HX711 amplifier

/*

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HX711_ADC

Arduino library for HX711 24-Bit Analog-to-Digital Converter for Weight Scales

Olav Kallhovd sept2017

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*/

/*

This example file shows how to calibrate the load cell and optionally store the calibration

value in EEPROM, and also how to change the value manually.

The result value can then later be included in your project sketch or fetched from EEPROM.

To implement calibration in your project sketch the simplified procedure is as follow:

LoadCell.tare();

//place known mass

LoadCell.refreshDataSet();

float newCalibrationValue = LoadCell.getNewCalibration(known_mass);

*/

#include <HX711_ADC.h>

#if defined(ESP8266)|| defined(ESP32) || defined(AVR)

#include <EEPROM.h>

#endif

//pins:

const int HX711_dout = 4; //mcu > HX711 dout pin

const int HX711_sck = 5; //mcu > HX711 sck pin

//HX711 constructor:

HX711_ADC LoadCell(HX711_dout, HX711_sck);

const int calVal_eepromAdress = 0;

unsigned long t = 0;

void setup() {

Serial.begin(57600); delay(10);

Serial.println();

Serial.println("Starting...");

LoadCell.begin();

//LoadCell.setReverseOutput(); //uncomment to turn a negative output value to positive

unsigned long stabilizingtime = 2000; // preciscion right after power-up can be improved by adding a few seconds of stabilizing time

boolean _tare = true; //set this to false if you don't want tare to be performed in the next step

LoadCell.start(stabilizingtime, _tare);

if (LoadCell.getTareTimeoutFlag() || LoadCell.getSignalTimeoutFlag()) {

Serial.println("Timeout, check MCU>HX711 wiring and pin designations");

while (1);

}

else {

LoadCell.setCalFactor(1.0); // user set calibration value (float), initial value 1.0 may be used for this sketch

Serial.println("Startup is complete");

}

while (!LoadCell.update());

calibrate(); //start calibration procedure

}

void loop() {

static boolean newDataReady = 0;

const int serialPrintInterval = 0; //increase value to slow down serial print activity

// check for new data/start next conversion:

if (LoadCell.update()) newDataReady = true;

// get smoothed value from the dataset:

if (newDataReady) {

if (millis() > t + serialPrintInterval) {

float i = LoadCell.getData();

Serial.print("Load_cell output val: ");

Serial.println(i);

newDataReady = 0;

t = millis();

}

}

// receive command from serial terminal

if (Serial.available() > 0) {

char inByte = Serial.read();

if (inByte == 't') LoadCell.tareNoDelay(); //tare

else if (inByte == 'r') calibrate(); //calibrate

else if (inByte == 'c') changeSavedCalFactor(); //edit calibration value manually

}

// check if last tare operation is complete

if (LoadCell.getTareStatus() == true) {

Serial.println("Tare complete");

}

}

void calibrate() {

Serial.println("***");

Serial.println("Start calibration:");

Serial.println("Place the load cell an a level stable surface.");

Serial.println("Remove any load applied to the load cell.");

Serial.println("Send 't' from serial monitor to set the tare offset.");

boolean _resume = false;

while (_resume == false) {

LoadCell.update();

if (Serial.available() > 0) {

if (Serial.available() > 0) {

char inByte = Serial.read();

if (inByte == 't') LoadCell.tareNoDelay();

}

}

if (LoadCell.getTareStatus() == true) {

Serial.println("Tare complete");

_resume = true;

}

}

Serial.println("Now, place your known mass on the loadcell.");

Serial.println("Then send the weight of this mass (i.e. 100.0) from serial monitor.");

float known_mass = 0;

_resume = false;

while (_resume == false) {

LoadCell.update();

if (Serial.available() > 0) {

known_mass = Serial.parseFloat();

if (known_mass != 0) {

Serial.print("Known mass is: ");

Serial.println(known_mass);

_resume = true;

}

}

}

LoadCell.refreshDataSet(); //refresh the dataset to be sure that the known mass is measured correct

float newCalibrationValue = LoadCell.getNewCalibration(known_mass); //get the new calibration value

Serial.print("New calibration value has been set to: ");

Serial.print(newCalibrationValue);

Serial.println(", use this as calibration value (calFactor) in your project sketch.");

Serial.print("Save this value to EEPROM adress ");

Serial.print(calVal_eepromAdress);

Serial.println("? y/n");

_resume = false;

while (_resume == false) {

if (Serial.available() > 0) {

char inByte = Serial.read();

if (inByte == 'y') {

#if defined(ESP8266)|| defined(ESP32)

EEPROM.begin(512);

#endif

EEPROM.put(calVal_eepromAdress, newCalibrationValue);

#if defined(ESP8266)|| defined(ESP32)

EEPROM.commit();

#endif

EEPROM.get(calVal_eepromAdress, newCalibrationValue);

Serial.print("Value ");

Serial.print(newCalibrationValue);

Serial.print(" saved to EEPROM address: ");

Serial.println(calVal_eepromAdress);

_resume = true;

}

else if (inByte == 'n') {

Serial.println("Value not saved to EEPROM");

