// Forum: https://forum.arduino.cc/t/integrating-arduino-hx711-and-3-digit-7-segment-display/1167152
// This Wokwi project: https://wokwi.com/projects/375502753549598721
// Warning: full of bugs

#include <HX711.h>

// The used pins
const int DOUT = 32;
const int CLK = 30;

const int pinA = 2;
const int pinB = 3;
const int pinC = 4;
const int pinD = 5;
const int pinE = 6;
const int pinF = 7;
const int pinG = 8;
const int DIG1 = 10;
const int DIG2 = 11;
const int DIG3 = 12;

int time = 5;

HX711 scale;

float calibration_factor = 0; //Change this for calibration your load cell

float weight = 0.0;

unsigned long previousMillis;
const unsigned long interval = 500;

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

  pinMode(DIG1, OUTPUT);
  pinMode(DIG2, OUTPUT);
  pinMode(DIG3, OUTPUT);
  pinMode(pinA, OUTPUT);
  pinMode(pinB, OUTPUT);
  pinMode(pinC, OUTPUT);
  pinMode(pinD, OUTPUT);
  pinMode(pinE, OUTPUT);
  pinMode(pinF, OUTPUT);
  pinMode(pinG, OUTPUT);

  scale.begin(DOUT, CLK);
//  scale.set_scale();
//  scale.tare();             //Reset the scale to 0
}

void loop() 
{
  unsigned long currentMillis = millis();

  if( currentMillis - previousMillis >= interval)
  {
    previousMillis = currentMillis;

    // scale.set_scale(calibration_factor); //Adjust to this calibration factor
    weight = scale.get_units();
    Serial.println(weight, 1);
  }

  seven_segment((int)weight);
}

void choose_digit(char num) {
  switch (num) {
    default:
      // 0 default value
      digitalWrite(pinA, HIGH);
      digitalWrite(pinB, HIGH);
      digitalWrite(pinC, HIGH);
      digitalWrite(pinD, HIGH);
      digitalWrite(pinE, HIGH);
      digitalWrite(pinF, HIGH);
      digitalWrite(pinG, LOW);
      break;
    case 1:
      digitalWrite(pinA, LOW);
      digitalWrite(pinB, HIGH);
      digitalWrite(pinC, HIGH);
      digitalWrite(pinD, LOW);
      digitalWrite(pinE, LOW);
      digitalWrite(pinF, LOW);
      digitalWrite(pinG, LOW);
      break;
    case 2:
      digitalWrite(pinA, HIGH);
      digitalWrite(pinB, HIGH);
      digitalWrite(pinC, LOW);
      digitalWrite(pinD, HIGH);
      digitalWrite(pinE, HIGH);
      digitalWrite(pinF, LOW);
      digitalWrite(pinG, HIGH);
      break;
    case 3:
      digitalWrite(pinA, HIGH);
      digitalWrite(pinB, HIGH);
      digitalWrite(pinC, HIGH);
      digitalWrite(pinD, HIGH);
      digitalWrite(pinE, LOW);
      digitalWrite(pinF, LOW);
      digitalWrite(pinG, HIGH);
      break;
    case 4:
      digitalWrite(pinA, LOW);
      digitalWrite(pinB, HIGH);
      digitalWrite(pinC, HIGH);
      digitalWrite(pinD, LOW);
      digitalWrite(pinE, LOW);
      digitalWrite(pinF, HIGH);
      digitalWrite(pinG, HIGH);
      break;
    case 5:
      digitalWrite(pinA, HIGH);
      digitalWrite(pinB, LOW);
      digitalWrite(pinC, HIGH);
      digitalWrite(pinD, HIGH);
      digitalWrite(pinE, LOW);
      digitalWrite(pinF, HIGH);
      digitalWrite(pinG, HIGH);
      break;
    case 6:
      digitalWrite(pinA, HIGH);
      digitalWrite(pinB, LOW);
      digitalWrite(pinC, HIGH);
      digitalWrite(pinD, HIGH);
      digitalWrite(pinE, HIGH);
      digitalWrite(pinF, HIGH);
      digitalWrite(pinG, HIGH);
      break;
    case 7:
      digitalWrite(pinA, HIGH);
      digitalWrite(pinB, HIGH);
      digitalWrite(pinC, HIGH);
      digitalWrite(pinD, LOW);
      digitalWrite(pinE, LOW);
      digitalWrite(pinF, LOW);
      digitalWrite(pinG, LOW);
      break;
    case 8:
      digitalWrite(pinA, HIGH);
      digitalWrite(pinB, HIGH);
      digitalWrite(pinC, HIGH);
      digitalWrite(pinD, HIGH);
      digitalWrite(pinE, HIGH);
      digitalWrite(pinF, HIGH);
      digitalWrite(pinG, HIGH);
      break;
    case 9:
      digitalWrite(pinA, HIGH);
      digitalWrite(pinB, HIGH);
      digitalWrite(pinC, HIGH);
      digitalWrite(pinD, HIGH);
      digitalWrite(pinE, LOW);
      digitalWrite(pinF, HIGH);
      digitalWrite(pinG, HIGH);
      break;
  }
}

void pick_digit(int digit) {
  digitalWrite(DIG1, HIGH);
  digitalWrite(DIG2, HIGH);
  digitalWrite(DIG3, HIGH);

  switch (digit) {
    case 1: 
      digitalWrite(DIG1, LOW); 
      break;
    case 2: 
      digitalWrite(DIG2, LOW); 
      break;
    default: 
      digitalWrite(DIG3, LOW); 
      break;
  }
}

void seven_segment(int number) {
  unsigned char hundreds = int (number / 100);
  unsigned char tens     = int ((number / 10) % 10);
  unsigned char ones     = int (number % 10);

  //123
  choose_digit(hundreds);
  pick_digit(1);
  delay(time);

  choose_digit(tens);
  pick_digit(2);
  delay(time);

  choose_digit(ones);
  pick_digit(3);
  delay(time);
}