Cara Membuat Kompas menggunakan Arduino dan Mengolah IDE

Dalam Proyek Arduino ini, kita akan melihat bagaimana kita dapat membuat kompas yang tampak keren ini menggunakan Arduino, Magnetometer MEMS, dan Processing IDE. Berikut video demonstrasi kompas:

Ringkasan

Yang kita butuhkan untuk proyek ini adalah Magnetometer MEMS, untuk mengukur medan magnet bumi, Papan Arduino dan beberapa kabel jumper. Sebagai contoh, saya akan menggunakan HMC5883L, Magnetometer 3 Sumbu yang terintegrasi dalam papan breakout GY–80.

Cara Kerja Kompas

Bagian Arduino

Pertama kita perlu mendapatkan data dari sensor menggunakan Arduino Board melalui protokol I2C. Kemudian dengan menggunakan nilai X – Axis dan Y – Axis dari sensor kita akan menghitung heading dan mengirimkan nilainya ke Processing IDE melalui Serial Port. Kode berikut akan melakukan tugas tersebut:

/*   Arduino Compass 
 *      
 *  by Dejan Nedelkovski, 
 *  www.HowToMechatronics.com
 *  
 */

#include <Wire.h> //I2C Arduino Library

#define Magnetometer_mX0 0x03  
#define Magnetometer_mX1 0x04  
#define Magnetometer_mZ0 0x05  
#define Magnetometer_mZ1 0x06  
#define Magnetometer_mY0 0x07  
#define Magnetometer_mY1 0x08  


int mX0, mX1, mX_out;
int mY0, mY1, mY_out;
int mZ0, mZ1, mZ_out;

float heading, headingDegrees, headingFiltered, declination;

float Xm,Ym,Zm;


#define Magnetometer 0x1E //I2C 7bit address of HMC5883

void setup(){
  //Initialize Serial and I2C communications
  Serial.begin(115200);
  Wire.begin();
  delay(100);
  
  Wire.beginTransmission(Magnetometer); 
  Wire.write(0x02); // Select mode register
  Wire.write(0x00); // Continuous measurement mode
  Wire.endTransmission();
}

void loop(){
 
  //---- X-Axis
  Wire.beginTransmission(Magnetometer); // transmit to device
  Wire.write(Magnetometer_mX1);
  Wire.endTransmission();
  Wire.requestFrom(Magnetometer,1); 
  if(Wire.available()<=1)   
  {
    mX0 = Wire.read();
  }
  Wire.beginTransmission(Magnetometer); // transmit to device
  Wire.write(Magnetometer_mX0);
  Wire.endTransmission();
  Wire.requestFrom(Magnetometer,1); 
  if(Wire.available()<=1)   
  {
    mX1 = Wire.read();
  }

  //---- Y-Axis
  Wire.beginTransmission(Magnetometer); // transmit to device
  Wire.write(Magnetometer_mY1);
  Wire.endTransmission();
  Wire.requestFrom(Magnetometer,1); 
  if(Wire.available()<=1)   
  {
    mY0 = Wire.read();
  }
  Wire.beginTransmission(Magnetometer); // transmit to device
  Wire.write(Magnetometer_mY0);
  Wire.endTransmission();
  Wire.requestFrom(Magnetometer,1); 
  if(Wire.available()<=1)   
  {
    mY1 = Wire.read();
  }
  
  //---- Z-Axis
  Wire.beginTransmission(Magnetometer); // transmit to device
  Wire.write(Magnetometer_mZ1);
  Wire.endTransmission();
  Wire.requestFrom(Magnetometer,1); 
  if(Wire.available()<=1)   
  {
    mZ0 = Wire.read();
  }
  Wire.beginTransmission(Magnetometer); // transmit to device
  Wire.write(Magnetometer_mZ0);
  Wire.endTransmission();
  Wire.requestFrom(Magnetometer,1); 
  if(Wire.available()<=1)   
  {
    mZ1 = Wire.read();
  }
  
  //---- X-Axis
  mX1=mX1<<8;
  mX_out =mX0+mX1; // Raw data
  // From the datasheet: 0.92 mG/digit
  Xm = mX_out*0.00092; // Gauss unit
  //* Earth magnetic field ranges from 0.25 to 0.65 Gauss, so these are the values that we need to get approximately.

