Electronic Weighing Machine

1/*
2 * https://facebook/nissiembeddedlab
3 * 2018 September 4
4  * 3 Kg Load Cell HX711 Module Interface with Arduino to measure weight in Kgs
5  Arduino  pin  2 -> HX711 CLK 3 -> DOUT 5V -> VCC GND -> GND
6*/
7
8#include  "HX711.h"  
9#define DOUT  3
10#define CLK  2
11
12HX711 scale(DOUT, CLK);
13#include  <Wire.h>
14#include <LiquidCrystal_PCF8574.h>
15
16LiquidCrystal_PCF8574 lcd(0x3F);
17float  calibration_factor = -96650;
18const int SW = 7;
19void setup() 
20{
21  Wire.begin();
22  Wire.beginTransmission(0x3F);
23  pinMode(SW, INPUT_PULLUP);
24  lcd.setBacklight(255);
25  lcd.begin(16, 2);
26  lcd.setCursor(0,0);
27  lcd.print("Nissi 3kgLoadCell");
28  lcd.setCursor(0,1);
29  lcd.print("Press Sw to tare");
30  scale.set_scale(-849650);  
31  scale.tare();           
32}
33void loop() 
34{
35  lcd.setCursor(0,1);
36  lcd.print("W =  ");
37  lcd.setCursor(6,1);
38  lcd.print(scale.get_units(),3);  
39  lcd.println(" kg   ");
40  int x = digitalRead(SW);
41  if(x == LOW)
42  {
43      scale.tare();  
44  }
45}
46