#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
// Declaration for an SSD1306 display connected to I2C (SDA, SCL pins)
#define OLED_RESET     4 // Reset pin # (or -1 if sharing Arduino reset pin)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

int Ve=13,calibre=1,intervlow=0,intervhigh=0; /* Applique le 5V*/ /*la var calibre permet de changer de calibre de mesure*/
const int ref1=1000,ref2=10000,ref3=100000,ref4=1000000; /*Résistance de référence de différent calibre*/
const int etat_bas1= 5; 
const int etat_bas2= 6;
const int etat_bas3= 7;
const int etat_bas4= 8; /* D5 pour ref1 | D6 pour ref2 | D7 pour ref3 | D8 pour ref4 */
int Rm=0; /* Résistance à mesurer */
float buffer=0,input=A0,Vs=0; /* la variable buffer récupère la tension mesuré | input est la sonde de tension | Vs la tension de sortie*/
int x=1,y=1,i=0; /* variable qui commande la position de la fonction ohmlogo | i est utilisé dans le setup*/

void setup()
{
  Serial.begin(9600);
  pinMode(Ve, OUTPUT);
  pinMode(etat_bas1, OUTPUT);
  pinMode(etat_bas2, OUTPUT);
  pinMode(etat_bas3, OUTPUT);
  pinMode(etat_bas4, OUTPUT);
  pinMode(input, INPUT);  
  if(!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) { 
  Serial.println(F("SSD1306 allocation failed"));
  for(;;); 
  }
  display.setTextSize( 2 );
  display.setTextColor( WHITE );
  display.clearDisplay();
  display.setTextSize(2);
  display.setCursor(20,6);
  display.println("Ohmmetre");
  display.setTextSize(1);
  display.setCursor(20,25);
  display.println("By DRS");
  ohmlogo();
  res();
  for(i=0;i<=100;i++)
  {
      display.setTextSize( 2 );
      display.setTextColor( WHITE );
      display.clearDisplay();
      display.setTextSize(2);
      display.setCursor(20,6);
      display.println("Ohmmetre");
      display.setTextSize(1);
      display.setCursor(20,25);
      display.println("By DRS");
      ohmlogo();
      res(); 
      display.setTextSize(2);
      display.setCursor(65,35);
      display.print(i);
      display.println(" %");   
      delay(15);
      display.display(); 
  }
  delay(500);
}

void loop()
{
      switch(calibre){
      case 1: /* calibre 0-1k*/  
          Serial.println("Cas n°1");               
          delay(500);
          digitalWrite(Ve, HIGH);          /* Applique le 5v */
          pinMode(etat_bas1,OUTPUT);       /* GND            */
          pinMode(etat_bas2, INPUT);       /* HZ             */
          pinMode(etat_bas3, INPUT);       /* HZ             */
          pinMode(etat_bas4, INPUT);       /* HZ             */
          digitalWrite(etat_bas1, LOW);
          Vs = analogRead(input);
          buffer = ((Vs/1024.0)*5);
          Rm = (((5/buffer)-1)*ref1);
          intervlow = ref1-(ref1*0.1);
          intervhigh = ref1+(ref1*0.1);  
          if(Rm==0){   rmnull();   }          
          else{
              if(((Rm>=intervlow)&&(Rm<=intervhigh)) || (Rm<=ref1)){
                display.clearDisplay();
                display.setTextColor(WHITE);
                display.clearDisplay();
                display.setTextSize(1);
                display.setCursor(5,20);
                display.println("La resistance vaut: ");
                display.setTextSize(2);
                display.setCursor(15,35);
                display.print(Rm);
                display.println(" Ohm");
                display.display();
                calibre=1;
                delay(2500);
                }  
                else{
                    calibre = 2; /* permet de changer le calibre */
                }   
          }
          break;
      case 2: /* calibre 1k-10k*/
          Serial.println("Cas n°2");
          delay(500);
          digitalWrite(Ve, HIGH);          /* Applique le 5v */
          pinMode(etat_bas2, OUTPUT);      /* GND            */
          pinMode(etat_bas1, INPUT);       /* HZ             */
          pinMode(etat_bas3, INPUT);       /* HZ             */
          pinMode(etat_bas4, INPUT);       /* HZ             */
          digitalWrite(etat_bas2, LOW); 
          Vs = analogRead(input);
          buffer = ((Vs/1024.0)*5);
          Rm = (((5/buffer)-1)*ref2);
          intervlow = ref2-(ref2*0.1);
          intervhigh = ref2+(ref2*0.1);                 
          if(Rm==0){   rmnull(); }    
          else{
              if((Rm>=intervlow)&&(Rm<=intervhigh) || (Rm<=ref2)){        
                display.clearDisplay();
                display.setTextColor(WHITE);
                display.clearDisplay();
                display.setTextSize(1);
                display.setCursor(5,20);
                display.println("La resistance vaut: ");
                display.setTextSize(2);
                display.setCursor(15,35);
                display.print(Rm);
                display.println(" Ohm");
                display.display();       
                calibre=1;
                delay(2500);
                }
                else{
                  calibre = 3; /* permet de changer le calibre */
                }    
          }
          break;
      case 3:
          Serial.println("Cas n°3");
          delay(500);  /* calibre 10k-100k*/
          digitalWrite(Ve, HIGH);          /* Applique le 5v */
          pinMode(etat_bas3, OUTPUT);      /* GND            */
          pinMode(etat_bas1, INPUT);       /* HZ             */
          pinMode(etat_bas2, INPUT);       /* HZ             */
          pinMode(etat_bas4, INPUT);       /* HZ             */
          digitalWrite(etat_bas3, LOW); 
          Vs = analogRead(input);
          buffer = ((Vs/1024.0)*5);
          Rm = (((5/buffer)-1)*ref3);
          intervlow = ref3-(ref3*0.1);
          intervhigh = ref3+(ref3*0.1);
          if(Rm==0){     rmnull(); }
          else{
              if((Rm>=intervlow)&&(Rm<=intervhigh) || (Rm<=ref3)){            
                display.clearDisplay();
                display.setTextColor(WHITE);
                display.clearDisplay();
                display.setTextSize(1);
                display.setCursor(5,20);
                display.println("La resistance vaut: ");
                display.setTextSize(1);
                display.setCursor(15,35);
                display.print(Rm);
                display.println(" Ohm");
                display.display();       
                calibre=1;
                delay(2500);
                }
                else{
                  calibre = 4; /* permet de changer le calibre */
                }  
          }
          break;
       case 4:
          Serial.println("Cas n°4");
          delay(500);  /* calibre 100k-1M*/
          digitalWrite(Ve, HIGH);          /* Applique le 5v */
          pinMode(etat_bas3, OUTPUT);      /* GND            */
          pinMode(etat_bas1, INPUT);       /* HZ             */
          pinMode(etat_bas2, INPUT);       /* HZ             */
          pinMode(etat_bas4, INPUT);       /* HZ             */
          digitalWrite(etat_bas3, LOW); 
          Vs = analogRead(input);
          buffer = ((Vs/1024.0)*5);
          Rm = (((5/buffer)-1)*ref4);
          intervlow = ref4-(ref4*0.1);
          intervhigh = ref4+(ref4*0.1);
          if(Rm==0){  rmnull();   }
          else{
              if((Rm>=intervlow)&&(Rm<=intervhigh) || (Rm<=ref4)){          
                display.clearDisplay();
                display.setTextColor(WHITE);
                display.clearDisplay();
                display.setTextSize(1);
                display.setCursor(5,20);
                display.println("La resistance vaut: ");
                display.setTextSize(1);
                display.setCursor(15,35);
                display.print(Rm);
                display.println(" Ohm");
                display.display();       
                calibre=1;
                delay(2500);  
                }
                else{
                    /* calibre = 4;  permet de changer le calibre si vous souhaitez un ajouter un */
                }      
          }   
          break;
      default:
          break;
   }      
}

