Stretch click

Stretch click is a mikroBUS™ add-on board with circuitry for measuring stretch forces with conductive rubber cords.

click Product page

Click library

• Author : MikroE Team
• Date : Jan 2020.
• Type : ADC type

Software Support

We provide a library for the Stretch 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 form compilers IDE(recommended way), or downloaded from our LibStock, or found on mikroE github account.

Library Description

This library contains API for Stretch Click driver.

Standard key functions :

• Config Object Initialization function.

  void stretch_cfg_setup ( stretch_cfg_t *cfg );

• Initialization function.

  STRETCH_RETVAL stretch_init ( stretch_t ctx, stretch_cfg_t cfg );

• Click Default Configuration function.

  void stretch_default_cfg ( stretch_t *ctx );

Example key functions :

• Config Object Initialization function.

  void stretch_cfg_setup ( stretch_cfg_t *cfg )

• Turn on the LED function

  void stretch_turn_on_led( stretch_t *ctx )

• Turn off the LED function

  void stretch_turn_off_led( stretch_t *ctx )

Examples Description

The application is for stretch measuring

The demo application is composed of two sections :

Application Init

Initialization driver enables GPIO and ADC, turn off the LED and starts write log.

void application_init ( void )
{
    log_cfg_t log_cfg;
    stretch_cfg_t cfg;

    /** 
     * Logger initialization.
     * Default baud rate: 115200
     * Default log level: LOG_LEVEL_DEBUG
     * @note If USB_UART_RX and USB_UART_TX 
     * are defined as HAL_PIN_NC, you will 
     * need to define them manually for log to work. 
     * See @b LOG_MAP_USB_UART macro definition for detailed explanation.
     */
    LOG_MAP_USB_UART( log_cfg );
    log_init( &logger, &log_cfg );
    log_info( &logger, "---- Application Init ----" );

    //  Click initialization.

    stretch_cfg_setup( &cfg );
    STRETCH_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    stretch_init( &stretch, &cfg );

    Delay_100ms();

    log_printf( &logger, "------------------- \r\n" );
    log_printf( &logger, "  Stretch  click  "  );
    log_printf( &logger, "-------------------\r\n" );

    stretch_turn_off_led( &stretch );
    Delay_100ms( );

    log_printf( &logger, " ADC Initializated " );
    log_printf( &logger, "-------------------" );
}

Application Task

This is a example which demonstrates the use of Stretch Click board. Stretch Click reads and display ADC value.

void application_task ( void )
{
    stretch_data_t tmp;

    //  Task implementation.

    tmp = stretch_generic_read ( &stretch );
    log_printf( &logger, "** ADC value : [DEC]- %d, [HEX]- 0x%x \r\n", tmp, tmp );
    Delay_ms ( 1000 );

    Delay_100ms( );

    if ( tmp < 500 )
    {
        stretch_turn_on_led( &stretch );
    }

    else
    {
        stretch_turn_off_led( &stretch );
    }

    log_printf( &logger, " Resistance : %d \r\n", tmp );
    log_printf( &logger, "-------------------" );
    Delay_1sec( );
} 

The full application code, and ready to use projects can be installed directly form compilers IDE(recommneded) or found on LibStock page or mikroE GitHub accaunt.

Other mikroE Libraries used in the example:

• MikroSDK.Board
• MikroSDK.Log
• Click.Stretch

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