/*
  Example using the SparkFun HX711 breakout board with a scale
  By: Nathan Seidle
  SparkFun Electronics
  Date: November 19th, 2014
  License: This code is public domain but you buy me a beer if you use this and we meet someday (Beerware license).

  This example demonstrates basic scale output. See the calibration sketch to get the calibration_factor for your
  specific load cell setup.

  This example code uses bogde's excellent library:"https://github.com/bogde/HX711"
  bogde's library is released under a GNU GENERAL PUBLIC LICENSE

  The HX711 does one thing well: read load cells. The breakout board is compatible with any wheat-stone bridge
  based load cell which should allow a user to measure everything from a few grams to tens of tons.
  Arduino pin 2 -> HX711 CLK
  3 -> DAT
  5V -> VCC
  GND -> GND

  The HX711 board can be powered from 2.7V to 5V so the Arduino 5V power should be fine.

*/

#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)
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

#include "HX711.h"

#define calibration_factor 190.5 //This value is obtained using the SparkFun_HX711_Calibration sketch

#define LOADCELL_DOUT_PIN  3
#define LOADCELL_SCK_PIN  2

HX711 scale;

int loadCellValue = 1;

void setup() {
  Serial.begin(9600);
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.clearDisplay();

  display.setTextSize(2.5);
  display.setTextColor(WHITE);
  display.setCursor(20, 20);
  // Display static text
  display.println("Hi Wendy");
  display.display();

  delay(2000);

  scale.begin(LOADCELL_DOUT_PIN, LOADCELL_SCK_PIN);
  scale.set_scale(calibration_factor); //This value is obtained by using the SparkFun_HX711_Calibration sketch
  scale.tare(); //Assuming there is no weight on the scale at start up, reset the scale to 0

  display.clearDisplay();
  display.setTextSize(2.5);
  display.setTextColor(WHITE);
  display.setCursor(20, 20);
  // Display static text
  display.println("READY");
  display.display();

  delay(500);
}

void loop() {

  loadCellValue = scale.get_units(5); // Take reading from scale

  display.clearDisplay();
  display.setTextSize(3.5);
  display.setTextColor(WHITE);
  display.setCursor(10,20); 
  //display.print(loadCellValue);
  display.print(scale.get_units(5));
  display.display();
  //Serial.print("Reading: ");
  Serial.print(scale.get_units(5)); //scale.get_units() returns a float
  //Serial.print(" lbs"); //You can change this to kg but  you'll need to refactor the calibration_factor
  Serial.println();
}