basic LCD scale using load cell and hx711

loadcell.ino

//Sample using LiquidCrystal library
#include <LiquidCrystal.h>

/*******************************************************

This program will test the LCD panel and the buttons
Mark Bramwell, July 2010

********************************************************/

// select the pins used on the LCD panel
LiquidCrystal lcd(8, 9, 4, 5, 6, 7);

// define some values used by the panel and buttons
int lcd_key     = 0;
int adc_key_in  = 0;
#define btnRIGHT  0
#define btnUP     1
#define btnDOWN   2
#define btnLEFT   3
#define btnSELECT 4
#define btnNONE   5

#include <HX711_ADC.h>
#include <EEPROM.h>

//HX711 constructor (dout pin, sck pin):
HX711_ADC LoadCell(2, 3);

const int eepromAdress = 0;

long t;


// read the buttons
int read_LCD_buttons()
{
 adc_key_in = analogRead(0);      // read the value from the sensor
 // my buttons when read are centered at these valies: 0, 144, 329, 504, 741
 // we add approx 50 to those values and check to see if we are close
 if (adc_key_in > 1000) return btnNONE; // We make this the 1st option for speed reasons since it will be the most likely result
 // For V1.1 us this threshold
 if (adc_key_in < 50)   return btnRIGHT;
 if (adc_key_in < 250)  return btnUP;
 if (adc_key_in < 450)  return btnDOWN;
 if (adc_key_in < 650)  return btnLEFT;
 if (adc_key_in < 850)  return btnSELECT;

 // For V1.0 comment the other threshold and use the one below:
/*
 if (adc_key_in < 50)   return btnRIGHT;
 if (adc_key_in < 195)  return btnUP;
 if (adc_key_in < 380)  return btnDOWN;
 if (adc_key_in < 555)  return btnLEFT;
 if (adc_key_in < 790)  return btnSELECT;
*/


 return btnNONE;  // when all others fail, return this...
}

void setup()
{
  float calValue; // calibration value
  calValue = 696.0; // uncomment this if you want to set this value in the sketch 
 lcd.begin(16, 2);              // start the library
 lcd.setCursor(0,0);
// lcd.print("Push the buttons"); // print a simple message

 LoadCell.begin();
  long stabilisingtime = 2000; // tare preciscion can be improved by adding a few seconds of stabilising time
  LoadCell.start(stabilisingtime);
  if(LoadCell.getTareTimeoutFlag()) {
    Serial.println("Tare timeout, check MCU>HX711 wiring and pin designations");
  }
  else {
    LoadCell.setCalFactor(calValue); // set calibration value (float)
    Serial.println("Startup + tare is complete");
  }
}

void loop()
{
    //update() should be called at least as often as HX711 sample rate; >10Hz@10SPS, >80Hz@80SPS
  //use of delay in sketch will reduce effective sample rate (be carefull with use of delay() in the loop)
  LoadCell.update();

  //get smoothed value from data set
  if (millis() > t + 250) {
    float i = LoadCell.getData();
    Serial.print("Load_cell output val: ");
    Serial.println(i);
    t = millis();
  }

  
 //lcd.setCursor(9,1);            // move cursor to second line "1" and 9 spaces over
 //lcd.print(millis()/1000);      // display seconds elapsed since power-up


 lcd.setCursor(0,0);            // move to the begining of the first line

 if (millis() > t + 250) {
    float i = LoadCell.getData();
    Serial.print("Load_cell output val: ");
    Serial.println(i);
    lcd.setCursor(0,0);lcd.print("          ");
    lcd.setCursor(0,0);            // move to the begining of the first line
    lcd.print(i);
    t = millis();
  }


 
 lcd_key = read_LCD_buttons();  // read the buttons
 lcd.setCursor(0,1);            // move to the begining of the first line

 switch (lcd_key)               // depending on which button was pushed, we perform an action
 {
   case btnRIGHT:
     {
     lcd.print("RIGHT ");
     break;
     }
   case btnLEFT:
     {
     lcd.print("LEFT   ");
     break;
     }
   case btnUP:
     {
     lcd.print("UP    ");
     break;
     }
   case btnDOWN:
     {
     lcd.print("DOWN  ");
     break;
     }
   case btnSELECT:
     {
     lcd.print("TARE");
      LoadCell.tareNoDelay();
      while (LoadCell.getTareStatus() != true) {
        delay(250);
      }
      Serial.println("Tare complete");
       lcd.setCursor(0,1);            // move to the begining of the first line
      lcd.print("    ");
     break;
     }
     case btnNONE:
     {
     //lcd.print("NONE  ");
     break;
     }
 }

}