Arduino 教程：使用 Arduino 与 HC-SR04 制作雷达系统

本文介绍了如何用超声波传感器、伺服电机和 Arduino 以及 Processing IDE，开发了可视化雷达系统。

我用超声波传感器和伺服电机、Processing IDE开发了雷达的视觉体验。我选择了我的项目的大脑是 Arduino Uno。

材料清单

• HC-SR04 超声波传感器
• SG90 9g 微型数字化伺服电机
• Arduino UNO 和 Genuino UNO
• 杜邦线

电路图

Arduino 部分

• 首先，我制作了一个纸板架，用于将超声波传感器连接到伺服电机。如上所示，我只是把它拧在伺服电机上，按照原理图中所示进行连接
• 将代码上传到 Arduino

#include<Servo.h>
int trigPin=2;
int echoPin=3;

long duration;
int distance;
Servo servo;

void setup()
{
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  Serial.begin(9600);
  servo.attach(9);
}

void loop()
{
  for(int i=15;i<=165;i++)
  {
    servo.write(i);
    delay(100);
    distance=calculateDistance();

    Serial.print(i);
    Serial.print(",");
    Serial.print(distance);
    Serial.print(".");
  }
  for(int i=165;i>15;i--)
  {
    servo.write(i);
    delay(100);
    distance=calculateDistance();

    Serial.print(i);
    Serial.print(",");
    Serial.print(distance);
    Serial.print(".");
  }
}

int calculateDistance()
{
  digitalWrite(trigPin,LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin,HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin,LOW);

  duration=pulseIn(echoPin,HIGH);
  distance=duration*0.034/2;
  return distance;
}

• 检查串行监视器是否超声波传感器工作（第一个显示伺服旋转角度，下一个显示超声波传感器测量的距离）。
• 关闭 Arduino IDE

Processing IDE 部分

Processing 开发环境（PDE）使编写处理程序变得容易。程序在文本编辑器中写入，然后按下运行按钮启动。在 Processing 中，一个计算机程序被称为草图（sketch）。草图（sketch）存储在Sketchbook中，它是计算机上的一个文件夹。

草图（sketch）可以绘制二维和三维图形。默认渲染器用于绘制二维图形。 P3D 渲染器可以绘制三维图形，包括控制摄像机，灯光和材料。P2D 渲染器是用于快速绘制二维图形，但不太准确的渲染器。如果您的计算机具有兼容 OpenGL 的图形卡，则 P2D 和 P3D 渲染器都会加速。

Processing 功能通过库和工具进行扩展。库使草图（sketch）能够完成核心处理代码以外的任务。 Processing社区提供了数百个库，可以添加到您的草图（sketch）中，以播放声音，进行计算机视觉以及使用高级 3D 几何体等新功能。工具扩展了PDE，通过为选择颜色等任务提供接口，使绘制草图（sketch）变得更容易。

Processing 有不同的编程模式，以便能够在不同的平台上部署草图并以不同的方式进行编程。 Java模式是默认的。其他编程模式可以通过从PDE右上角的菜单中选择“添加模式...”来下载。

• 下载 Processing IDE：https://processing.org/download/
• 解压 zip 文件并通过单击 processing.exe 文件来安装软件
• 将下面的代码粘贴到 Processing IDE 中

