Arduino Based Digital Weight Scale

Arduino Based Weight Scale

This Simple project explains how to build a digital weight scale with Arduino.

A loadcell + HX711 module is used to measure the weight.

Using the arduino code we have to set a zero point after assembling the load cell mechanism.

A 16x2 LCD module is used to display the measured value in grams(g).

To improve the mobility of the scale, a rechargeable battery is used as the power source.

According to the requirement a necessary loadcell must be used.(In this project a 1Kg loadcell is used)

This digital scale is ideal for using in domestic areas for small weight measurements.

Tools & Components

1 X Arduino Nano

1 X Loadcell(1Kg) + HX711 Module

1 X 10K Ohm Potentiometer

1 X 16x2 LCD Module

1 X 5V Rechargeable battery pack

Suitable base arrangement for loadcell mounting

Breadboard

Connecting Wires

Connecting Components

HX711 DT Pin - Arduino Pin D02

HX711 SCK Pin - Arduino Pin D03

Loadcell Green wire - HX711 (A+) Pin

Loadcell White wire - HX711 (A-) Pin

LCD Module RS Pin – Arduino Pin A0

LCD Module EN Pin – Arduino Pin A1

LCD Module D4 Pin – Arduino Pin A2

LCD Module D5 Pin – Arduino Pin A3

LCD Module D6 Pin – Arduino Pin A4

LCD Module D7 Pin – Arduino Pin A5

LCD Module VEE Pin – Potentiometer Sig. Pin

Note : Assemble the loadcell in the correct direction(Up/Down).Readings will be incorrect if the loadcell mounted in upside down.

Mounting excessive load higher than the rated value of loadcell will damage the loadcell.Hence, always use a loadcell which rated higher value than the weight you intend to measure.(If you intend to measure small weights which will be in 1-1000g range , a 1Kg loadcell is suitable)

Arduino Code

//www.craftybin.blogspot.com
//Author : Chathura H.

#include "HX711.h"
const int LOADCELL_DOUT_PIN = 2;
const int LOADCELL_SCK_PIN = 3;
HX711 scale;

#include <LiquidCrystal.h>
const int rs = A0, en = A1, d4 = A2, d5 = A3, d6 = A4, d7 = A5;
LiquidCrystal lcd(A0, A1, A2, A3, A4 ,A5);

void setup()
{
  lcd.begin(16, 2);
  Serial.begin(9600);
  delay(100);

  Serial.println("Weight ");
  Serial.println("Measuring...");
  scale.begin(LOADCELL_DOUT_PIN, LOADCELL_SCK_PIN);
  scale.set_scale(2280.f);
  scale.tare();
 
  lcd.print("Insert Weight");
  delay(100);
  lcd.clear();
 }

void loop()
{
  Serial.print("one reading:\t");
  Serial.print(scale.get_units(), 1);
  Serial.print("\t| average:\t");
  Serial.println(scale.get_units(10), 1);
  scale.power_down();     
  delay(100);
  scale.power_up();

  lcd.print("Weight :");
  delay(100);
  lcd.clear();
  delay(1);
 
  lcd.print(scale.get_units());   
  lcd.print("g");
  delay(100);
  lcd.clear();
  delay(1);
}

Safety First !

Always Connect the power supply if you are absolutely sure that the components are connected correctly without changing polarity and short circuited the wiring.

Even if it seems nothing is wrong : DOUBLE CHECK EVERYTHING !!

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