PulseIn Class Reference

A class to measure the duration of a pulse on a digital pin. More...

#include <PulseIn.h>

Public Member Functions
	PulseIn (BelaContext *context, unsigned int digitalInput, int direction=1)
void	setup (BelaContext *context, unsigned int digitalInput, int direction=1)
void	check (BelaContext *context)
int	hasPulsed (BelaContext *context, unsigned int frame)
void	cleanup ()

Detailed Description

A class to measure the duration of a pulse on a digital pin.

This can be used to measure distance in conjunction with an ultrasonic ranging sensor (e.g.: HC-SR04).

Examples:

Sensors/ultrasonic-distance-sensor/render.cpp.

Constructor & Destructor Documentation

PulseIn::PulseIn ( BelaContext *  context, unsigned int  digitalInput, int  direction = 1  )

inline

Initializes the PulseIn object. Also takes care of setupializing the digital pin as input.

Parameters

context	the BelaContext
digitalInput	the digital input where to activate a pulse detector
direction	the direction of the pulse, can be 1 to detect positive pulses, e.g.:( 0 0 0 0 1 1 0 0 0 0 0) or -1 to detect negative pulses, e.g.: ( 1 1 1 1 0 0 1 1 1 1)

Member Function Documentation

void PulseIn::setup	(	BelaContext *	context,
		unsigned int	digitalInput,
		int	direction = 1
	)

Initializes the PulseIn object. Also takes care of initializing the digital pin as input.

If the object has been created with the default constructor, the user will need to call setup() before calling check() or hasPulsed().

Parameters

context	the BelaContext
digitalInput	the digital input where to activate a pulse detector
direction	the direction of the pulse, can be 1 to detect positive pulses, e.g.:( 0 0 0 0 1 1 0 0 0 0 0) or -1 to detect negative pulses, e.g.: ( 1 1 1 1 0 0 1 1 1 1)

Examples:

Sensors/ultrasonic-distance-sensor/render.cpp.

void PulseIn::check

(

BelaContext *

context

)

Detects pulses.

The user does not need to call this method as long as they call hasPulsed() at least once per context. The rationale why we check() for pulses in a different method than hasPulsed() is because user might not query for hasPulsed() every sample, so we are safe so long as they call hasPulsed() or check() at least once per buffer. Also, results are cached (i.e.: we do not check() for pulses twice for the same context. context->audioFramesElapsed is used as an identifier.

int PulseIn::hasPulsed ( BelaContext *  context, unsigned int  frame  )

inline

Looks for the end of a pulse.

Parameters

context	the current BelaContext
frame	the frame at which to check if a pulse was detected.

Returns

the length of the pulse if a pulse ending was detected at sample n, zero otherwise.

Examples:

Sensors/ultrasonic-distance-sensor/render.cpp.

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

• libraries/PulseIn/PulseIn.h
• libraries/PulseIn/PulseIn.cpp