How to Use Rotary encoder with button: Examples, Pinouts, and Specs

A rotary encoder with an integrated push button is a versatile electronic component used to convert rotational position into an analog or digital signal. This component is widely used in various applications, including:

• User Interfaces: For navigating menus and adjusting settings in devices like audio equipment, industrial controls, and home appliances.
• Robotics: For precise control of motor positions and angles.
• Measurement Systems: For tracking rotational position and speed in machinery.
• Gaming: As input devices in custom game controllers.

1. Power Supply:

   • Connect the +V pin to a 3.3V or 5V power supply.
   • Connect the GND pin to the ground of your circuit.

2. Rotary Encoder Outputs:

   • Connect the CLK pin to a digital input pin on your microcontroller.
   • Connect the DT pin to another digital input pin on your microcontroller.

3. Push Button Output:

   • Connect the SW pin to a digital input pin on your microcontroller.

• Debouncing: Rotary encoders can produce noisy signals. Implement software debouncing to ensure accurate readings.
• Pull-up Resistors: Use internal or external pull-up resistors for the SW, CLK, and DT pins to ensure stable signals.
• Interrupts: For real-time applications, consider using hardware interrupts to handle the encoder signals.

// Rotary Encoder with Button Example Code for Arduino UNO

#define CLK 2  // Pin connected to CLK
#define DT 3   // Pin connected to DT
#define SW 4   // Pin connected to SW

int counter = 0;  // Counter to track encoder position
int currentStateCLK;
int lastStateCLK;
bool buttonPressed = false;

void setup() {
  pinMode(CLK, INPUT);
  pinMode(DT, INPUT);
  pinMode(SW, INPUT_PULLUP);  // Enable internal pull-up resistor

  // Read the initial state of CLK
  lastStateCLK = digitalRead(CLK);

  Serial.begin(9600);  // Initialize serial communication
}

void loop() {
  // Read the current state of CLK
  currentStateCLK = digitalRead(CLK);

  // If the state of CLK has changed, then we have a pulse
  if (currentStateCLK != lastStateCLK) {
    // If the DT state is different than the CLK state, then
    // the encoder is rotating counterclockwise
    if (digitalRead(DT) != currentStateCLK) {
      counter--;
    } else {
      // Encoder is rotating clockwise
      counter++;
    }

    Serial.print("Position: ");
    Serial.println(counter);
  }

  // Update the last state of CLK
  lastStateCLK = currentStateCLK;

  // Read the state of the push button
  if (digitalRead(SW) == LOW) {
    if (!buttonPressed) {
      Serial.println("Button Pressed");
      buttonPressed = true;
    }
  } else {
    buttonPressed = false;
  }
}

1. Noisy Signals:

   • Solution: Implement software debouncing to filter out noise.

2. Unstable Readings:

   • Solution: Ensure proper pull-up resistors are used for the SW, CLK, and DT pins.

3. Incorrect Direction Detection:

   • Solution: Verify the connections of the CLK and DT pins. Ensure they are correctly mapped in the code.

• Check Connections: Ensure all connections are secure and correctly mapped to the microcontroller pins.
• Use Serial Monitor: Utilize the Serial Monitor in Arduino IDE to debug and verify the encoder's output.
• Debounce Logic: Implement debounce logic in your code to handle noisy signals effectively.

By following this documentation, users can effectively integrate and utilize a rotary encoder with a button in their projects, ensuring accurate and reliable performance.