperometric gas sensors, electrochemical sensors which generate a current proportional to the volumetric fraction of the gas. This current is converted and transformed into the voltage by the analog front-end IC (AFE), so it can be sampled by the MCU, or converted with the external A/D converting circuits. The sensor used on this board is the 3SP-Ethanol-1000 from SPEC Sensors, which can sense ethanol concentration up to 1000ppm. The sensor has a very short response time, however the longer it is exposed to a particular gas, the more accurate data it can provide. This is especially true when calibration is performed. It should be noted that the sensor has a very high sensitivity to small particles of dust, condensed water, and other impurities, which might prevent gas to reach the sensor. It is advised to protect the sensor when used in critical applications. In ideal conditions, the lifetime of this sensor is indefinite, but in the real-life applications, the expected operating life is more than 5 years (10 years at 23 ± 3 ˚C; 40 ± 10 %RH).

Specifications

Pinout diagram

This table shows how the pinout on Alcohol 2 click corresponds to the pinout on the mikroBUS™ socket (the latter shown in the two middle columns).

Notes	Pin					Pin	Notes
Analog OUT	AN	1	AN	PWM	16	PWM
I2C Enable	RST	2	RST	INT	15	FG
	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

Onboard jumpers and settings

Alcohol 2 click electrical specifications

Software support

We provide a demo application for Alcohol 2 click on our Libstock page, as well as a demo application (example), developed using MikroElektronika compilers. The demo can run on all the main MikroElektronika development boards.

Library Description

The library initializes and defines the I2C bus driver and drivers that offer a choice for writing data in a register. The library includes the function for reading the Alcohol data.

Key functions :

uint16_t alcohol2_readAlcohol() - Function for reading the Alcohol data

void alcohol2_writeByte( uint8_t reg, uint8_t _data ) - The function writes one byte to the register.

Example description

The application is composed of three sections:

• System Initialization - Initializes I2C bus and set AN pin as INPUT and RST pin as OUTPUT.
• Application Initialization - Initializes I2C driver and device configuration.
• Application Task - (code snippet) - Gets Alcohol (C2H5OH) data and logs data to USBUART every 500ms.

void applicationTask()
{
 Alcohol_Value = alcohol2_readAlcohol();
 FloatToStr( Alcohol_Value, demoText );
 mikrobus_logWrite( "Alcohol value : ", _LOG_TEXT );
 mikrobus_logWrite( demoText, _LOG_LINE );
 Delay_ms( 500 );
}

The full application code and ready to use projects can be found on our LibStock page.

mikroE Libraries used in the example:

• I2C
• Conversions

Additional notes and information

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. The terminal available in all MikroElektronika compilers, or any other terminal application of your choice, can be used to read the message.

mikroSDK

This 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.

For more information about mikroSDK, visit the official page.