#include <HX711_ADC.h>
/*
CG scale for F3F & F3B models
Olav Kallhovd 2016-2017
CG Scale main components:
1 pc load sensor front YZC-133 2kg
1 pc load sensor rear YZC-133 3kg
2 pc HX711 ADC, one for each load sensor (128bit resolution)
1 pc Arduino Pro for the scale
1 pc Arduino Pro for the Serial display
1 pc 16*2 HD44780 LCD for the Serial display
3D printed parts
Max model weight with sensors above: 4 to 4,5kg depending on CG location
*/
#include <HX711_ADC.h> //https://github.com/olkal/HX711_ADC can be installed from the library manager
//Number of samples and some filtering settings can be adjusted in the HX711_ADC.h library file
//The best RATE setting is usually 10SPS, see HX711 data sheet (HX711 pin 15, can usually be set by a solder jumper on the HX711 module)
//RATE 80SPS will also work fine, but conversions will be more noisy, so consider increasing number of samples in HX711_ADC.h
//HX711 constructor (dout pin, sck pint):
HX711_ADC LoadCell_1(A2, A3); //HX711 pins front sensor (DOUT, PD_SCK)
HX711_ADC LoadCell_2(A0, A1); //HX711 pins rear sensor (DOUT, PD_SCK)
// I²C-Display, if available
// Enable I²C-Display?
// #define I2CDISP
#ifdef I2CDISP
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x3F,16,2); // set the LCD address to 0x3F or 0x27 for a 16 chars and 2 line display
#endif
byte ledPin = 3;
byte batRefPin = A4;
char toLCD[20];
byte output;
boolean ledState;
long t1;
long t2;
const int printInterval = 500; // LCD/Serial refresh interval
//*** configuration:
//*** set dimensional calibration values:
const long WingPegDist = 1198; //calibration value in 1/10mm, projected distance between wing support points, measure with calliper
const long LEstopperDist = 300; //calibration value 1/10mm, projected distance from front wing support point to leading edge (stopper pin), measure with calliper
//*** set scale calibration values (best to have the battery connected when doing calibration):
const float ldcell_1_calfactor = 1954.0; // user set calibration factor load cell front (float)
const float ldcell_2_calfactor = 2010.0; // user set calibration factor load cell rear (float)
//***
const long stabilisingtime = 3000; // tare precision can be improved by adding a few seconds of stabilising time
//***
const long CGoffset = ((WingPegDist / 2) + LEstopperDist) * 10;
void setup() {
//***
// 0: Serial-Console (Your PC);
// 1: Serial-LCD (2nd Arduino with SimpleSerialDisplay)
// 2: I2C-LCD (define I2CDISP above!)
output = 0;
//***
Serial.begin(9600);
Serial.write(254);
Serial.write(128);
Serial.print("F3X COG scale ;");
Serial.write(254);
Serial.write(192);
Serial.print("Bat:");
int batval = readBattVoltage();
Serial.write((char)(batval / 1000) + 48);
Serial.print(".");
Serial.write((char)((batval % 1000) / 100) + 48);
Serial.write((char)((batval % 100) / 10) + 48);
Serial.print("V ");
if (output == 0) { //if output to serial terminal
Serial.println();
Serial.println("Wait for stabilising and tare...");
}
#ifdef I2CDISP
if (output != 0)
Serial.println("You have I2CDISP defined, but output is not 2. Are you sure thats right?");
Serial.println("Initializing I2C-Display");
lcd.init();
lcd.backlight();
lcd.setCursor(0, 0);
lcd.print("F3X COG scale,");
lcd.setCursor(0, 1);
lcd.print("at your service!");
#endif
LoadCell_1.begin();
LoadCell_2.begin();
byte loadcell_1_rdy = 0;
byte loadcell_2_rdy = 0;
while ((loadcell_1_rdy + loadcell_2_rdy) < 2) { //run startup, stabilisation and tare, both modules simultaneously
if (!loadcell_1_rdy) loadcell_1_rdy = LoadCell_1.startMultiple(stabilisingtime);
if (!loadcell_2_rdy) loadcell_2_rdy = LoadCell_2.startMultiple(stabilisingtime);
}
LoadCell_1.setCalFactor(ldcell_1_calfactor); // set calibration factor