*
*   Updated version. Fits any screen resolution!
*   Just change the values in the size() function,
*   with your screen resolution.
*
*  by Dragon nekhil
*  www.HowToMechatronics.com
*
* /
import processing.serial.*; // imports library for serial communication
import java.awt.event.KeyEvent; // imports library for reading the data from the serial port
import java.io.IOException;
Serial myPort; // defines Object Serial
// defubes variables
String angle = "";
String distance = "";
String data = "";
String noObject;
float pixsDistance;
int iAngle, iDistance;
int index1 = 0;
int index2 = 0;
PFont orcFont;
void setup() {
  size (1366, 768); // ***CHANGE THIS TO YOUR SCREEN RESOLUTION***
  smooth();
  myPort = new Serial(this, "COM7", 9600); // starts the serial communication
  myPort.bufferUntil('.'); // reads the data from the serial port up to the character '.'. So actually it reads this: angle,distance.
  orcFont = loadFont("OCRAExtended-30.vlw");
}
void draw() {
  fill(98, 245, 31);
  textFont(orcFont);
  // simulating motion blur and slow fade of the moving line
  noStroke();
  fill(0, 4);
  rect(0, 0, width, height - height * 0.065);
  fill(98, 245, 31); // green color
  // calls the functions for drawing the radar
  drawRadar();
  drawLine();
  drawObject();
  drawText();
}
void serialEvent (Serial myPort) { // starts reading data from the Serial Port
  // reads the data from the Serial Port up to the character '.' and puts it into the String variable "data".
  data = myPort.readStringUntil('.');
  data = data.substring(0, data.length() - 1);
  index1 = data.indexOf(","); // find the character ',' and puts it into the variable "index1"
  angle = data.substring(0, index1); // read the data from position "0" to position of the variable index1 or thats the value of the angle the Arduino Board sent into the Serial Port
  distance = data.substring(index1 + 1, data.length()); // read the data from position "index1" to the end of the data pr thats the value of the distance
  // converts the String variables into Integer
  iAngle = int(angle);
  iDistance = int(distance);
}
void drawRadar() {
  pushMatrix();
  translate(width / 2, height - height * 0.074); // moves the starting coordinats to new location
  noFill();
  strokeWeight(2);
  stroke(98, 245, 31);
  // draws the arc lines
  arc(0, 0, (width - width * 0.0625), (width - width * 0.0625), PI, TWO_PI);
  arc(0, 0, (width - width * 0.27), (width - width * 0.27), PI, TWO_PI);
  arc(0, 0, (width - width * 0.479), (width - width * 0.479), PI, TWO_PI);
  arc(0, 0, (width - width * 0.687), (width - width * 0.687), PI, TWO_PI);
  // draws the angle lines
  line(-width / 2, 0, width / 2, 0);
  line(0, 0, (-width / 2)*cos(radians(30)), (-width / 2)*sin(radians(30)));
  line(0, 0, (-width / 2)*cos(radians(60)), (-width / 2)*sin(radians(60)));
  line(0, 0, (-width / 2)*cos(radians(90)), (-width / 2)*sin(radians(90)));
  line(0, 0, (-width / 2)*cos(radians(120)), (-width / 2)*sin(radians(120)));
  line(0, 0, (-width / 2)*cos(radians(150)), (-width / 2)*sin(radians(150)));
  line((-width / 2)*cos(radians(30)), 0, width / 2, 0);
  popMatrix();
}
void drawObject() {
  pushMatrix();
  translate(width / 2, height - height * 0.074); // moves the starting coordinats to new location
  strokeWeight(9);
  stroke(255, 10, 10); // red color
  pixsDistance = iDistance * ((height - height * 0.1666) * 0.025); // covers the distance from the sensor from cm to pixels
  // limiting the range to 40 cms
  if (iDistance < 40) {
    // draws the object according to the angle and the distance
    line(pixsDistance * cos(radians(iAngle)), -pixsDistance * sin(radians(iAngle)), (width - width * 0.505)*cos(radians(iAngle)), -(width - width * 0.505)*sin(radians(iAngle)));
  }
  popMatrix();
}
void drawLine() {
  pushMatrix();
  strokeWeight(9);
  stroke(30, 250, 60);
  translate(width / 2, height - height * 0.074); // moves the starting coordinats to new location
  line(0, 0, (height - height * 0.12)*cos(radians(iAngle)), -(height - height * 0.12)*sin(radians(iAngle))); // draws the line according to the angle
  popMatrix();
}
void drawText() { // draws the texts on the screen
  pushMatrix();
  if (iDistance > 40) {
    noObject = "Out of Range";
  }
  else {
    noObject = "In Range";
  }
  fill(0, 0, 0);
  noStroke();
  rect(0, height - height * 0.0648, width, height);
  fill(98, 245, 31);
  textSize(25);
  text("10cm", width - width * 0.3854, height - height * 0.0833);
  text("20cm", width - width * 0.281, height - height * 0.0833);
  text("30cm", width - width * 0.177, height - height * 0.0833);
  text("40cm", width - width * 0.0729, height - height * 0.0833);
  textSize(40);
  text("Object: " + noObject, width - width * 0.875, height - height * 0.0277);
  text("Angle: " + iAngle + " °", width - width * 0.48, height - height * 0.0277);
  text("Distance: ", width - width * 0.26, height - height * 0.0277);
  if (iDistance < 40) {
    text("        " + iDistance + " cm", width - width * 0.225, height - height * 0.0277);
  }
  textSize(25);
  fill(98, 245, 60);
  translate((width - width * 0.4994) + width / 2 * cos(radians(30)), (height - height * 0.0907) - width / 2 * sin(radians(30)));
  rotate(-radians(-60));
  text("30°", 0, 0);
  resetMatrix();
  translate((width - width * 0.503) + width / 2 * cos(radians(60)), (height - height * 0.0888) - width / 2 * sin(radians(60)));
  rotate(-radians(-30));
  text("60°", 0, 0);
  resetMatrix();
  translate((width - width * 0.507) + width / 2 * cos(radians(90)), (height - height * 0.0833) - width / 2 * sin(radians(90)));
  rotate(radians(0));
  text("90°", 0, 0);
  resetMatrix();
  translate(width - width * 0.513 + width / 2 * cos(radians(120)), (height - height * 0.07129) - width / 2 * sin(radians(120)));
  rotate(radians(-30));
  text("120°", 0, 0);
  resetMatrix();
  translate((width - width * 0.5104) + width / 2 * cos(radians(150)), (height - height * 0.0574) - width / 2 * sin(radians(150)));
  rotate(radians(-60));
  text("150°", 0, 0);
  popMatrix();
}

• 在 Processing IDE中选择 tools -> create 字体，并将文件名设置为 OCRAExtended-48，大小为 30，然后单击确定。
• 在上面的 Processing 代码中设置 Arduino 连接的端口

myPort = new Serial(this,"COM7", 9600); // starts the serial communication 

• 运行代码
• 如果它不适合这样的屏幕，根据您的计算机的屏幕分辨率更改下面的程序段。

size (1366, 768); // ***CHANGE THIS TO YOUR SCREEN RESOLUTION*** 

• 工作结束了。 我们来检查一下

测试

• 工作如下所示
• 如果在超声波传感器前面放置障碍物，将会如此显示：

• 自己动手吧。

原文链接：https://create.arduino.cc/projecthub/nekhil-ravi/arduino-based-radar-system-e865e6