HX711 easyC board I2C address selection and multi-board setup

Soldered_Bot · February 15, 2024, 9:41am

Customer:

I ordered several easyC-compatible boards but cannot find .ino sample code for I2C communication with the HX711 device. I found HX711 code but without easyC conversion. Can you help?

Originally submitted via email support on 15 February 2024. Migrated to the forum for community visibility.

Soldered_Bot · February 16, 2024, 6:49am

Soldered Support:

The code is in the library: GitHub - SolderedElectronics/Soldered-HX711-ADC-For-Weight-Scales-Arduino-Library · GitHub

Here’s an example of making a raw reading of the HX711 with easyC:

github.com/SolderedElectronics/Soldered-HX711-ADC-For-Weight-Scales-Arduino-Library

examples/easyCExample/easyCExample.ino

main

/**
 **************************************************
 *
 * @file        easyCExample.ino
 * @brief       Example for using the easyC variant of the HX711 breakout.
 *
 *              To successfully run the sketch:
 *              -Connect the breakout to your Dasduino board according to the diagrams below
 *              -Connect the load cell to the breakout
 *              -Open the Serial plotter at 115200 baud!
 *
 *              Load-cell amplifier HX711 board: solde.red/333005
 *              Dasduino Core: www.solde.red/333037
 *              Dasduino Connect: www.solde.red/333034
 *              Dasduino ConnectPlus: www.solde.red/333033
 *
 * @authors     Robert @ soldered.com
 ***************************************************/

// Include the library

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Soldered_Bot · February 16, 2024, 7:40am

Customer:

I will have 8 PCBs HX711 with easyC connected on the same bus. To select the right address, I need to initialize it with the following code and association table, correct?

// Init HX711
hx711.begin(xx); //where xx could be 0x30 -> 0x37

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Soldered_Bot · February 16, 2024, 7:48am

Soldered Support:

The table is correct. Here is a table for easyC from one of our libraries:

github.com/SolderedElectronics/Soldered-Hall-Effect-Sensor-Arduino-Library

examples/analogReadEasyC/analogReadEasyC.ino

a834924dc


      
          * @brief       Example of using the easyC Analog Hall Effect sensor by Soldered Electronics
          *              For more info, see: solde.red/333082
          *
          *
          * @copyright GNU General Public License v3.0
          * @authors Robert Soric for Soldered.com
          ***************************************************/
          
          #include "Hall-Effect-SOLDERED.h"
          
          // For this example, connect the Hall Effect Sensor to your Dasduino board via easyC
          // The default address is 0x30
          // You may change the address via the switches on the front of the board
          // In this table, 'x' represents a switch toggled 'UP'
          // Note that on the physical switches 1 and 3 are swapped
          // Address | 3 | 2 | 1 |
          // 0x30    |   |   |   |
          // 0x31    |   |   | x |
          // 0x32    |   | x |   |
          // 0x33    |   | x | x |
          // 0x34    | x |   |   |

The best way to be absolutely certain and avoid any errors is to use an I2C scanner sketch:

github.com/SolderedElectronics/Soldered-Hacky-Codes

I2C_Scanner/I2C_Scan/I2C_Scan.ino

main

// Include the standard I2C/Wire library
#include "Wire.h"

void setup()
{
    // Init Wire and Serial communications
    Wire.begin();
    Serial.begin(115200);

    // Print a welcome message to Serial
    Serial.println("\nSoldered I2C Scanner!");
    
}

void loop()
{
    // Create some helper variables for making the I2C requests
    byte error, address;
    int nDevices = 0; // Number of devices

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You can run this sketch on your main microcontroller and connect modules with different switches one by one and see which ones appear in the Serial monitor. When you connect an easyC module, it will print the address of that module so you can mark it.

Soldered_Bot · February 20, 2024, 12:35pm

Customer:

I get an error when uploading the sketch to the PCB: Property ‘upload.tool.serial’ is undefined. Do you have any suggestions?

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Soldered_Bot · February 21, 2024, 9:23am

Customer:

I get one data reading every 500mSec. Can I get it faster?

