Customize Knob_LightLevev_x2_FMSynth with others sensors

[Sal Mec]

Dear Community,
I would like to customize Knob_LightLevev_x2_FMSynth adding a distance sensor (VL53LXX-V2) replacing the frequency selection by KNOB_PIN with the distance measured by the sensor.
I'm able to run the original example on my Arduino UNO clone and I can hear a good quality sound, but when I add the sensor I can hear some rithmic noise.
I have read about refresh rate issue and I have choosen 128 Hz (I've also tried 256 and 64Hz) but without success.
I've also commented all Serial.print and choose all different speed on Serial communication from 9600 up to 115200 but the noise is still present and is not affected by serial speed.
I normally power the Arduino though USB, but I've tryed also a different power switching and a new 9V battery, with the same results.
How can I avoid the noise issue?
below the code (the added code to the original exampled are marked by comments):
//CODE

#define MOZZI_ANALOG_READ_RESOLUTION 10  // code below assumes readings to be in the classic 10-bit (0-1023) range

#include <Mozzi.h>

#include <Oscil.h>                // oscillator

#include <tables/cos2048_int8.h>  // table for Oscils to play

#include <Smooth.h>

#include <AutoMap.h>  // maps unpredictable inputs to a range

// desired carrier frequency max and min, for AutoMap

const int MIN_CARRIER_FREQ = 22;

const int MAX_CARRIER_FREQ = 440;

// desired intensity max and min, for AutoMap, note they're inverted for reverse dynamics

const int MIN_INTENSITY = 700;

const int MAX_INTENSITY = 10;

// desired mod speed max and min, for AutoMap, note they're inverted for reverse dynamics

const int MIN_MOD_SPEED = 10000;

const int MAX_MOD_SPEED = 1;

AutoMap kMapCarrierFreq(0, 1023, MIN_CARRIER_FREQ, MAX_CARRIER_FREQ);

AutoMap kMapIntensity(0, 1023, MIN_INTENSITY, MAX_INTENSITY);

AutoMap kMapModSpeed(0, 1023, MIN_MOD_SPEED, MAX_MOD_SPEED);

const int KNOB_PIN = 0;  // set the input for the knob to analog pin 0

const int LDR1_PIN = 1;  // set the analog input for fm_intensity to pin 1

const int LDR2_PIN = 2;  // set the analog input for mod rate to pin 2

Oscil<COS2048_NUM_CELLS, MOZZI_AUDIO_RATE> aCarrier(COS2048_DATA);

Oscil<COS2048_NUM_CELLS, MOZZI_AUDIO_RATE> aModulator(COS2048_DATA);

Oscil<COS2048_NUM_CELLS, MOZZI_CONTROL_RATE> kIntensityMod(COS2048_DATA);

int mod_ratio = 5;  // brightness (harmonics)

long fm_intensity;  // carries control info from updateControl to updateAudio

// smoothing for intensity to remove clicks on transitions

float smoothness = 0.95f;

Smooth<long> aSmoothIntensity(smoothness);

#define CONTROL_RATE 128 // Hz, powers of 2 are most reliable

//ADD SENSOR

#include <Wire.h>

#include <VL53L0X.h>

VL53L0X sensor;

// END ADD SENSOR

void setup() {

  //Serial.begin(9600); // for Teensy 3.1, beware printout can cause glitches

  Serial.begin(115200);  // set up the Serial output so we can look at the piezo values // set up the Serial output so we can look at the light level

  startMozzi(CONTROL_RATE);          // :))

  //ADD SENSOR

  Wire.begin();

  sensor.init();

  sensor.setTimeout(500);

    // Start continuous back-to-back mode (take readings as

    // fast as possible).  To use continuous timed mode

    // instead, provide a desired inter-measurement period in

    // ms (e.g. sensor.startContinuous(100)).

    sensor.startContinuous();

  //END ADD SENSOR

}

void updateControl() {

  // read the knob

  int knob_value = mozziAnalogRead(KNOB_PIN);  // value is 0-1023

  // map the knob to carrier frequency

  //  int carrier_freq = kMapCarrierFreq(knob_value);

  int carrier_freq = sensor.readRangeContinuousMillimeters();