  //---- Y-Axis
  mY1=mY1<<8;
  mY_out =mY0+mY1;
  Ym = mY_out*0.00092;

  //---- Z-Axis
  mZ1=mZ1<<8;
  mZ_out =mZ0+mZ1;
  Zm = mZ_out*0.00092;
  // ==============================
  //Calculating Heading
  heading = atan2(Ym, Xm);
 
  // Correcting the heading with the declination angle depending on your location
  // You can find your declination angle at: https://www.ngdc.noaa.gov/geomag-web/
  // At my location it's 4.2 degrees => 0.073 rad
  declination = 0.073; 
  heading += declination;
  
  // Correcting when signs are reveresed
  if(heading <0) heading += 2*PI;

  // Correcting due to the addition of the declination angle
  if(heading > 2*PI)heading -= 2*PI;

  headingDegrees = heading * 180/PI; // The heading in Degrees unit

  // Smoothing the output angle / Low pass filter 
  headingFiltered = headingFiltered*0.85 + headingDegrees*0.15;

  //Sending the heading value through the Serial Port to Processing IDE
  Serial.println(headingFiltered);

  
  delay(50);
}Code language: Arduino (arduino)

Jika Anda memerlukan detail selengkapnya tentang cara kerja Magnetometer MEMS dan cara mendapatkan data darinya, Anda dapat melihat Tutorial Sensor MEMS saya.

Memproses Bagian IDE

Di sini pertama-tama kita perlu menerima nilai heading yang berasal dari Serial Port. Untuk detail lebih lanjut bagaimana ini dilakukan, Anda dapat memeriksa Arduino dan Tutorial Pemrosesan.

Kompas sebenarnya adalah gambar, atau lebih tepatnya, terdiri dari beberapa gambar transparan yang dimuat ke Processing IDE. Gambar-gambar tersebut berada di direktori kerja sketsa. Setelah menentukan objek gambar di bagian draw() menggunakan fungsi image(), kami memuat gambar latar belakang (yang bersifat opsional, Anda hanya dapat menggunakan warna sederhana untuk latar belakang). Kemudian gambar Kompas dimuat yang menggunakan fungsi rotateZ() yang diputar dengan nilai judulnya. Di atasnya, gambar Compass Arrow dimuat.

Berikut Kode IDE Pemrosesan:

/*   Arduino Compass 
 *      
 *  by Dejan Nedelkovski, 
 *  www.HowToMechatronics.com
 *  
 */
 
import processing.serial.*;
import java.awt.event.KeyEvent;
import java.io.IOException;

Serial myPort;
PImage imgCompass;
PImage imgCompassArrow;
PImage background;

String data="";
float heading;

void setup() {
  size (1920, 1080, P3D);
  smooth();
  imgCompass = loadImage("Compass.png");
  imgCompassArrow = loadImage("CompassArrow.png");
  background = loadImage("Background.png");
  
  myPort = new Serial(this, "COM4", 115200); // starts the serial communication
  myPort.bufferUntil('\n');
}

void draw() {
  
  image(background,0, 0); // Loads the Background image
    
  pushMatrix();
  translate(width/2, height/2, 0); // Translates the coordinate system into the center of the screen, so that the rotation happen right in the center
  rotateZ(radians(-heading)); // Rotates the Compass around Z - Axis 
  image(imgCompass, -960, -540); // Loads the Compass image and as the coordinate system is relocated we need need to set the image at -960x, -540y (half the screen size)
  popMatrix(); // Brings coordinate system is back to the original position 0,0,0
  
  image(imgCompassArrow,0, 0); // Loads the CompassArrow image which is not affected by the rotateZ() function because of the popMatrix() function
  textSize(30);
  text("Heading: " + heading,40,40); // Prints the value of the heading on the screen

  delay(40);
  
}

// starts reading data from the Serial Port
 void serialEvent (Serial myPort) { 
  
   data = myPort.readStringUntil('\n');// reads the data from the Serial Port and puts it into the String variable "data".
  
  heading = float(data); // Convering the the String value into Float value
}
Code language: Arduino (arduino)

Di sini Anda dapat mengunduh file dari proyek, gambar, dan kode sumber: