Smoother

Smooths the incoming signal by removing fast variations and noise (high frequencies).

_images/Plaquette-Smooth.png

Example

Smooth a sensor over time.

#include <Plaquette.h>

AnalogIn sensor(A0);

// Smooths over time window of 10 seconds.
Smoother smoother(10.0);

StreamOut serialOut(Serial);

void begin() {}

void step() {
  // Smooth value and send it to serial output.
  sensor >> smoother >> serialOut;
}

Note

The filter uses an exponential moving average which corresponds to a form of low-pass filter.

Reference

class Smoother : public Unit, public MovingAverage

Simple moving average transform filter.

Public Functions

Smoother(Engine &engine = Engine::primary())

Constructor with default smoothing.

Parameters:

engine – the engine running this unit

Smoother(float smoothingWindow, Engine &engine = Engine::primary())

Constructor with smoothing window.

Parameters:

  • smoothingWindow – the time window over which the smoothing applies (in seconds)

  • engine – the engine running this unit

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 get()

Returns smoothed value.

void timeWindow(float seconds)

Changes the smoothing window (expressed in seconds).

inline float timeWindow() const

Returns the smoothing window (expressed in seconds).

void cutoff(float hz)

Changes the smoothing window cutoff frequency (expressed in Hz).

float cutoff() const

Returns the smoothing window cutoff frequency (expressed in Hz).

See Also