first, I Designed the base body in Fusion360 and 3D printed it on my Ender 3.

then I just put everything together like a jigsaw puzzle.

the main part of the heart of this project is the Mozzi Library here's the link for downloading it. http://sensorium.github.io/Mozzi/

after installing it, I uploaded the sketch based on this library to my Minimal Arduino Uno PCB which is basically a Breakout board for Atmega328PU (originally I made the circuit for a different thing but I end up using it instead of using a dot circuit board.

results were good but the sound is not loud because I have connected the speaker directly with Digital Pin 9

(will be adding an OPAMP circuit in this in future)

CODE-

#include <MozziGuts.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 // int freqVal; // desired carrier frequency max and min, for AutoMap
const int MIN_CARRIER_FREQ = 22;
const int MAX_CARRIER_FREQ = 440;

const int MIN = 1;
const int MAX = 10;

const int MIN_2 = 1;
const int MAX_2 = 15;

// 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);
AutoMap mapThis(0,1023,MIN,MAX);
AutoMap mapThisToo(0,1023,MIN_2,MAX_2);

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
const int LDR3_PIN=4;
const int LDR4_PIN=3;

Oscil<COS2048_NUM_CELLS, AUDIO_RATE> aCarrier(COS2048_DATA);
Oscil<COS2048_NUM_CELLS, AUDIO_RATE> aModulator(COS2048_DATA);
Oscil<COS2048_NUM_CELLS, 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);


void setup(){
//  Serial.begin(115200); // set up the Serial output so we can look at the light level  startMozzi(); // :))
}


void updateControl(){  //  freqVal = map(LDR3_PIN, 0, 1023, 1, 100);     int freqVal = mozziAnalogRead(LDR3_PIN); // value is 0-1023   int FRQ = mapThis(freqVal);      int knob2 = mozziAnalogRead(LDR4_PIN); // value is 0-1023   int knob2Val = mapThis(knob2);    // 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);    //calculate the modulation frequency to stay in ratio  int mod_freq = carrier_freq * mod_ratio * FRQ;    // 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 * knob2Val * (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...