Capture and respond to user inputs at different stages with SDS001 and ATmega1284

Double the signal, double the control: Microswitch innovation

Published Oct 17, 2023

Click board™

Tamper Click

Dev. board

EasyAVR v7

Compiler

NECTO Studio

MCU

ATmega1284

Learn how this versatile microswitch unlocks new potential for your projects, allowing you to design solutions that respond to both pressing and releasing actions

Hardware Overview

How does it work?

Tamper Click is based on the SDS001, low profile side-actuated detect switch from C&K. The switch itself acts as a push button and has 2 NO (Normally Open) terminals, which get shorted when the force is applied to the small piston-shaped button of the switch. These kinds of switches are usually mounted on the edge of the PCB so they can be easily reached by the elements that would apply a pressure to the switch. The applied pressure closes the circuit, connecting the VCC routed to the first pin of the

switch, with the INT pin on the mikroBUS™. The microcontroller is then able to detect a high logical level on the INT pin and the desired task can then be executed. The applied RC filter serves both as a debouncing circuitry and a pull-down for the terminal of the switch, preventing the floating state that way. The used switch itself is intended to operate with digital signal levels, thus its electrical characteristics are tailored for this purpose: low contact resistance of 100mΩ, relatively low contact ratings of 100mA at 12V and 50 000 switching

cycles before the failure. These attributes make it ideal for digital signal applications, specifically. This Click board™ can operate with either 3.3V or 5V logic voltage levels selected via the VCC SEL jumper. This way, both 3.3V and 5V capable MCUs can use the communication lines properly. Also, this Click board™ comes equipped with a library containing easy-to-use functions and an example code that can be used as a reference for further development.

Features overview

Development board

EasyAVR v7 is the seventh generation of AVR development boards specially designed for the needs of rapid development of embedded applications. It supports a wide range of 16-bit AVR microcontrollers from Microchip and has a broad set of unique functions, such as a powerful onboard mikroProg programmer and In-Circuit debugger over USB. The development board is well organized and designed so that the end-user has all the necessary elements in one place, such as switches, buttons, indicators, connectors, and others. With four different connectors for each port, EasyAVR v7 allows you to connect accessory boards, sensors, and custom electronics more

efficiently than ever. Each part of the EasyAVR v7 development board contains the components necessary for the most efficient operation of the same board. An integrated mikroProg, a fast USB 2.0 programmer with mikroICD hardware In-Circuit Debugger, offers many valuable programming/debugging options and seamless integration with the Mikroe software environment. Besides it also includes a clean and regulated power supply block for the development board. It can use a wide range of external power sources, including an external 12V power supply, 7-12V AC or 9-15V DC via DC connector/screw terminals, and a power source via the USB Type-B (USB-B)

connector. Communication options such as USB-UART and RS-232 are also included, alongside the well-established mikroBUS™ standard, three display options (7-segment, graphical, and character-based LCD), and several different DIP sockets which cover a wide range of 16-bit AVR MCUs. EasyAVR v7 is an integral part of the Mikroe ecosystem for rapid development. Natively supported by Mikroe software tools, it covers many aspects of prototyping and development thanks to a considerable number of different Click boards™ (over a thousand boards), the number of which is growing every day.

Microcontroller Overview

MCU Card / MCU

Architecture

AVR

MCU Memory (KB)

128

Silicon Vendor

Microchip

Pin count

RAM (Bytes)

16384

Used MCU Pins

mikroBUS™ mapper

RST

SCK

MISO

MOSI

Power Supply

3.3V

Ground

GND

PWM

Switch Detection

PD2

INT

SCL

SDA

Power Supply

Ground

GND

Take a closer look

Click board™ Schematic

Step by step

Project assembly

EasyAVR v7 front image hardware assembly

Start by selecting your development board and Click board™. Begin with the EasyAVR v7 as your development board.

