#include <Arduino.h>

#include "HX711.h"

#include <Wire.h>

#include <Adafruit_GFX.h>

#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128

#define SCREEN_HEIGHT 32

// HX711 circuit wiring

const int LOADCELL_DOUT_PIN = 11;

const int LOADCELL_SCK_PIN = 10;

#define OLED_RESET     -1

#define SCREEN_ADDRESS 0x3C

Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

HX711 scale;

void setup() {

  Serial.begin(9600);

  if(!display.begin(SSD1306_SWITCHCAPVCC, SCREEN_ADDRESS)) {

    Serial.println(F("SSD1306 allocation failed"));

    for(;;); // Don't proceed, loop forever

  }

  scale.begin(LOADCELL_DOUT_PIN, LOADCELL_SCK_PIN);

  display.display();

  delay(2000);

  display.clearDisplay();

  display.setTextSize(1);

  display.setTextColor(SSD1306_WHITE);

}

void loop() {

  if (scale.is_ready()) {

    display.clearDisplay();

    display.setCursor(0,0);

    display.display();

    scale.set_scale();    

    display.println("Tare... remove any weights from the scale.");

    display.display();

    delay(1000);

    scale.tare();

    display.println("Tare done...");

    display.print("Place a known weight on the scale...");

    display.display();

    delay(1000);

    display.clearDisplay();

    display.setCursor(0,0);

    display.display();

    long reading = scale.get_units(10);

    display.print("Result: ");

    display.println(reading);

    display.display();

  }

  else {

    display.println("HX711 not found.");

  }

  delay(5000);

}