Using HX711 for Weight Measurement

Table of Contents

1. Introduction to HX711

2. Module Operating Principle

3. Code Implementation

4. Conclusion

—

Introduction to HX711

Kimi, start!

In summary, HX711 is essentially an ADC.

—

Module Operating Principle

The internal structure diagram of HX711 is as follows:

The working principle of HX711 is as follows:

Inside HX711, there is a controller, and during use, the MCU pins receive data in a timed sequence.

—

Code Implementation

（1）hx711.h

#ifndef _HX711_H_
#define _HX711_H_

#include "reg52.h"
#include "intrins.h"
#define HX711_DATA  P10 // Assume connected to P1.0
#define HX711_CLK   P11 // Assume connected to P1.1

unsigned long Read_HX711(void);
unsigned long Get_weight(void);
unsigned long Get_1kg_weight(void);
void delay_ms(unsigned char ms);
void delay_us(unsigned char us);

#endif

（2）hx711.c

#include "hx711.h"
 
unsigned int weight_1kg = 0;

void delay_ms(unsigned char ms)
{
 {
  unsigned char i, j;
  _nop_();
  _nop_();
  _nop_();
  i = 11;
  j = 190;
do
  {
   while (--j);
  } while (--i);
 }while(ms--);
}


void delay_us(unsigned char us)
{
 {
  _nop_();
  _nop_();
 }while(us--);
}


unsigned long Get_1kg_weight(void) // Call this function after placing a 1 kg object on the platform
{
 weight_1kg =  Read_HX711();
return weight_1kg;
}

unsigned long Get_weight(void)
{
 unsigned int weight = 0;
 weight = Read_HX711();
 weight /= weight_1kg;
return weight;
}

unsigned long Read_HX711(void) // CLK is 25, input channel A
{
    unsigned long count;
    unsigned char i;

    HX711_CLK = 0;
    count = 0;

    while(HX711_DATA);  // Wait for DATA to go low

    for (i = 0; i < 24; i++) {
        HX711_CLK = 1;   // CLK goes high, ready to read data bit
        count = count << 1;  // Shift left by one bit to make room for the next data bit
        HX711_CLK = 0;   // CLK goes low, actually read data bit on the rising edge

        if (HX711_DATA)
            count++;
    }

    HX711_CLK = 1;     // Send an extra pulse to set the gain for the next read
    count = count ^ 0x800000; // Can convert to negative if needed
    HX711_CLK = 0;

    return (count);
}

void main(void) {
    unsigned long weight;

    // Perform any necessary initialization
    // ...

    while(1) {
        weight = Read_HX711();
        // Use the read weight value
        // ...
    }
}

First call the Get_1kg_weight function, then call the Get_weight function.

—

Conclusion

Using HX711 is quite simple, mainly focusing on the output of the measurement completion signal.

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