NECTO Output Selection Step Image hardware assembly

In the advanced settings, pay special attention to the Redirect standard output field. By default, it is set to Application output as the method of displaying final results. To show results via a UART terminal, select the “UART” option in that field and click the “SAVE” button. You will be returned to the Compiler field, and now you can move on to the next step by pressing the “NEXT” button.

Buck 22 Click front image hardware assembly

EasyAVR v7 MB 1 - upright/background hardware assembly

NECTO Compiler Selection Step Image hardware assembly

Necto DIP image step 7 hardware assembly

EasyPIC PRO v7a Display Selection Necto Step hardware assembly

Track your results in real time

Application Output

1. Application Output - In Debug mode, the 'Application Output' window enables real-time data monitoring, offering direct insight into execution results. Ensure proper data display by configuring the environment correctly using the provided tutorial.

2. UART Terminal - Use the UART Terminal to monitor data transmission via a USB to UART converter, allowing direct communication between the Click board™ and your development system. Configure the baud rate and other serial settings according to your project's requirements to ensure proper functionality. For step-by-step setup instructions, refer to the provided tutorial.

3. Plot Output - The Plot feature offers a powerful way to visualize real-time sensor data, enabling trend analysis, debugging, and comparison of multiple data points. To set it up correctly, follow the provided tutorial, which includes a step-by-step example of using the Plot feature to display Click board™ readings. To use the Plot feature in your code, use the function: plot(*insert_graph_name*, variable_name);. This is a general format, and it is up to the user to replace 'insert_graph_name' with the actual graph name and 'variable_name' with the parameter to be displayed.

Software Support

Library Description

This library contains API for Tamper Click driver.

Key functions:

tamper_state - Function showes the state of the switch

Open Source

Code example

The complete application code and a ready-to-use project are available through the NECTO Studio Package Manager for direct installation in the NECTO Studio. The application code can also be found on the MIKROE GitHub account.

/*!
 * \file 
 * \brief Tamper Click example
 * 
 * # Description
 * Tamper click is equipped with side-actuated detect switch. The switch itself acts as 
 * a push button and has 2 Normally Open terminals, which get shorted when the force is applied. 
 * The applied pressure closes the circuit, connecting the VCC routed to the first pin 
 * of the switch with the INT pin on the mikroBUS. The microcontroller is then able to detect 
 * a high logical level on the INT pin and the desired task can then be executed.
 *
 * The demo application is composed of two sections :
 * 
 * ## Application Init 
 * Initialization driver enables GPIO and also starts write log.
 * 
 * ## Application Task  
 * This is an example which demonstrates the use of Tamper click board.
 * It detects whether the state of switch on Tamper click is changes to open or to closed.
 * Results are being sent to the Usart Terminal where you can keep track of their changes.
 * 
 * 
 * \author MikroE Team
 *
 */
// ------------------------------------------------------------------- INCLUDES

#include "board.h"
#include "log.h"
#include "tamper.h"

// ------------------------------------------------------------------ VARIABLES

static tamper_t tamper;
static log_t logger;

static uint8_t switch_state = 0;
static uint8_t switch_state_old = 1;

// ------------------------------------------------------ APPLICATION FUNCTIONS

void application_init ( void )
{
    log_cfg_t log_cfg;
    tamper_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.

    tamper_cfg_setup( &cfg );
    TAMPER_MAP_MIKROBUS( cfg, MIKROBUS_1 );
    tamper_init( &tamper, &cfg );
}

void application_task ( void )
{
    switch_state = tamper_state( &tamper );
    
    if ( switch_state == 1 && switch_state_old == 0 )
    {
        log_printf( &logger, "      Closed     \r\n" );
        log_printf( &logger, "- - - - - - - - -\r\n" );
        switch_state_old = 1;
    }

    if ( switch_state == 0 && switch_state_old == 1 )
    {
        log_printf( &logger, "       Open      \r\n" );
        log_printf( &logger, "- - - - - - - - -\r\n" );
        switch_state_old = 0;
    }
}

void main ( void )
{
    application_init( );

    for ( ; ; )
    {
        application_task( );
    }
}


// ------------------------------------------------------------------------ END