ustd::FrequencyCounter Class Reference

#include <mup_frequency_counter.h>

Public Types
enum	InterruptMode { IM_RISING , IM_FALLING , IM_CHANGE }
enum	MeasureMode {   LOWFREQUENCY_FAST , LOWFREQUENCY_MEDIUM , LOWFREQUENCY_LONGTERM , HIGHFREQUENCY_FAST ,   HIGHFREQUENCY_MEDIUM , HIGHFREQUENCY_LONGTERM }

Public Member Functions
	FrequencyCounter (String name, uint8_t pin_input, int8_t interruptIndex_input, MeasureMode measureMode=HIGHFREQUENCY_MEDIUM, InterruptMode irqMode=InterruptMode::IM_FALLING)
void	setMeasureMode (MeasureMode mode, bool silent=false)
bool	begin (Scheduler *_pSched, uint32_t scheduleUs=2000000L)

Detailed Description

Interrupt driven frequency counter.

On an ESP32, measurement of frequencies at a GPIO are possible in ranges of 0-250kHz. There are six measurement modes: LOWFREQUENCY_FAST (good for measurements <50Hz, not much filtering) LOWFREQUENCY_MEDIUM (good for sub-Hertz enabled measurements, e.g. Geiger-counters) LOWFREQUENCY_LONGTERM (good for <50Hz, little deviation, high precision)

The HIGHFREQUENCY modes automatically reset the filter, if the input signal drops to 0Hz. HIGHFREQUENCY_FAST (no filtering) HIGHFREQUENCY_MEDIUM (some filtering) HIGHFREQUENCY_LONGTERM (strong filtering, good for precision measurement of signals with little deviation)

Precision <80kHz is better than 0.0005%. Interrupt load > 80kHz impacts the performance of the ESP32 severely and error goes up to 2-5%.

Messages

Messages sent by the switch mupplet:

topic	message body	comment
<mupplet-name>/sensor/frequency	53.001	Frequency in Hz encoded as String
<mupplet-name>/sensor/mode	[LOW,HIGH]FREQUENCY_[FAST,MEDIUM,LONGTERM]	Sample mode, e.g. LOWFREQUENCY_MEDIUM as string

Message received by the switch mupplet:

topic	message body	comment
<mupplet-name>/mode/set	[LOW,HIGH]FREQUENCY_[FAST,MEDIUM,LONGTERM]	Set the sample mode, e.g. LOWFREQUENCY_FAST, string encoded
<mupplet-name>/state/get		Causes current frequency to be sent with topic <mupplet-name>/sensor/frequency
<mupplet-name>/frequency/get		Causes current frequency to be sent with topic <mupplet-name>/sensor/frequency
<mupplet-name>/mode/get		Causes current sample mode to be sent with topic <mupplet-name>/sensor/mode

Member Enumeration Documentation

InterruptMode

enum ustd::FrequencyCounter::InterruptMode

Interrupt mode that triggers the counter

Enumerator
IM_RISING	trigger on rising signal (LOW->HIGH)
IM_FALLING	trigger on falling signal
IM_CHANGE	trigger on both rising and falling signal

MeasureMode

enum ustd::FrequencyCounter::MeasureMode

Sampling mode

Enumerator
LOWFREQUENCY_FAST	for measurements <50Hz, not much filtering
LOWFREQUENCY_MEDIUM	sub-Hertz enabled measurements, e.g. Geiger-counters
LOWFREQUENCY_LONGTERM	for <50Hz, little deviation, high precision, long-time averaging
HIGHFREQUENCY_FAST	no filtering
HIGHFREQUENCY_MEDIUM	some filtering
HIGHFREQUENCY_LONGTERM	strong filtering, good for precision measurement of signals with little deviation

Constructor & Destructor Documentation

FrequencyCounter()

ustd::FrequencyCounter::FrequencyCounter ( String  name, uint8_t  pin_input, int8_t  interruptIndex_input, MeasureMode  measureMode = HIGHFREQUENCY_MEDIUM, InterruptMode  irqMode = InterruptMode::IM_FALLING  )

inline

Create a frequency counter

Parameters

name	Name of mupplet, used in message topics
pin_input	GPIO of input signal
interruptIndex_input	a system wide unique index for the interrupt to be used [0...9]
measureMode	MeasureMode, e.g. LOWFREQUENCY_MEDIUM.
irqMode	InterruptMode, e.g. IM_RISING.

Member Function Documentation

begin()

bool ustd::FrequencyCounter::begin ( Scheduler *  _pSched, uint32_t  scheduleUs = 2000000L  )

inline

Enable interrupts and start counter

Parameters

_pSched	Pointer to scheduler
scheduleUs	Measurement schedule in microseconds

Returns

true if successful

setMeasureMode()

void ustd::FrequencyCounter::setMeasureMode ( MeasureMode  mode, bool  silent = false  )

inline

Change sample mode

Parameters

mode	MeasureMode, e.g. LOWFREQUENCY_MEDIUM.
silent	on true, no message is sent.

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

• src/mup_frequency_counter.h