Another HX711 which outputs only 0

Hi Community!

I’m trying to build a scale as a prototype for a little project. I’m basically following this guide:
https://learn.sparkfun.com/tutorials/load-cell-amplifier-hx711-breakout-hookup-guide/all

I have an arduino rev3, a SparkFun’s HX711 load cell amp and a 500g load cell (4 wires). I also shorted the VCC and VDD pins together.
This is a picture of how everything is setup:

The only output I get is 0g.

Can anyone help me troubleshoot this? What should I do?

Here is the code used:

/*
 Example using the SparkFun HX711 breakout board with a scale
 By: Nathan Seidle
 SparkFun Electronics
 Date: November 19th, 2014
 License: This code is public domain but you buy me a beer if you use this and we meet someday (Beerware license).
 
 This is the calibration sketch. Use it to determine the calibration_factor that the main example uses. It also
 outputs the zero_factor useful for projects that have a permanent mass on the scale in between power cycles.
 
 Setup your scale and start the sketch WITHOUT a weight on the scale
 Once readings are displayed place the weight on the scale
 Press +/- or a/z to adjust the calibration_factor until the output readings match the known weight
 Use this calibration_factor on the example sketch
 
 This example assumes pounds (lbs). If you prefer kilograms, change the Serial.print(" lbs"); line to kg. The
 calibration factor will be significantly different but it will be linearly related to lbs (1 lbs = 0.453592 kg).
 
 Your calibration factor may be very positive or very negative. It all depends on the setup of your scale system
 and the direction the sensors deflect from zero state

 This example code uses bogde's excellent library: https://github.com/bogde/HX711
 bogde's library is released under a GNU GENERAL PUBLIC LICENSE

 Arduino pin 2 -> HX711 CLK
 3 -> DOUT
 5V -> VCC
 GND -> GND
 
 Most any pin on the Arduino Uno will be compatible with DOUT/CLK.
 
 The HX711 board can be powered from 2.7V to 5V so the Arduino 5V power should be fine.
 
*/

#include "HX711.h" //This library can be obtained here http://librarymanager/All#Avia_HX711

#define LOADCELL_DOUT_PIN  3
#define LOADCELL_SCK_PIN  2

HX711 scale;

float calibration_factor = 1; //-7050 worked for my 440lb max scale setup

void setup() {
  Serial.begin(9600);
  Serial.println("HX711 calibration sketch");
  Serial.println("Remove all weight from scale");
  Serial.println("After readings begin, place known weight on scale");
  Serial.println("Press + or a to increase calibration factor");
  Serial.println("Press - or z to decrease calibration factor");
  Serial.println("Loop begins in 5 seconds");
  delay(5000);

  scale.begin(LOADCELL_DOUT_PIN,LOADCELL_SCK_PIN);
  scale.set_scale();
  scale.tare();	//Reset the scale to 0

  long zero_factor = scale.read_average(); //Get a baseline reading
  Serial.print("Zero factor: "); //This can be used to remove the need to tare the scale. Useful in permanent scale projects.
  Serial.println(zero_factor);
}

void loop() {

  scale.set_scale(calibration_factor); //Adjust to this calibration factor

  Serial.print("Reading: ");
  Serial.print(scale.get_units(), 10);
  Serial.print("g"); //Change this to kg and re-adjust the calibration factor if you follow SI units like a sane person
  Serial.print(" calibration_factor: ");
  Serial.print(calibration_factor);
  Serial.println();

  if(Serial.available())
  {
    char temp = Serial.read();
    if(temp == '+' || temp == 'a')
      calibration_factor += 10;
    else if(temp == '-' || temp == 'z')
      calibration_factor -= 10;
  }
}

It looks like the arduino side yellow & black (Dat & CLK) are in the wrong pin #'s…hard to tell, but counting the holes it looks like DAT is in #4 and I can’t tell where the Black one goes

Swap to match this Load Cell Amplifier HX711 Breakout Hookup Guide - SparkFun Learn and see how that goes

I confirm CLK is connected ton pin#2 and DAT to pin #3

This is what I get:
Arduino_IDE_mFUqIs7nHP

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VCC vs VDD: VCC is the main supply voltage, while VDD sets the digital logic voltage reference and should be connected to microcontroller supply voltage, or shorted to VCC.

VCC and VDD on the HX711 are shorted together. The red wire is connected to 5v pin.

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Might be a bad HX711 in that case.
https://www.sparkfun.com/returns

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Is there any other test I could do to make sure all the things are wired correctly like measuring voltage betweens pins?

I’d try a different, known good load cell. Best choice would be one already working on a HX711.

Also, clean the flux off the connections on the board, that will definitely give you trouble. Try that first, if you’re lucky that will correct your trouble.

Which make/model load cell?
That blue wire is throwing me off.

Ideally, you’d test load cell independently from the instrumentation (the HX711). Connect a power supply to the Excitation and measure millivolts on the signals. Since this one is already soldered, at least make sure you get a few millivolts on the signal wires when you flex the beam for a few hundred grams-force and that it returns to about zero when unloaded.