Is this circuit right according to the diagram?

Other Hardware General Electronics
1

Hey guys,

I am new to circuitry and I need help verifying if my circuit is right according to a wiring diagram. The circuit is for a weight scale with the HX711 ADC amplifier.
Please refer to the following link for the project on Instructables. Please see the attached schematic and code that allows one to calibrate the sensor. I am supposed to get a relevant weight reading but all I get are zeros :frowning: . At this stage, I load the sensor with a known weight, and all i get is zeros.

I've posted this before, however i was advised to re-submit with a schematic of what I did.

I am unfortunately a noob at this, but hoping I can get some help and advice from experts like you all.
Kind Regards
V

/*
 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
 Arduino pin 6 -> HX711 CLK
 Arduino pin 5 -> HX711 DOUT
 Arduino pin 5V -> HX711 VCC
 Arduino pin GND -> HX711 GND
*/

#include "HX711.h"

HX711 scale(5, 6);

float calibration_factor = 48100; // this calibration factor is adjusted according to my load cell
float units;
float ounces;

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");

  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: ");
  units = scale.get_units(), 10;
  if (units < 0)
  {
    units = 0.00;
  }
  ounces = units * 0.035274;
  Serial.print(units);
  Serial.print(" kg");
  Serial.print(" calibration_factor: ");
  Serial.print(calibration_factor);
  Serial.println();
  delay(500);

  if(Serial.available())
  {
    char temp = Serial.read();
    if(temp == '+' || temp == 'a')
      calibration_factor += 1;
    else if(temp == '-' || temp == 'z')
      calibration_factor -= 1;
  }
}

Schematic.png
Schematic.png777×1600 133 KB

2

OP's picture:

Schematic.png
Schematic.png777×1600 133 KB

(See the image guide to find out how I did this.)

It is better to use the library's begin() method instead of setting the pins in the constructor.

HX711 scale(5, 6);

HX711 scale;
void setup() {
  scale.begin(5,6);
  ....

The next time you draw a schematic, try to draw it without the breadboard. Just show what is connected to what, not where the wires run across the desk or what color they are.

I use the HX711 a lot but I don't use those 3-wire strain gauges. Only 4-wire. So I will have to take your word for it that you wired it correctly.