mathertel/rotaryencoder

You can initialize a RotaryEncoder instance in two ways depending on whether you want to handle hardware pin configuration immediately or manually later.

1. With Hardware Initialization: Pass the two encoder pins and a LatchMode. This automatically configures the pins, enables internal pull-up resistors, and establishes the initial position.
2. Without Hardware Initialization: Use the constructor that only takes a LatchMode. This is useful if you want to configure pins manually or use a different initialization strategy.

Use NO_PIN (defined as -1) to skip hardware configuration for a specific pin.

// Hardware initialization (recommended)
RotaryEncoder encoder(2, 3, RotaryEncoder::LatchMode::FOUR0);

// Manual initialization (no hardware setup)
RotaryEncoder encoder(RotaryEncoder::LatchMode::FOUR0);

The LatchMode enum defines how the encoder's state changes are interpreted, allowing you to adjust sensitivity or accommodate different wiring configurations.

• FOUR3: 4 steps, Latch at position 3 only (compatible with older versions).
• FOUR0: 4 steps, Latch at position 0 (standard for many encoders, handles reverse wirings).
• TWO03: 2 steps, Latch at position 0 and 3.

// Example using TWO03 mode
RotaryEncoder encoder(2, 3, RotaryEncoder::LatchMode::TWO03);

Use the following methods to retrieve the current state of the encoder:

• getPosition(): Returns the current long position.
• getDirection(): Returns a RotaryEncoder::Direction enum representing the last movement:
  • Direction::NOROTATION (0)
  • Direction::CLOCKWISE (1)
  • Direction::COUNTERCLOCKWISE (-1)
• setPosition(long newPosition): Manually sets the current position.

long pos = encoder.getPosition();
RotaryEncoder::Direction dir = encoder.getDirection();

if (dir == RotaryEncoder::Direction::CLOCKWISE) {
  // Handle clockwise rotation
}

To process encoder movement, you must call the tick() method regularly (e.g., in your main loop or via an interrupt).

• Standard tick(): Uses digitalRead() on the pins provided during construction. This is the simplest method but has higher overhead.
• High-performance tick(int sig1, int sig2): Allows you to pass the raw pin values directly. Use this if you have a faster way to read pins than digitalRead() or are calling it from an interrupt where you've already captured the state.

// Standard usage in loop
void loop() {
  encoder.tick();
}

// High-performance usage (passing values directly)
void loop() {
  int s1 = digitalRead(2);
  int s2 = digitalRead(3);
  encoder.tick(s1, s2);
}

The library provides built-in support for measuring the speed of rotation:

• getRPM(): Returns the current Revolutions Per Minute (RPM) as an unsigned long.
• getMillisBetweenRotations(): Returns the time in milliseconds between the current and previous observed rotation.

unsigned long rpm = encoder.getRPM();
unsigned long msBetween = encoder.getMillisBetweenRotations();