// choose if digital font "7-segment" be used for the Timer
//#define DIGITAL_FONT

#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>
#include <EEPROM.h>

#ifdef DIGITAL_FONT
  #include "Numbers.h"
  //#include "digital24B.h"
  #define font1 &DS_DIGIB24pt7b
#else
  #include <Fonts/FreeSansBold18pt7b.h>
  #define font1 &FreeSansBold18pt7b
#endif

#include <Fonts/FreeSans9pt7b.h>
#define font2 &FreeSans9pt7b
#define font3 &FreeSans9pt7b



#define SCREEN_WIDTH 128     // OLED display width, in pixels
#define SCREEN_HEIGHT 64     // OLED display height, in pixels
#define OLED_RESET -1        // Reset pin # (or -1 if sharing Arduino reset pin)
#define SCREEN_ADDRESS 0x3C  ///< See datasheet for Address; 0x3D for 128x64, 0x3C for 128x32
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);


#define impactPin A0
#define BTN1 2
#define elapsedTime (millis() - tNow)
#define buttonPressed !digitalRead(BTN_SELECT)

unsigned long tNow;
//************************************************************
//********************* SETUP ********************************
//************************************************************
void setup() {
  
  pinMode(BTN1, INPUT_PULLUP);
  initializeDisplay();
  tNow = millis();
  analogReference(INTERNAL);

}
//************************************************************
//********************** LOOP  *******************************
//************************************************************
float v;
int vd ;
void loop() {
  vd = analogRead(impactPin);
  v = vd * 1.1/1024;
  displayV();

  delay(1000);
}


//************************************************************
//****************** Initialze DISPLAY ***********************
//************************************************************
void initializeDisplay() {
  if (!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {
    Serial.println(F("SSD1306 allocation failed"));
  }

  display.clearDisplay();

  //display.setTextSize(1);  // Draw 2X-scale text
  display.setRotation(2);
  display.setTextColor(SSD1306_INVERSE);
  display.setFont(font1);
  display.display();

}


//************************************************************
//************* Display Count Down Time **********************
//************************************************************
void displayV() {
    display.clearDisplay();
    display.setFont(font1);
    display.setCursor(30, 40);
    //display.println(vd);
    display.println(v);
    display.display();
}