Use 6 x HX711 on arduino nano

Using Arduino Project Guidance
#1

Hi all,
I need some help with my project. I found the thread with 4 Hx711 and also the code from here

https://github.com/compugician/HX711-multi

I managed to read cels using only 4 HX711 but when i try with 6 i get only 0 on the output for all 6 channels.

this is my code:

#include "HX711-multi.h"

// Pins to the load cell amp
#define CLK 13      // clock pin to the load cell amp
#define DOUT1 A0    // data pin to the first lca
#define DOUT2 A1    // data pin to the second lca
#define DOUT3 A2    // data pin to the third lca
#define DOUT4 A3    // data pin to the third lca
#define DOUT5 A6    // data pin to the third lca
#define DOUT6 A7    // data pin to the third lca

#define BOOT_MESSAGE "MIT_ML_SCALE V0.8"

#define TARE_TIMEOUT_SECONDS 4

byte DOUTS[6] = {DOUT1, DOUT2, DOUT3, DOUT4, DOUT5, DOUT6};

#define CHANNEL_COUNT sizeof(DOUTS)/sizeof(byte)

long int results[CHANNEL_COUNT];

HX711MULTI scales(CHANNEL_COUNT, DOUTS, CLK);

void setup() {
  Serial.begin(115200);
  Serial.println(BOOT_MESSAGE);
  Serial.flush();
  pinMode(11,OUTPUT);
  
  tare();
}


void tare() {
  bool tareSuccessful = false;

  unsigned long tareStartTime = millis();
  while (!tareSuccessful && millis()<(tareStartTime+TARE_TIMEOUT_SECONDS*1000)) {
    tareSuccessful = scales.tare(20,10000);  //reject 'tare' if still ringing
  }
}

void sendRawData() {
  scales.read(results);
  for (int i=0; i<scales.get_count(); ++i) {;
    Serial.print( -results[i]);  
    Serial.print( (i!=scales.get_count()-1)?"\t":"\n");
  }  
  delay(10);
}

void loop() {
  
  sendRawData(); //this is for sending raw data, for where everything else is done in processing

  //on serial data (any data) re-tare
  if (Serial.available()>0) {
    while (Serial.available()) {
      Serial.read();
    }
    tare();
  }
 
}

Anyone has any ideea what i am doing wrong?

Thanks

#2

That library has some major flaws. pinMode() should NOT be called in a constructor, because there is no guarantee that the hardware is ready yet.

The library calls malloc() but does not check that malloc() succeeded. It simply assumes that it did.

Pins A6 and A7 on the nano are analog only. They can not be used as digital pins, which is what you are trying to do.

#3

Hi,
Thanks for the answer.

Is there any way / example to read these hx711 using same clock pin?

I tried now using D11 and D12 and get same result.

#4

Hi
did you manage to make it work ?
I am trying to do the same and want to know if this is can be done

#5