10:21:15.932 -> LOAD CELL : 2.11
10:21:16.489 -> LOAD CELL : 2.11
10:21:17.003 -> LOAD CELL : 1.06
10:21:17.520 -> LOAD CELL : 1.06
10:21:18.033 -> LOAD CELL : 1.06
10:21:18.593 -> LOAD CELL : 1.06
10:21:19.108 -> LOAD CELL : 1.06
10:21:19.622 -> LOAD CELL : 1.06
10:21:20.182 -> LOAD CELL : 1.06
10:21:20.697 -> LOAD CELL : 2.11
10:21:21.211 -> LOAD CELL : 2.11
10:21:21.729 -> LOAD CELL : 2.11
10:21:22.295 -> LOAD CELL : 1.06
10:21:22.815 -> LOAD CELL : 1.06
10:21:23.329 -> LOAD CELL : 1.06
10:21:23.843 -> LOAD CELL : 1.06
10:21:24.406 -> LOAD CELL : 0.00
10:21:24.918 -> LOAD CELL : 1.06
10:21:25.434 -> LOAD CELL : 1.06
10:21:25.949 -> LOAD CELL : 1.06
10:21:26.510 -> LOAD CELL : 0.00

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Soldered_Bot · February 21, 2024, 10:14am

Soldered Support:

Do you have a delay() in your sketch between readings? The easyC version gets data like this:

github.com/SolderedElectronics/Soldered-HX711-ADC-For-Weight-Scales-Arduino-Library

src/HX711-SOLDERED.cpp

75866bce6


      
                      filler = 0x00;
          
                  // Construct a 32-bit signed integer
                  value = (static_cast<unsigned long>(filler) << 24 | static_cast<unsigned long>(data[2]) << 16 |
                           static_cast<unsigned long>(data[1]) << 8 | static_cast<unsigned long>(data[0]));
          
                  return static_cast<long>(value);
              }
              else
              {
                  // Request the value over easyC and read it
                  uint8_t data[4];
                  readData((char *)data, 4);
          
                  // Assemble it back together in a long and return
                  long receivedData = ((long)data[0] << 24) | ((long)data[1] << 16) | ((long)data[2] << 8) | (long)data[3];
                  return receivedData;
              }
          }
          
          /**

It uses standard Wire functions, requestFrom and readBytes to get the data over I2C:

github.com/SolderedElectronics/Soldered-HX711-ADC-For-Weight-Scales-Arduino-Library

src/libs/Generic-easyC/easyC.hpp

75866bce6


      
          }

          

          /**

           * @brief           Private function to read n bytes over i2c

           *

           * @param  char a[] Array to read data to

           * @param  int n    Number of bytes to read

           *

           * @return int      Error code, always 0

           */

          int readData(char a[], int n)

          {

              Wire.requestFrom(address, n);

              Wire.readBytes(a, n);

          

              return 0;

          }

          

          /**

           * @brief                   Private function to send over i2c and then read n bytes

           *

If you have a delay() between readings remove it - that’s the fastest the easyC version can make the readings.

Soldered_Bot · February 21, 2024, 11:11am

Customer:

I tried the samples in your library and got the same result. I already removed all delays. The cycle time appears to depend on the firmware of the ATTINY404 that converts the HX711 protocol to the easyC (I2C) protocol. Before purchasing this board I was testing a simple HX711 without easyC directly connected to Arduino and got good results (100mSec per reading). I selected your product because I need to check 8 load cells almost simultaneously and very fast. What do you suggest? Is it possible to change the ATTINY404 firmware to speed up the communication?

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Soldered_Bot · February 21, 2024, 11:38am

Soldered Support:

Here’s the sketch of the ATTINY404 firmware on the device:

github.com/SolderedElectronics/Soldered-HX711-ADC-For-Weight-Scales-Arduino-Library

extras/attiny_firmware/attiny_firmware.ino

dev

/**
 **************************************************
 *
 * @file        Firmware for ATTINY on the HX711 easyC board
 * @brief       Communicates with the main board to send sensor data over easyC
 *

 *
 * @authors     Robert @ soldered.com
 ***************************************************/

#include "easyC.h"
#include <Wire.h>
#include "HX711-easyC-SOLDERED.h"

int addr = DEFAULT_ADDRESS;

// The variable where we periodically write the data to
long sensorData = 0;

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There don’t seem to be any delays or reasons why it would take a while - so the time is probably as quick as it can be for 8 devices on the I2C bus.

I can offer this possibility: if you try it, you do so at your own responsibility as it deviates from our design and requires a small modification on the board.

Here’s the datasheet for the load-cell amplifier:

Here’s the schematic of our board:

The board has a RATE pin. If this pin is connected to 5V it offers a faster reading rate. Check the datasheet, Table 1. I’d suggest trying this modification on one board first - if it’s fast enough, it might be worth doing to the others.

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