  //calculate the modulation frequency to stay in ratio

  int mod_freq = carrier_freq * mod_ratio;

  // set the FM oscillator frequencies

  aCarrier.setFreq(carrier_freq);

  aModulator.setFreq(mod_freq);

  // read the light dependent resistor on the width Analog input pin

  int LDR1_value = mozziAnalogRead(LDR1_PIN);  // value is 0-1023

  // print the value to the Serial monitor for debugging

 /* Serial.print("LDR1 = ");

  Serial.print(LDR1_value);

  Serial.print("\t");  // prints a tab*/

 

  int LDR1_calibrated = kMapIntensity(LDR1_value);

 /* Serial.print("LDR1_calibrated = ");

  Serial.print(LDR1_calibrated);

  Serial.print("\t");  // prints a tab*/

  // calculate the fm_intensity

  fm_intensity = ((long)LDR1_calibrated * (kIntensityMod.next() + 128)) >> 8;  // shift back to range after 8 bit multiply

 /* Serial.print("fm_intensity = ");

  Serial.print(fm_intensity);

  Serial.print("\t");  // prints a tab*/

  // read the light dependent resistor on the speed Analog input pin

  int LDR2_value = mozziAnalogRead(LDR2_PIN);  // value is 0-1023

/*  Serial.print("LDR2 = ");

  Serial.print(LDR2_value);

  Serial.print("\t");  // prints a tab*/

  // use a float here for low frequencies

  float mod_speed = (float)kMapModSpeed(LDR2_value) / 1000;

 /* Serial.print("   mod_speed = ");

  Serial.print(mod_speed);

  kIntensityMod.setFreq(mod_speed);

  Serial.println();  // finally, print a carraige return for the next line of debugging info*/

}

AudioOutput updateAudio() {

  long modulation = aSmoothIntensity.next(fm_intensity) * aModulator.next();

  return MonoOutput::from8Bit(aCarrier.phMod(modulation));

}

void loop() {

  audioHook();

}

//END CODE

Thanks in advance

Salmec

[tomco...@live.fr]

Hi,

Sorry for the delay.

Does this also happens with the sensor connected (and updated) but if you are not using the data from the sensor for the synthesis?

If no, this seems to mean that the data from the sensor is noisy (picking up the mains or something). One way to solve that in soft would be to Smooth or LowPass the sensor output. In hardware, it would be interesting for you to have a look at the actual output of the sensor, for instance with a scope if you have one, to have an idea of the noise.

Hope this helps,

Tom

[Mozzi-users]

It's possible that the I2C communication with the VL53LXX-V2 sensor is blocking the audio - the Mozzi example 11.Communication>2Wire_Read_ADXL345 shows a way to work around it if that's the problem...

If working out the nonblocking code is too time-consuming and you don't need that particular sensor (VL53LXX-V2), the HC-SR04 ultrasonic distance sensor is easy to use (but also requires a fairly simple workaround in Mozzi).  I can post a sketch if you go that way.

[Sal Mec]

Dear Tom,

thanks for your interest and suggestion, I've made some test in order to understand better the situation:

1) deleting all sensor reference, the sound comes with a good quality the frequency selection is done by A0 analogread 

  int knob_value = mozziAnalogRead(KNOB_PIN);

int carrier_freq = kMapCarrierFreq(knob_value);

2) in the setup I've initialized the sensor

  Wire.begin();

  sensor.init();

  sensor.setTimeout(500);

  sensor.startContinuous(CONTROL_RATE);

but data are not taken from the sensor

 //int carrier_freq = sensor.readRangeContinuousMillimeters(); is still commented

the audio quality is good.

3) if I take data from sensor

 int carrier_freq = sensor.readRangeContinuousMillimeters();

the audio output is affected by noise...

I've tried also to change sensor.startContinuous(CONTROL_RATE);

with sensor.startContinuous(64); without any upgrade...

any other suggestion?

Regarding HC-SR04, I can test it so a working example is highly appreciated 

thanks a lot

Salmec

[Mozzi-users]

Here's the hc-sr04 example..

[Sal Mec]

Thanks,

I'll try with HC-SR04 sensor, but I would like to implement Laser distance with IC2 communication, any other suggestion or troubleshoting?

Thanks in advance 

Salmec