LoadCell_2.setCalFactor(ldcell_2_calfactor); // set calibration factor
pinMode(ledPin, OUTPUT); //led
digitalWrite(ledPin, HIGH);
if (output == 1) { //if output to LCD
Serial.write(254);
Serial.write(127); // clear lcd
}
}
int readBattVoltage() { // read battery voltage
long battvalue = 0;
battvalue += analogRead(batRefPin);
battvalue += analogRead(batRefPin);
battvalue *= 4883L; // analog reading * (5.00V*1000000)/1024 (adjust value if VCC is not 5.0V)
battvalue /= 640L; // this number comes from the resistor divider value ((R2/(R1+R2))*1000)/noof analogreadings (adjust value if required)
//Serial.println(battvalue);
if (battvalue < 7500) { //
//low bat warning code goes here, not implemented
}
return battvalue;
}
void flashLED() {
if (t2 < millis()) {
if (ledState) {
t2 = millis() + 2000;
ledState = 0;
}
else {
t2 = millis() + 100;
ledState = 1;
}
digitalWrite(ledPin, ledState);
}
}
void loop() {
//library function update() should be called at least as often as HX711 sample rate; >10Hz@10SPS, >80Hz@80SPS
//longer delay in scetch will reduce effective sample rate (be careful with delay() in loop)
LoadCell_1.update();
LoadCell_2.update();
// calculate CG and update serial/LCD
if (t1 < millis()) {
t1 = millis() + printInterval;
float a = LoadCell_1.getData();
float b = LoadCell_2.getData();
long weightAvr[3];
float CGratio;
long CG;
weightAvr[0] = a * 100;
weightAvr[1] = b * 100;
long weightTot = weightAvr[0] + weightAvr[1];
if (weightAvr[0] > 500 && weightAvr[1] > 500) {
long a = weightAvr[1] / 10;
long b = weightAvr[0] / 10;
CGratio = (((a * 10000) / (a + b)));
CG = ((((WingPegDist) * CGratio) / 1000) - ((WingPegDist * 10) / 2) + CGoffset);
}
else {
CG = 0;
}
// if output = 0: print result to serial terminal:
if (output == 0) {
for (byte a = 0; a < 2; a++) {
Serial.print("weight_LdCell_");
Serial.print(a + 1);
Serial.print(": ");
long i = weightAvr[a];
if (i < 0) {
Serial.print('-');
i = ~weightAvr[a];
}
Serial.print(i / 100);
Serial.print('.');
if ((i % 100) < 10) {
Serial.print("0");
}
Serial.print(i % 100);
Serial.print(" ");
}
Serial.print("CG:");
Serial.print(CG / 100);
Serial.print('.');
Serial.println(CG % 100);
} else if (output == 1) { //if output = 1: print to serial LCD
toLCD[0] = 254;
toLCD[1] = 192;
toLCD[2] = 'W';
toLCD[3] = 't';
toLCD[4] = ':';
if (weightTot < 0 && weightTot >= - 100) {
weightTot = 0;
}
if (weightTot < -100) {
toLCD[5] = 'E';
toLCD[6] = 'r';
toLCD[7] = 'r';
toLCD[8] = '.';
}
else {
toLCD[5] = (char)(weightTot / 100000) + 48;
toLCD[6] = (char)((weightTot % 100000) / 10000) + 48;
toLCD[7] = (char)((weightTot % 10000) / 1000) + 48;
toLCD[8] = (char)((weightTot % 1000) / 100) + 48;
}
toLCD[9] = ' ';
if (CG != 0) {
toLCD[10] = 'C';
toLCD[11] = 'G';
toLCD[12] = ':';
toLCD[13] = (char)(CG / 10000) + 48;
toLCD[14] = (char)((CG % 10000) / 1000) + 48;
toLCD[15] = (char)((CG % 1000) / 100) + 48;
toLCD[16] = '.';
toLCD[17] = (char)((CG % 100) / 10) + 48;
}
else {
for (byte s = 10; s < 18; s++) {
toLCD[s] = ' ';
}
}
toLCD[18] = ';';
for (byte i = 0; i < sizeof(toLCD) - 1; i++) {
Serial.write(toLCD[i]);
}
} else if (output == 2) { //if output = 2: print to I2C LCD
#ifdef I2CDISP
lcd.clear();
// 1st Line: Weight
lcd.setCursor(0, 0);
if (weightTot < 0 && weightTot >= - 100)
weightTot = 0;
if (weightTot < -100)
lcd.print("Wt: Error!");
else {
sprintf(toLCD, "Wt: %ug", weightTot/100);
lcd.print(toLCD);
}
// 2nd Line: CG
lcd.setCursor(0, 1);
if (CG == 0)
lcd.print("CG: Error!");
else {
sprintf(toLCD, "CG: %ld.%ldmm", CG/100, CG%100);
lcd.print(toLCD);
}
#endif
}
readBattVoltage();
}
flashLED();
}
![20210219_205039_001[1].jpg](https://www.rc-network.de/data/attachments/2201/2201469-72c0e1fdb5b42107829b1919cb25195d.jpg "20210219_205039_001[1].jpg")
)
