In order to come up with a working project, carry out the following steps:
A: Functional Check of HX711 Module
1. Build the following circuit to test that the HX711 Module is functional.
Figure-1: Test circuit for the functional check of HX711 Module
2. Upload the following sketch.
/* This program takes 10 samples from LC + HX711B at
1-sec interval and then computes the average.
unsigned long x = 0, y = 0;
unsigned long dataArray;
int j = 0;
pinMode(A1, INPUT); //data line //Yellow cable
pinMode(A0, OUTPUT); //SCK line //Orange cable
for (int j = 0; j < 10; j++)
digitalWrite(A0, LOW);//SCK is made LL
while (digitalRead(A1) != LOW) //wait until Data Line goes LOW
for (int i = 0; i < 24; i++) //read 24-bit data from HX711
clk(); //generate CLK pulse to get MSB-it at A1-pin
bitWrite(x, 0, digitalRead(A1));
x = x << 1;
clk(); //25th pulse
y = x;
x = 0;
dataArray[j] = y;
unsigned long sum = 0;
for (j = 0; j < 10; j++)
sum += dataArray[j];
Serial.print("Average Count = ");
sum = sum / 10;
3. Slowly vary the Pot-R3 and check that counts of the Serial Monitor changes. This is the end of the functional check of your HX711 Module.
B: Functional Check of Load Cell
1. Replace the resisitor based load cell of Fig-1 with the real Load Cell that you have. Be sure that the excitation terminals (E+, E-) of the HX711 Module are properly connected with the excitation terminals of the Load Cell; signal terminals (A+, A-) of the HX711 Module are properly connected with the signal terminals of the Load Cell.
Figure-2: Test circuit for the functional check of Load Cell
2. Change weight on the load cell and check that the count changes in the Serial Monitor.
C: Calibrating the Load Cell
D: Operational Check of the Load Cell