Button_SL Library

The Button_SL library consists of two classes (Button and ButtonSL) for querying buttons.

Button is a class for debouncing button queries. The debounce time can be specified. The object returns a true if a button press was detected, otherwise a false is returned. The debounce time can also be used to specify a minimum press length (e.g. a button must be pressed for at least 0.5 seconds).

ButtonSL is extended so that a distinction can be made between a short and long button press. A time (in ms) can be specified after which a button press is considered "long". Correspondingly, the tick() method returns the status notPressed, shortPressed or longPressed.

Examples

A button object for PIN2. The button is connected via VCC, with a pull-down resistor on the Arduino pin. Therefore the active state is HIGH: Button btn{2,HIGH};

Initialize the object and set the debounce time to 20ms (default is 30ms):

#include <Button_SL.hpp>

using namespace Btn;
Button btn{2,HIGH};

// in void setup()
void setup() {
  btn.begin();
  btn.setDebounceTime_ms(20);
}

// in void loop()
void loop() {
  if (btn.tick() == true){
    Serial.println("Button was pressed");
  }
}

Create a button object for PIN2 that determines the length of a button press. The button is connected with a pulldown resistor. Therefore the active state is HIGH:
ButtonSL btnSL{2,1500,HIGH};

btnSL will return Buttonstate::shortPressed for a press duration < 1500ms. For >= 1500ms Buttonstate::longPressed will be returned. The time is stored in an unsigned int attribute and must not exceed 65535 ms.

#include <Button_SL.hpp>

using namespace Btn;
ButtonSL btnSL{2,1500,HIGH};

// in void setup()
void setup() {
  btnSL.begin();
}

// in void loop()
void loop() {
  switch (btnSL.tick()) {
    case ButtonState::shortPressed: 
      Serial.print(". "); Serial.print(btnb.getDuration_ms()); Serial.println(" ms"); 
      break;
    case ButtonState::longPressed: 
      Serial.print("- "); Serial.print(btnb.getDuration_ms()); Serial.println(" ms"); 
      break;
    default: 
      break;  
  }
}

If the button is connected to GND and the internal pullup resistor of the microcontroller is to be used, the button objects can be created as follows:

Button btn{2};              // Use pin 2, INPUT_PULLUP
ButtonSL btnSL{3,1500};     // Use pin 3, 1500ms for long, INPUT_PULLUP
ButtonSL btnSL2{4};         // Use pin 4, 1000ms for long, INPUT_PULLUP

If the active status of the connected buttons is HIGH, the objects can be created in the following way:

Button btn{2,HIGH}    
// No Pullup, the default value does not apply here! All three parameters must be specified.
ButtonSL btn3{5,1000,HIGH}; // Use pin 5, 1000ms for long, INPUT

INPUT_PULLUP is the default value with which the button objects are initialized. Therefore, no specification must be made here. BUT, if ButtonSL objects with active state HIGH are used, all three parameters must be specified when creating the object.

You can test this library with the online simulator wokwi:: Button Example

Default values

• Active status for a pushbutton press: INPUT_PULLUP
• Time limit for the distinction between short and long button presses: 1000ms (max. 65535 ms).
• Debounce time: 30ms (max. 65535 ms).
• For ButtonSL releaseOff()

Methods

The methods of the objects are named so that their function should be self-explanatory:

Button Methods:

Method	Class	Action
begin()	Button/SL	Initialize Pins
tick()	Button/SL	Query the pin status
setDebounceTime_ms(uint16_t)	Button/SL	Set Debouncetime in ms
releaseOn()	ButtonSL	Automatic release of the push-button after the time period for a long push-button action has elapsed.
releaseOff() (default)	ButtonSL	No automatic release of the push-button
setTimeThreshold_ms(uint16_t)	ButtonSL	Set the time threshold from which a button press is recognized as long.
getDuration_ms()	ButtonSL	Delivers the time in ms that the pushbutton was pressed