_resume = true;

}

}

}

Serial.println("End calibration");

Serial.println("***");

Serial.println("To re-calibrate, send 'r' from serial monitor.");

Serial.println("For manual edit of the calibration value, send 'c' from serial monitor.");

Serial.println("***");

}

void changeSavedCalFactor() {

float oldCalibrationValue = LoadCell.getCalFactor();

boolean _resume = false;

Serial.println("***");

Serial.print("Current value is: ");

Serial.println(oldCalibrationValue);

Serial.println("Now, send the new value from serial monitor, i.e. 696.0");

float newCalibrationValue;

while (_resume == false) {

if (Serial.available() > 0) {

newCalibrationValue = Serial.parseFloat();

if (newCalibrationValue != 0) {

Serial.print("New calibration value is: ");

Serial.println(newCalibrationValue);

LoadCell.setCalFactor(newCalibrationValue);

_resume = true;

}

}

}

_resume = false;

Serial.print("Save this value to EEPROM adress ");

Serial.print(calVal_eepromAdress);

Serial.println("? y/n");

while (_resume == false) {

if (Serial.available() > 0) {

char inByte = Serial.read();

if (inByte == 'y') {

#if defined(ESP8266)|| defined(ESP32)

EEPROM.begin(512);

#endif

EEPROM.put(calVal_eepromAdress, newCalibrationValue);

#if defined(ESP8266)|| defined(ESP32)

EEPROM.commit();

#endif

EEPROM.get(calVal_eepromAdress, newCalibrationValue);

Serial.print("Value ");

Serial.print(newCalibrationValue);

Serial.print(" saved to EEPROM address: ");

Serial.println(calVal_eepromAdress);

_resume = true;

}

else if (inByte == 'n') {

Serial.println("Value not saved to EEPROM");

_resume = true;

}

}

}

/*

-------------------------------------------------------------------------------------

HX711_ADC

Arduino library for HX711 24-Bit Analog-to-Digital Converter for Weight Scales

Olav Kallhovd sept2017

-------------------------------------------------------------------------------------

*/

/*

Settling time (number of samples) and data filtering can be adjusted in the config.h file

For calibration and storing the calibration value in eeprom, see example file "Calibration.ino"

The update() function checks for new data and starts the next conversion. In order to acheive maximum effective

sample rate, update() should be called at least as often as the HX711 sample rate; >10Hz@10SPS, >80Hz@80SPS.

If you have other time consuming code running (i.e. a graphical LCD), consider calling update() from an interrupt routine,

see example file "Read_1x_load_cell_interrupt_driven.ino".

This is an example sketch on how to use this library

*/

#include <HX711_ADC.h>

#if defined(ESP8266)|| defined(ESP32) || defined(AVR)

#include <EEPROM.h>

#endif

//pins:

const int HX711_dout = 4; //mcu > HX711 dout pin

const int HX711_sck = 5; //mcu > HX711 sck pin

//HX711 constructor:

HX711_ADC LoadCell(HX711_dout, HX711_sck);

const int calVal_eepromAdress = 0;

unsigned long t = 0;

void setup() {

Serial.begin(57600); delay(10);

Serial.println();

Serial.println("Starting...");

LoadCell.begin();

//LoadCell.setReverseOutput(); //uncomment to turn a negative output value to positive

float calibrationValue; // calibration value (see example file "Calibration.ino")

calibrationValue = 696.0; // uncomment this if you want to set the calibration value in the sketch

#if defined(ESP8266)|| defined(ESP32)

//EEPROM.begin(512); // uncomment this if you use ESP8266/ESP32 and want to fetch the calibration value from eeprom

#endif

//EEPROM.get(calVal_eepromAdress, calibrationValue); // uncomment this if you want to fetch the calibration value from eeprom

unsigned long stabilizingtime = 2000; // preciscion right after power-up can be improved by adding a few seconds of stabilizing time

boolean _tare = true; //set this to false if you don't want tare to be performed in the next step

LoadCell.start(stabilizingtime, _tare);

if (LoadCell.getTareTimeoutFlag()) {

Serial.println("Timeout, check MCU>HX711 wiring and pin designations");

while (1);

}

else {

LoadCell.setCalFactor(calibrationValue); // set calibration value (float)

Serial.println("Startup is complete");

}

}

void loop() {

static boolean newDataReady = 0;

const int serialPrintInterval = 0; //increase value to slow down serial print activity

// check for new data/start next conversion:

if (LoadCell.update()) newDataReady = true;

// get smoothed value from the dataset:

if (newDataReady) {

if (millis() > t + serialPrintInterval) {

float i = LoadCell.getData();

Serial.print("Load_cell output val: ");

Serial.println(i);

newDataReady = 0;

t = millis();

}

}

// receive command from serial terminal, send 't' to initiate tare operation:

if (Serial.available() > 0) {

char inByte = Serial.read();

if (inByte == 't') LoadCell.tareNoDelay();

}

// check if last tare operation is complete:

if (LoadCell.getTareStatus() == true) {

Serial.println("Tare complete");

}

}