/* Arduino code for a precision scale with a 1Kg load cell, HX711 ADC and mode selector
   Schematic: https://electronoobs.com/eng_arduino_tut115_sch1.php
   Code: https://electronoobs.com/eng_arduino_tut115_code1.php
   Video: https://youtu.be/LRd3W_p8PJ4 */
//https://how2electronics.com/weighing-machine-arduino-load-cell-hx711/

#include <Q2HX711.h>              //Downlaod from here: https://electronoobs.com/eng_arduino_hx711.php
#include <EEPROM.h>
#include <SPI.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

// Oled designation --------------------------------------------
#define OLED_ADDR 0x3C   // OLED i2c address
#define SCREEN_WIDTH 128 // OLED display width, in pixels (usually 128)
#define SCREEN_HEIGHT 64 // OLED display height, in pixels (64 for larger oLEDs)
#define OLED_RESET -1    // Reset pin gpio (or -1 if sharing Arduino reset pin)
#define SSD1306_NO_SPLASH
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);


#define DT 14
#define SCK 23
#define sw_pin 5

long sample = 0;
float val = 0;
long count = 0;

unsigned long readCount(void)
{
  unsigned long Count;
  unsigned char i;
  pinMode(DT, OUTPUT);
  digitalWrite(DT, HIGH);
  digitalWrite(SCK, LOW);
  Count = 0;
  pinMode(DT, INPUT);
  while (digitalRead(DT));
  for (i = 0; i < 24; i++)
  {
    digitalWrite(SCK, HIGH);
    Count = Count << 1;
    digitalWrite(SCK, LOW);
    if (digitalRead(DT))
      Count++;
  }
  digitalWrite(SCK, HIGH);
  Count = Count ^ 0x800000;
  digitalWrite(SCK, LOW);
  return (Count);
}

void setup()
{
  Serial.begin(115200);
  delay(500);



  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();
  display.setTextSize(1);
  display.setTextColor(SSD1306_WHITE);
  display.setCursor(30, 20);
  display.println(F("Teststation"));
  display.setCursor(25, 30);
  display.println(F("Software V1.0"));
  display.setCursor(0, 40);
  display.println(F("Code by Carlos Costa"));
  display.display();
  delay(1000);


  pinMode(SCK, OUTPUT);
  pinMode(sw_pin, INPUT_PULLUP);
  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.println(F(" Weight "));
  display.setCursor(0, 10);
  display.println(F(" Measurement "));
  display.display();
  delay(1000);

  //calibrate();
}

void loop()
{
  count = readCount();
  int w = (((count - sample) / val) - 2 * ((count - sample) / val));
  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.println(F("Measured Weight"));
  display.setCursor(0, 10);
  display.print(w);
  display.setCursor(50, 10);
  display.print("g ");
  display.display();

  if (!digitalRead(sw_pin) )
  {
    val = 0;
    sample = 0;
    w = 0;
    count = 0;
    calibrate();
  }
}

void calibrate()
{
  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.println(F("Calibrating..."));
  display.setCursor(0, 10);
  display.println(F("Please Wait..."));
  display.display();
  Serial.println("1");
  for (int i = 0; i < 100; i++)
  {
    count = readCount();
    sample += count;
    Serial.print(count);
  }
  Serial.println("2");
  sample /= 100;
  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.println(F("Put 100g & wait"));
  display.display();
  count = 0;
  while (count < 1000)
  {
    count = readCount();
    count = sample - count;
  }
  display.clearDisplay();
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.println(F("Please Wait...."));
  display.display();
  delay(2000);
  for (int i = 0; i < 100; i++)
  {
    count = readCount();
    val += sample - count;
  }
  val = val / 100.0;
  val = val / 100.0; // put here your calibrating weight
  //lcd.clear();
}