Weight scale by Konstantinos Anastasakis https://github.com/kon-anast/kan-weight_scale
My blog https://kostislab.blogspot.gr/

This is a weight scale program for Arduino with a HX711 module

Components needed:
-Arduino board (I use arduino pro mmini 3.3v)
-Scale sensor (I got it from a broken kitchen scale)
-HX711 module
-Potentiometer
-LCD 1602 module (in advance use  also an i2c module)
-Battery
-Switches

if there is noise from the sensor use two 0.1uf capacitors to
filter the signal from the Scale sensor

Setup your scale and start WITHOUT a weight on the scale
Once readings are displayed place a known weight on the scale
Αdjust the calibration_factor with the potentiometer until the
output readings match the known weight


---CONNECTIONS---
HX711 connection
  *The HX711 board can be powered from 2.7V to 5V.
  Arduino pin D6 -> HX711 CLK
  Arduino pin D5 -> HX711 DOUT
  Arduino pin 5V -> HX711 VCC
  Arduino pin GND -> HX711 GND

Sensor connection
  Excitation+ (E+) or VCC is red
  Excitation- (E-) or ground is black.
  Output+ (O+), Signal+ (S+)+ or Amplifier+ (A+) is white
  O-, S-, or A- is green or blue
  more info hire:
  https://learn.sparkfun.com/tutorials/load-cell-amplifier-hx711-breakout-hookup-guide

LCD display connection
  With I2C adapter check your board to find the SCK and SDA pins.
  more info hire: https://arduino-info.wikispaces.com/LCD-Blue-I2C
  Set the LCD address to 0x27 for a 16 chars 2 line display. A FEW use address 0x3F.
  ​Some of I2C LCD interfaces have pins (or solder pads) that can be changed to change
  the address. They are usually labelled as A0-A1-A2. Here's how the address change
  from a default 0x27 or 0x3F, if you connect the address pads together.
  A0	A1	A2	HEX Address (1 = Not Connected. 0 = Connected):
  1	1	1	0x27
  0	1	1	0x26
  1	0	1	0x25
  0	0	1	0x24
  1	1	0	0x23
  0	1	0	0x22
  1	0	0	0x21
  0	0	0	0x20

  If no i2c adapter the connections will be:
  * LCD RS pin to digital pin 12
  * LCD Enable pin to digital pin 11
  * LCD D4 pin to digital pin 5
  * LCD D5 pin to digital pin 4
  * LCD D6 pin to digital pin 3
  * LCD D7 pin to digital pin 2
  * LCD R/W pin to ground
  * LCD VSS pin to ground
  * LCD VCC pin to 5V
  * 10K resistor:
  * ends to +5V and ground
  * wiper to LCD VO pin (pin 3)

Potentiometer connection
  GND, A2, VCC

Calibration, Zero and Memory Button connection
  D10,  D11,  D12 *All to GND, it will be LOW when pressed.

Battery monitor
  To create voltage divider connect two resistors to A0 pin
  R1 10k to GND and A0
  R2 25k - 75k to battery + and A0
  more info hire: https://playground.arduino.cc/Main/DirectMathVoltmeter
  and 

Timer DS3231 module
  Future plans is to put a timer with a beeper, so I don't burn the food...
  maybe a bluetooth and esp also... :)

Soft power on
  Not completed yet needs more work...