DigitalIn

A digital (ie. binary) input unit that can be either “on” or “off”.

The unit is assigned to a specific pin on the board.

The mode specifies the behavior of the component attached to the pin:

  • in DIRECT mode (default) the unit will be “on” when the voltage on the pin is high (Vref, typically 5V)

  • in INVERTED mode the unit will be “on” when the voltage on the pin is low (GND)

  • in INTERNAL_PULLUP mode the internal pullup resistor is used, simplifying usage of switches and buttons

Debouncing

Some digital inputs such as push-buttons often generate spurious open/close transitions when pressed, due to mechanical and physical issues: these transitions called “bouncing” may be read as multiple presses in a very short time, fooling the program.

The DigitalIn object features debouncing capabilities which can prevent this kind of problems. Debouncing can be achieved using different modes: stable (default) (DEBOUNCE_STABLE), lock-out (DEBOUNCE_LOCK_OUT) and prompt-detect (DEBOUNCE_PROMPT_DETECT). For more information please refer to the documentation of the Bounce2 Arduino Library.

Example

Turns on and off a light emitting diode (LED) connected to digital pin 13, when pressing a pushbutton attached to digital pin 2. Pushbutton should be wired by connecting one side to pin 2 and the other to ground.

#include <Plaquette.h>

DigitalIn button(2, INTERNAL_PULLUP);

DigitalOut led(13);

void begin() {
  button.debounce(); // debounce button
}

void step() {
  // Toggle the LED each time the button is pressed.
  if (button.rose())
    led.toggle();
}

Reference

class DigitalIn : public DigitalSource, public PinConfig, public Debounceable

A generic class representing a simple digital input.

Public Functions

DigitalIn(uint8_t pin, Engine &engine = Engine::primary())

Constructor.

Parameters

  • pin – the pin number

  • mode – the mode (DIRECT, INVERTED, or INTERNAL_PULLUP)

virtual void mode(uint8_t mode)

Changes the mode of the component.

float read() const

Directly reads value from the pin as 1 or 0 (bypasses mode, debounce, and engine).

int rawRead() const

Directly reads raw value from the pin as HIGH or LOW (bypasses mode, debounce, and engine).

inline virtual bool isOn()

Returns true iff the input is “on”.

inline virtual bool putOn(bool value)

Pushes value into the unit.

Parameters

value – the value sent to the unit

Returns

the new value of the unit

inline virtual bool rose()

Returns true if the value rose.

inline virtual bool fell()

Returns true if the value fell.

inline virtual bool changed()

Returns true if the value changed.

inline virtual bool toggle()

Switches between on and off.

inline virtual int8_t changeState()

Difference between current and previous value of the unit.

inline virtual void onRise(EventCallback callback)

Registers event callback on rise event.

inline virtual void onFall(EventCallback callback)

Registers event callback on fall event.

inline virtual void onChange(EventCallback callback)

Registers event callback on change event.

inline virtual bool isOff()

Returns true iff the input is “off”.

inline virtual int getInt()

Returns value as integer (0 or 1).

inline virtual float get()

Returns value as float (either 0.0 or 1.0).

inline virtual bool on()

Sets output to “on” (ie. true, 1).

inline virtual bool off()

Sets output to “off” (ie. false, 0).

inline virtual float put(float value)

Pushes value into the unit.

Parameters

value – the value sent to the unit

Returns

the new value of the unit

inline virtual float mapTo(float toLow, float toHigh)

Maps value to new range.

inline operator bool()

Operator that allows usage in conditional expressions.

inline float seconds() const

Returns engine time in seconds.

inline uint32_t milliSeconds() const

Returns engine time in milliseconds.

inline uint64_t microSeconds() const

Returns engine time in microseconds.

inline unsigned long nSteps() const

Returns number of engine steps.

inline float sampleRate() const

Returns engine sample rate.

inline float samplePeriod() const

Returns enginesample period.

inline uint8_t pin() const

Returns the pin this component is attached to.

inline uint8_t mode() const

Returns the mode of the component.

inline virtual void debounce(float debounceTime = PLAQUETTE_DEFAULT_DEBOUNCE_WINDOW)

Apply smoothing to object.

inline virtual void noDebounce()

Remove smoothing.

inline virtual void smooth(float smoothTime = PLAQUETTE_DEFAULT_DEBOUNCE_WINDOW)

Deprecated. Left for backwards compatibility.

inline virtual void noSmooth()

Remove smoothing.

inline virtual void timeWindow(float seconds)

Changes the debouncing window (expressed in seconds).

inline float timeWindow() const

Returns the debouncing window (expressed in seconds).

inline uint8_t debounceMode() const

Returns the debounce mode.

inline void debounceMode(uint8_t mode)

Sets debounce mode.

Parameters

mode – the debounce mode (DEBOUNCE_DEFAULT, DEBOUNCE_LOCK_OUT or DEBOUNCE_PROMPT_DETECT)

Public Static Functions

static inline bool analogToDigital(float f)

Converts analog (float) value to digital (bool) value.

static inline float digitalToAnalog(bool b)

Converts digital (bool) value to analog (float) value.

See Also