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/** @file
* Definition of the SWitchControl class. This file contains the definition of
* the class used to control, and detect button presses from, an illuminated
* push-button switch.
*
* @author Chris Page <chris@starforge.co.uk>
* @copyright MIT License, 2020 Chris Page
*/
/* The MIT License (MIT)
*
* Copyright (c) 2020 Chris Page
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#ifndef SwitchControl_H
#define SwitchControl_H
#include <Arduino.h>
/** A class to interact with a SPST momentary illuminated switch. This class
* provides features to turn on or off the LED illumination in the switch,
* and software debounce and press/longpress detection for button pushes.
* This class requires one digital input pin and one digital output pin per
* instance, and allows the debounce and longpress timers to be configured
* during creation.
*/
class SwitchControl
{
public:
/** The possible kinds of events that may be reported by update()
*/
enum Event {
EVENT_NONE, //!< Nothing happened. Nothing to see here, move along.
EVENT_PRESSED, //!< The switch was pressed.
EVENT_LONGPRESS, //!< The switch had been held long enough to trigger a longpress.
EVENT_RELEASED //!< The switch was released.
};
/** Create a new SwitchControl object for interacting with an illuminated
* push-button switch.
*
* @param switch_pin The digital pin the switch is connected to. This should
* go high when the switch is pressed, and low when not.
* @param led_pin The digital pin the LED is connected to. The LED will be
* initialised to be off during setup.
* @param debounce_time Time in milliseconds to delay swith state change by to
* allow for switch bounce to be ignored. Increase this if
* spurious press and release events are generated.
* @param longpress_time If the switch is held pressed for this amount of time
* in milliseconds a 'long press' event will be generated.
*/
SwitchControl(uint8_t switch_pin, uint8_t led_pin, unsigned long debounce_time = 50, unsigned long longpress_time = 3000) :
switch_pin(switch_pin), led_pin(led_pin),
switch_state(LOW),in_longpress(false),last_press(0),last_release(0),
last_state(LOW),last_debounce(0),
debounce_time(debounce_time), longpress_time(longpress_time)
{ /* fnord */ }
/* ------------------------------------------------------------------------
* Setup and main loop interaction
*/
/** Initialise the IO for the SWitchControl object.
* This sets the configuration of the IO pins for the switch and LED control,
* it should be called once from the global setup() function.
*/
void setup();
/** Check the status of the switch, and determine whether any events
* should be triggered as a result of its state. This performs switch
* debouncing to try to avoid spurious events, and can detect when the switch
* has been held down to trigger a long press event.
*
* @return A value indicating whether an event happened during this
* update, and if so what kind of event.
*/
Event update();
/* ------------------------------------------------------------------------
* Control functions
*/
/** Set the illumination LED in the switch to either on or off.
*
* @param state Set to `true` to turn the LED on, `false` to turn it off.
*/
void set_led_state(bool state);
/* ------------------------------------------------------------------------
* State lookup
*/
/** Determine whether the switch is currently pressed.
*
* @return `true` if the switch is currently pressed, `false` if it is not.
*/
bool is_pressed()
{
return (switch_state == HIGH);
}
/** Obtain the time since the last press event happened. Note that this
* will return a value since the press event even if the switch has been
* released.
*
* @return The time in milliseconds since the last press event.
*/
unsigned long time_since_pressed()
{
return (millis() - last_press);
}
/** Obtain the time since the last release event happened. This will return
* a value even if the switch has been pressed.
*
* @return The time in milliseconds since the last release event.
*/
unsigned long time_since_released()
{
return (millis() - last_release);
}
private:
// Digital pin configuration
uint8_t switch_pin; //!< The digital pin the switch connected to
uint8_t led_pin; //!< The digital pin the indicator LED connected to
// Button state information
uint8_t switch_state; //!< The current switch state
bool in_longpress; //!< Are we in a long press state?
unsigned long last_press; //!< The time in millis since last reset that the last press happened (after debounce)
unsigned long last_release; //!< The time in millis since last reset that the last release happened (after debounce)
// Timing control
unsigned long debounce_time; //!< Time to delay during debounce, in milliseconds.
unsigned long longpress_time; //!< How long the switch must be held to trigger a 'longpress' event
// State variables needed to persist data over update()s
uint8_t last_state; //!< Previous reading from the switch
unsigned long last_debounce; //!< The time at which the last state change occurred during debounce
};
#endif