void ohmlogo(){
  display.drawPixel(x+2,y+18,WHITE);  display.drawPixel(x+2,y+19,WHITE);  display.drawPixel(x+3,y+19,WHITE);  display.drawPixel(x+4,y+19,WHITE);  display.drawPixel(x+5,y+19,WHITE);
  display.drawPixel(x+5,y+18,WHITE);  display.drawPixel(x+4,y+17,WHITE);  display.drawPixel(x+3,y+16,WHITE); display.drawPixel(x+3,y+15,WHITE); display.drawPixel(x+3,y+14,WHITE); display.drawPixel(x+4,y+13,WHITE);  display.drawPixel(x+5,y+12,WHITE);
  display.drawPixel(x+6,y+11,WHITE);  display.drawPixel(x+7,y+11,WHITE); display.drawPixel(x+8,y+11,WHITE); display.drawPixel(x+9,y+11,WHITE);
  display.drawPixel(x+10,y+12,WHITE);  display.drawPixel(x+11,y+13,WHITE);  display.drawPixel(x+12,y+14,WHITE);  display.drawPixel(x+12,y+15,WHITE);  display.drawPixel(x+12,y+16,WHITE);  display.drawPixel(x+11,y+17,WHITE);  display.drawPixel(x+10,y+18,WHITE);  display.drawPixel(x+10,y+19,WHITE);  display.drawPixel(x+11,y+19,WHITE); display.drawPixel(x+12,y+19,WHITE);  display.drawPixel(x+13,y+19,WHITE);  display.drawPixel(x+13,y+18,WHITE);
}

void res(){  
  int x=20; /* variable locale pour controler la postion de la fonction  */
  display.drawRect(15,x+25,5,1,WHITE);  display.drawPixel(20,x+25,WHITE);  display.drawPixel(20,x+24,WHITE);  display.drawPixel(20,x+26,WHITE);  display.drawPixel(21,x+23,WHITE);  display.drawPixel(21,x+27,WHITE);  display.drawRect(22,x+22,3,1,WHITE);  display.drawRect(22,x+28,3,1,WHITE);  display.drawRect(25,x+27,16,1,WHITE);  display.drawRect(25,x+23,16,1,WHITE);  display.drawRect(41,x+22,3,1,WHITE);  display.drawRect(41,x+28,3,1,WHITE);  display.drawPixel(44,x+23,WHITE);  display.drawPixel(44,x+27,WHITE);  display.drawPixel(45,x+24,WHITE);  display.drawPixel(45,x+25,WHITE);  display.drawPixel(45,x+26,WHITE); display.drawRect(46,x+25,5,1,WHITE);  display.drawRect(28,x+24,2,3,WHITE);  display.drawRect(34,x+24,2,3,WHITE);
}

void rmnull()  /*fonction qui gère l'affichage quand la valeur de rm est nulle */
{
    display.setTextColor( WHITE );
    display.clearDisplay();
    display.setTextSize(1);
    display.setCursor(10,20);
    display.println("Veuillez inserer    une resistance");
    res();
    display.display(); 
    delay(1000);
}