Single Double Click and Long Press Detection

Solving Approach

How do you plan to solve it?

 
1. Solving Approach
To solve this problem, we will build a circuit with a push-button switch connected to a microcontroller and write a program to interpret different press durations.

Hardware Setup: We will connect a push-button to a digital pin on an Arduino Uno. To ensure the pin reads a consistent value when the button is not pressed, we will use the Arduino's internal pull-up resistor. This is a simple and effective method that eliminates the need for an external resistor. When the button is not pressed, the internal resistor pulls the pin's voltage high (to 5V). When the button is pressed, it connects the pin to the ground (0V), effectively pulling the pin's voltage low.

Software Logic: The core of the solution lies in the code, which will use timing to differentiate between a single click, a double click, and a long press. We will use the millis() function to track time, which is a non-blocking alternative to delay(), allowing for more responsive code. A simple state machine will be used to track button events:

Debouncing: When a button press is detecated, we'll wait for a short period (e.g., 50ms) to ensure the signal is stable and to filter out electrical noise from the mechanical press.

Single Click/Double Click: We'll start a timer when a press is released. If another press occurs within a short, predefined time window (e.g., 500ms), it's a double click. If the button is not pressed again within that window, it's a single click.

Long Press: When a button press is detected, we'll record the start time. If the button remains pressed for a longer, predefined duration (e.g., 1000ms), it's a long press.

Output: The code will send a message to the Serial Monitor via the Serial.println() function, indicating the type of button press that was detected.
 

Code

/*Paste your code here*/

// Define the button pin
const int buttonPin = 2;

// Timing constants (in milliseconds)
const long longPressTime = 1000;  // 1 second
const long doubleClickTime = 500; // 0.5 seconds
const int debounceDelay = 50;     // 50 milliseconds

// State variables
int lastButtonState = HIGH;      // the previous button state
unsigned long pressStartTime = 0;   // the time the button was pressed
unsigned long lastClickTime = 0;    // the time of the last click
int clickCount = 0;              // number of clicks detected

void setup() {
  // Initialize the button pin with an internal pull-up resistor
  pinMode(buttonPin, INPUT_PULLUP);
  // Start serial communication at 115200 baud
  Serial.begin(115200);
}

void loop() {
  // Read the current state of the button
  int buttonState = digitalRead(buttonPin);

  // Debouncing
  if (buttonState != lastButtonState) {
    delay(debounceDelay);
    buttonState = digitalRead(buttonPin);
  }

  // Check for button press
  if (buttonState == LOW && lastButtonState == HIGH) {
    pressStartTime = millis(); // Record the start time of the press
  }

  // Check for button release
  if (buttonState == HIGH && lastButtonState == LOW) {
    unsigned long pressDuration = millis() - pressStartTime;

    // Check for a long press
    if (pressDuration >= longPressTime) {
      Serial.println("Long press detected");
      clickCount = 0; // Reset click count after a long press
      lastClickTime = 0;
    } else {
      // It's a click, either single or double
      if (millis() - lastClickTime <= doubleClickTime) {
        // This is a double click
        clickCount++;
        if (clickCount >= 2) {
          Serial.println("Double click detected");
          clickCount = 0; // Reset for next sequence
          lastClickTime = 0;
        }
      } else {
        // This is the first click in a potential double-click sequence
        clickCount = 1;
        lastClickTime = millis();
      }
    }
  }

  // Handle single click if the double-click timeout has passed
  if (clickCount == 1 && millis() - lastClickTime > doubleClickTime) {
    Serial.println("Single click detected");
    clickCount = 0;
    lastClickTime = 0;
  }

  // Save the current state for the next loop iteration
  lastButtonState = buttonState;
}

Output

Video

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