BufferedSampler Class Reference

Ringbuffer-based sampler for analog values. More...

#include <BufferedSampler.h>

Inheritance diagram for BufferedSampler:

Public Member Functions
	BufferedSampler (const uint8_t pin, const uint16_t periodMs=10, const uint8_t samples=10)
	~BufferedSampler ()
virtual void	begin ()
virtual void	update ()
virtual int16_t	minimum ()
	The minimum value in the sample set.
virtual int16_t	maximum ()
	The maximum value in the sample set.
virtual float	average ()
	Get the mean value in the sample set.
virtual uint8_t	count ()
virtual int16_t	last ()
	Get the most recent sample value.
Public Member Functions inherited from AbstractSampler
	AbstractSampler (const uint8_t pin, const uint16_t periodMs)
virtual	~AbstractSampler ()
	Destructor.
uint8_t	pin ()
	Accessor for the pin which is geting read from.

Protected Member Functions
virtual void	calculate ()
	calculate avg, min, max if required

Protected Attributes
uint8_t	_samples
	max number of samples to keep in buffer
uint8_t	_idx
	index ptr (ring buffer)
uint8_t	_count
	number of samples in buffer
uint32_t	_lastUpdated
	when last sample taken
bool	_updated
	flag to re-calulate avg or not
int16_t *	_sampleData
	ring buffer for data
int16_t	_minimum
	most recently calculated minimum value
int16_t	_maximum
	most recently calculated maximum value
float	_mean
	most recently calculated mean value
Protected Attributes inherited from AbstractSampler
const uint8_t	_pin
	pin to read data from
const uint16_t	_periodMs
	minimum ms

Detailed Description

Ringbuffer-based sampler for analog values.

This class keeps a fixed number of samples in a ring buffer, enabling calculation of minimum(), maximum(), average() (mean) values.

Advantages:

• calculates actual mean value for samples in buffer
• provides minimum() and maximum() values for values in buffer

Disadvantages:

• memory usage increases with number of samples
• takes longer to calculate than exponential moving average

Definition at line 19 of file BufferedSampler.h.

Constructor & Destructor Documentation

BufferedSampler()

BufferedSampler::BufferedSampler	(	const uint8_t	pin,
		const uint16_t	periodMs = 10,
		const uint8_t	samples = 10
	)

Constructor

Parameters

pin	the analog input pin to read samples from
periodMs	the number of milliseconds between samples. If update() is called before periodMs has passed since the last update(), no sample will be taken.
samples	the number of samples to keep in the ring buffer used to calculate average(), minimum() and maximum().

Note: this class dynamically allocated memory for the ring buffer.

Definition at line 6 of file BufferedSampler.cpp.

~BufferedSampler()

BufferedSampler::~BufferedSampler

(

)

Destructor

Destroy the BufferedSampler, and free memory used for the ring buffer.

Definition at line 21 of file BufferedSampler.cpp.

Member Function Documentation

begin()

void BufferedSampler::begin ( )

virtual

Initialization Should be called before the object is used, and may also be called at any other time to clear the ring buffer. Immediately after begin() is called, average(), minimum() and maximum() will return 0.

Reimplemented from AbstractSampler.

Definition at line 29 of file BufferedSampler.cpp.

count()

virtual uint8_t BufferedSampler::count ( )

inlinevirtual

Sample count The number of samples currently held in the ring buffer which are being used to calculate the average, minimum, maximum values. This will be 0 after the BufferedSampler has been constructed or begin() called, and will rise by 1 each time a sample is taken until the maximum number of samples is reached.

Definition at line 69 of file BufferedSampler.h.

update()

void BufferedSampler::update ( )

virtual

Time slice allocation This method should be called every time a sample is to be taken. If the BufferedSampler object was constucted with periodMs > 0, this method will only add a new sample to the ring buffer if at least periodMs milliseconds has elapsed since the last call to update().

Implements AbstractSampler.

Definition at line 41 of file BufferedSampler.cpp.

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The documentation for this class was generated from the following files:

• src/BufferedSampler.h
• src/BufferedSampler.cpp