/*  OLEDMeter was written to utilize any 128x64 display. I have only seen marginal attempts to
 *  animate meters and I hope this one will set a standard. Please feel free to modify and share
 *  this code for any 128x64 LCD or OLED. OLEDMeter sketch was written for use with I2C SSD1306.
 *  This code must be modified to work with other display devices.
 *  
 *  Working portion of code was taken from Adafruit Example Sound Level Sketch for the
 *  Adafruit Microphone Amplifier
 *  https://learn.adafruit.com/adafruit-microphone-amplifier-breakout/measuring-sound-levels
 *  
 *  Remaining code was written by Greg Stievenart with no claim to or any images or information 
 *  provided in this code. Freely published May 26, 2016.
 *  
 *  Software to convert background mask to 128x64 at: http://www.ablab.in/image2glcd-software/
 *  
 *  IMPORTANT: Sound source must be grounded to the Arduino or other MCU's to work. Usually the
 *  base sleeve contact on TRS or TRRS connector is the ground.
 */

#include <Wire.h>                     // requried to run I2C SSD1306
//#include <SPI.h>                      // requried to run I2C SSD1306
#include <Adafruit_GFX.h>             // https://github.com/adafruit/Adafruit-GFX-Library
#include <Adafruit_SSD1306.h>         // https://github.com/adafruit/Adafruit_SSD1306

#define OLED_RESET 4                  // reset required for SSD1306

Adafruit_SSD1306 display1(OLED_RESET);  // reset required for SSD1306
Adafruit_SSD1306 display2(OLED_RESET);  // reset required for SSD1306


int left = A0;                 // analog input for outside audio source
int right = A1;                 // analog input for outside audio source

int hMeter = 65;                      // horizontal center for needle animation
int vMeter = 85;                      // vertical center for needle animation (outside of dislay limits)
int rMeter = 80;                      // length of needle animation or arch of needle travel
float MeterValueLeft;
float MeterValueRight;
const int sampleWindow = 5;          // sample window width in mS (50 mS = 20Hz)
unsigned int sampleLeft;
unsigned int sampleRight;
unsigned int PeakRight = 400;                             // start needle fall max to min on start
unsigned int PeakLeft = 400;                             // start needle fall max to min on start
unsigned int fallTimeRight;          // needle fallspeed
unsigned int fallTimeLeft;          // needle fallspeed

// VU meter background mask image:
static const unsigned char PROGMEM VUMeter[] = { 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x1D, 0xC0, 0x00, 0x2E, 0x00, 0x00, 0x0E, 0x00, 0x00, 0xE0, 0x40, 0x1C, 0x00, 0x1C, 0x10, 
0x00, 0x05, 0x40, 0x00, 0x2A, 0x00, 0x00, 0x02, 0x00, 0x00, 0xA0, 0x40, 0x04, 0x00, 0x04, 0x10, 
0x1F, 0x1D, 0x40, 0x00, 0x2A, 0x00, 0x00, 0x0E, 0x00, 0x00, 0xA0, 0x40, 0x1C, 0x00, 0x1C, 0x7C, 
0x00, 0x11, 0x40, 0x00, 0x2A, 0x00, 0x00, 0x02, 0x00, 0x00, 0xA0, 0x40, 0x10, 0x00, 0x04, 0x10, 
0x00, 0x1D, 0xC0, 0x00, 0x2E, 0x00, 0x00, 0x0E, 0x00, 0x00, 0xE0, 0x40, 0x1C, 0x00, 0x1C, 0x10, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x02, 0x00, 0x00, 0x08, 0x00, 0x00, 0x04, 0x00, 0x00, 0x40, 0x40, 0x08, 0x00, 0x08, 0x00, 

0x00, 0x02, 0x00, 0x00, 0x08, 0x00, 0x00, 0x04, 0x00, 0x00, 0x40, 0x40, 0x08, 0x00, 0x08, 0x00, 
0x00, 0x02, 0x00, 0x00, 0x08, 0x08, 0x08, 0x04, 0x10, 0x40, 0x5F, 0xFF, 0xFF, 0xFF, 0xF8, 0x00, 
0x00, 0x03, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xDF, 0xFF, 0xFF, 0xFF, 0xF8, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x01, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xC0, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x01, 0x00, 0x00, 0x20, 0x00, 0x40, 0x01, 0x00, 0x10, 0x00, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x01, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x03, 0x80, 0x01, 0xDC, 0x02, 0x38, 0x0E, 0xE0, 0xEE, 0x05, 0xDC, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x02, 0x80, 0x00, 0x54, 0x02, 0xA8, 0x08, 0xA0, 0xAA, 0x05, 0x54, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x02, 0x80, 0x01, 0xD4, 0x02, 0xA8, 0x0E, 0xA0, 0xEA, 0x05, 0x54, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x02, 0x80, 0x01, 0x14, 0x03, 0xA8, 0x0A, 0xA0, 0xAA, 0x05, 0x54, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x03, 0x80, 0x01, 0xDC, 0x00, 0xB8, 0x0E, 0xE0, 0xEE, 0x05, 0xDC, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 

0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x41, 0x08, 0x20, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xA2, 0x94, 0x50, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xA2, 0x94, 0x50, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xA2, 0x94, 0x50, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xA2, 0x94, 0x50, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xA2, 0x94, 0x50, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xA2, 0x94, 0x50, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xA2, 0x94, 0x50, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 

