core_analysis.cpp File Reference

#include <Arduino.h>
#include "arduinoFFT.h"
#include "nanolux_types.h"
#include "nanolux_util.h"
#include <cmath>

Functions
void	sample_audio ()
	Samples incoming audio and stores the signal in vReal.
void	noise_gate (int threshhold)
	Zeros all audio analysis arrays if the volume is too low.
void	update_volume ()
	Calculates and stores the current volume.
void	update_max_delta ()
	Updates the largest frequency change in the last cycle.
void	update_peak ()
	Updates the current peak frequency.

Variables
unsigned int	sampling_period_us
	Audio sampling period.
double	volume
	Global variable used to access the current volume.
double	peak
	Global variable used to store preak audio frequency.
bool	is_fft_initalized = false
double	vReal [SAMPLES]
double	vRealHist [SAMPLES]
	Last state of the vReal array.
double	vImag [SAMPLES]
	Imaginary component of vReal. Unused.
double	delt [SAMPLES]
ArduinoFFT< double >	FFT = ArduinoFFT<double>(vReal, vImag, SAMPLES, SAMPLING_FREQUENCY)
	FFT used for processing audio.
double	maxDelt

Detailed Description

This file's functions perform basic audio processing.

Many of the functions in ext_analysis.cpp use values calculated here to perform more complex audio analysis.

Function Documentation

noise_gate()

void noise_gate

(

int

threshhold

)

Zeros all audio analysis arrays if the volume is too low.

Parameters

threshold

The threshold to compare the total volume against.

sample_audio()

void sample_audio

(

)

Samples incoming audio and stores the signal in vReal.

Reads from ANALOG_PIN for the calculated sampling period. Once a timestep is sampled, the function sleeps until ready to sample again at the next timestep.

update_max_delta()

void update_max_delta

(

)

Updates the largest frequency change in the last cycle.

Places the calculated value in the "maxDelt" variable.

update_peak()

void update_peak

(

)

Updates the current peak frequency.

Places the calculated peak frequency in the "peak" variable.

update_volume()

void update_volume

(

)

Calculates and stores the current volume.

Volume is stored in the "volume" global variable.

Variable Documentation

delt

double delt[SAMPLES]

extern

Variable used to store the frequency delta between vReal and vRealHist.

maxDelt

double maxDelt

extern

Global variable used to access the frequency band with the largest delta between iterations.

peak

double peak

extern

Global variable used to store preak audio frequency.

Global variable used to store preak audio frequency.

volume

double volume

extern

Global variable used to access the current volume.

Global variable used to access the current volume.

vReal

double vReal[SAMPLES]

extern

Array to store both sampled and FFT'ed audio. Processing is done in place.