Arduino UNO High Precision Counting Scale

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Everyone needs a good scale in kitchen, what better than to build a high precision scale with the UNO?

Arduino UNO High Precision Counting Scale

Things used in this project

 

Hardware components

HARDWARE LIST
1 DFRobot Hx711 A/D converter
1 Arduino UNO
1 Load cell C3 class minimum
1 Adafruit Standard LCD - 16x2 White on Blue
1 Single Turn Potentiometer- 10k ohms
1 RFduino Battery Shield
1 Arduino Buzzer

Hand tools and fabrication machines

Soldering iron (generic)

 

Wood

 

Screws

Story

 

I've worked on scale words since 2015 but the biggest challenge has always been to build something that i repair every day at work. So i decided to try it, I had an arduino UNO, a load cell and an LCD. After a long run, I decided to rely on a DFrobot hx711. After a bit of study on how to connect the converter I started writing code for calibration and for counting scale mode function using the knowledge gained at work. Surprisingly I realized I could achieve a high level of precision despite using only a cheap converter and a C3 load cell. And so after a little bit of filtering here is my ArduScale 2.0! :) P.S. I have calibrated the scale with F1 class precision weights and it passed all metrological tests.

Code

 

Arduino uno scale test

Arduino

The main software is divided into two parts, weighing and counting function.
During the boot animation I entered a subroutine for the scale calibration function. The calibration data is stored in the Euprom of Arduino for subsequent uses.

CODE
#include "HX711.h"
#include"math.h"
#include <EEPROMex.h>
#include <EEPROMVar.h>
#include <LiquidCrystal.h>  
#define BUTTON 7 
#define LED 13 
#define TAREBUTTON 10
#define buzzer 8
// HX711.DOUT - pin #A2
// HX711.PD_SCK - pin #A3
LiquidCrystal lcd(12, 11, 5, 4, 3, 2); 

HX711 scale(A2, A3); // parameter "gain" is ommited; the default value 128 is used by the library

long somma1=0;
float I=0;
int a;
float b;
float calibval1;
float calibval2;
float media2=0;
float media1=0;
long somma2=0;
float pmax= 900;
int val=0;
int val1=0; //valore del pulsante di tara
float t =0;
float g=0;
void setup() {
  scale.set_scale();
  scale.tare();
  pinMode (buzzer, OUTPUT);
  tone(buzzer,440,1000);
  delay(500);
  noTone(buzzer);
  delay(200);
  tone (buzzer,330,1000);
  delay(1000);
  noTone(buzzer);
Serial.begin (9600);
  lcd.begin(16, 2); 
  lcd.print ("Fede Bil");
  lcd.setCursor( 0,1);
  lcd.print ("ver.1.0 :)");
   for (int positionCounter = 0; positionCounter < 6; positionCounter++) {
    // scroll one position left:
    lcd.scrollDisplayRight();
    // wait a bit:
    delay(450);} 
     for (int positionCounter = 0; positionCounter < 6; positionCounter++) {
    // scroll one position left:
    lcd.scrollDisplayLeft();
    // wait a bit:
    delay(450);}
  delay(3000);
  lcd.clear ();
  lcd.print ("Press Button 2");
  lcd.setCursor(0,1);
  lcd.print("to calibrate");
  delay(1500);
 pinMode(LED, OUTPUT); 
 pinMode (TAREBUTTON,OUTPUT); //IMPOSTA IL PULSANTE DI TARA
 pinMode(BUTTON, INPUT);     // imposta il pin digitale come input 
val=digitalRead (BUTTON);
if (val==HIGH){
  tone(buzzer,1047,1000);
digitalWrite(LED, HIGH);
calibrazione();}
else {
  tone(buzzer,660,500);
Serial.println (EEPROM.readFloat(10)); // restituisce il valore float memorizzato all'indirizzo indicato Ricarica calibval1
calibval2= (EEPROM.readFloat(10));
Serial.print ("calibval2=");
Serial.println (calibval2);
scale.set_scale (calibval2);
}}

void loop() {
 
pippo:  I= (scale.get_units(10));
Serial.println(I);
if (I < 1 &&I>0)
{ val1= digitalRead (TAREBUTTON);
if (val1==HIGH){
  tone(buzzer,622,1000);
  lcd.clear();
  lcd.print ("Tara");
  delay (1000);
  t= scale.get_units(10);
  g=round(t);
  scale.tare();}
  lcd.clear();
  lcd.print("d=0,5g");
  //lcd.setCursor(9,0);
 lcd.setCursor(0,1);
  lcd.print("0.00");
  lcd.setCursor(9,0);
  lcd.print ("d=0.2g");
  lcd.setCursor (9,1);
  lcd.print(I);
  delay(500);
  Serial.println ("0.00");
   val=digitalRead (BUTTON);
  if (val==HIGH){
  tone(buzzer,1047,500);
digitalWrite(LED, HIGH);
menu();}
else {
}
 goto pippo;
} 
val1= digitalRead (TAREBUTTON);
if (val1==HIGH){
  tone(buzzer,622,1000);
  lcd.clear();
  lcd.print ("Tara");
  delay (1000);
  t =scale.get_units(10);
   g=round(t);
  scale.tare();
 val=digitalRead (BUTTON); 
  if (val==HIGH){
  tone(buzzer,1047,500);
digitalWrite(LED, HIGH);
menu();}
else {
}}
  int c= (I*10);
  int e = (I*10);
 // e=round (c);
 int peso_div = (e+1)-((e+1)%2);
int  peso_div_5 = (c+2)-((c+2)%5);
  float f = (peso_div);
  float peso2 = (f/10);
   float d = (peso_div_5);
  float pesofin=(d/10);
   if (pesofin > pmax)
   {tone(buzzer,1047,2000);
     lcd.clear();
   lcd.print ("Overload");
    goto pippo;}
   lcd.clear();
   lcd.setCursor (0,0);
    lcd.print ("d=0,5g");
    lcd.setCursor(0, 1); 
    lcd.print (pesofin);
    lcd.setCursor(9,0);
    lcd.print ("d=0.2g");
    lcd.setCursor (9,1);
    lcd.print (peso2);
    delay(150);
    val=digitalRead (BUTTON);
if (val==HIGH){
  tone(buzzer,1047,500);
digitalWrite(LED, HIGH);
lcd.clear();
menu();}
else {
}
}

The article was first published in hackster, October 4, 2017

cr: https://www.hackster.io/Fedeasche/arduino-uno-high-precision-counting-scale-3f484b

author: Fedeasche

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