0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xA2, 0x94, 0x50, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xA2, 0x94, 0x50, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x55, 0x14, 0x50, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x2A, 0x17, 0xD0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x14, 0x08, 0x20, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x08, 0x07, 0xC0, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 
};

void setup(){
  Serial.begin(9600);

  pinMode(left, INPUT);                             // analog input for outside audio source
    pinMode(right, INPUT);                             // analog input for outside audio source

  display1.begin(SSD1306_SWITCHCAPVCC, 0x3C);                // needed for SSD1306 display1    3C
  display1.clearDisplay();  // clears display from any library info displayed
  
  display2.begin(SSD1306_SWITCHCAPVCC, 0x3D);                // needed for SSD1306 display     3D
  display2.clearDisplay();                                  // clears display from any library info displayed
 
}

void loop(){

  unsigned long startMillis = millis();                    // start of sample window
  unsigned int PeaktoPeakLeft = 0;                             // peak-to-peak level
  unsigned int SignalMaxLeft = 0;
  unsigned int SignalMinLeft = 1024;
  unsigned int PeaktoPeakRight = 0;                             // peak-to-peak level
  unsigned int SignalMaxRight = 0;
  unsigned int SignalMinRight = 1024;
  while ( millis() - startMillis < sampleWindow ){

    sampleLeft = analogRead(left);
    sampleRight = analogRead(right);

    if (sampleLeft < 1024) {

      if (sampleLeft > SignalMaxLeft){

        SignalMaxLeft = sampleLeft;                                // saves just the max levels
      }

      else if (sampleLeft < SignalMinLeft){

        SignalMinLeft = sampleLeft;                                // saves just the min levels
      }
    }
    if (sampleRight < 1024) {

      if (sampleRight > SignalMaxRight){

        SignalMaxRight = sampleRight;                                // saves just the max levels
      }

      else if (sampleRight < SignalMinRight){

        SignalMinRight = sampleRight;                                // saves just the min levels
      }
    }
   
  }

  PeaktoPeakLeft = SignalMaxLeft - SignalMinLeft;                      // max - min = peak-peak amplitude
  PeaktoPeakRight = SignalMaxRight - SignalMinRight;                   // max - min = peak-peak amplitude

   if (PeaktoPeakLeft > PeakLeft){

        PeakLeft = PeaktoPeakLeft;// saves just the min levels
      }else if(PeaktoPeakLeft < PeakLeft){
        fallTimeLeft = ((PeakLeft - PeaktoPeakLeft) / 2);
        PeakLeft = PeakLeft-fallTimeLeft;
      }
   if (PeaktoPeakRight > PeakRight){

        PeakRight = PeaktoPeakRight;// saves just the min levels
      }else if(PeaktoPeakRight < PeakRight){
        fallTimeRight = ((PeakRight - PeaktoPeakRight) / 2);
        PeakRight = PeakRight-fallTimeRight;
      }

    

  MeterValueLeft = PeakLeft ;              // convert volts to arrow information sensitivity 
  MeterValueRight = PeakRight ;              // convert volts to arrow information sensitivity 

 drawleft();
 drawright();
}

void drawleft(){
  




  MeterValueLeft = MeterValueLeft - 34;                            // shifts needle to zero position
  display1.clearDisplay();                                  // refresh display for next step
  display1.drawBitmap(0, 0, VUMeter, 128, 64, WHITE);       // draws background white
  int a1 = (hMeter + (sin(MeterValueLeft / 57.296) * rMeter)); // meter needle horizontal coordinate
  int a2 = (vMeter - (cos(MeterValueLeft / 57.296) * rMeter)); // meter needle vertical coordinate
  
display1.drawLine(a1-2, a2, hMeter-1, vMeter, BLACK);         // draws needle
display1.drawLine(a1-1, a2, hMeter-1, vMeter, WHITE);         // draws needle  
display1.drawLine(a1, a2, hMeter, vMeter, WHITE);         // draws needle
display1.drawLine(a1+1, a2, hMeter+1, vMeter, WHITE);         // draws needle  
display1.drawLine(a1+2, a2, hMeter+1, vMeter, BLACK);         // draws needle
  display1.display();
}
void drawright(){
  




  MeterValueRight = MeterValueRight - 44;                            // shifts needle to zero position
  display2.clearDisplay();                                  // refresh display for next step
  display2.drawBitmap(0, 0, VUMeter, 128, 64, WHITE);       // draws background white
  int a1 = (hMeter + (sin(MeterValueRight / 57.296) * rMeter)); // meter needle horizontal coordinate
  int a2 = (vMeter - (cos(MeterValueRight / 57.296) * rMeter)); // meter needle vertical coordinate
  display1.drawLine(a1-2, a2, hMeter-1, vMeter, BLACK);         // draws needle
display1.drawLine(a1-1, a2, hMeter-1, vMeter, WHITE);         // draws needle  
display1.drawLine(a1, a2, hMeter, vMeter, WHITE);         // draws needle
display1.drawLine(a1+1, a2, hMeter+1, vMeter, WHITE);         // draws needle  
display1.drawLine(a1+2, a2, hMeter+1, vMeter, BLACK);         // draws needle
  display2.display();
}