In this tutorial, we are going to make a RADAR system using Arduino nano, an ultrasonic sensor, and a servo motor. The word RADAR stands for “Radio Detection and Ranging”. This RADAR system can detect both stationary and moving objects within its range.
In this project, we are going to use an ultrasonic sensor to detect objects at a certain distance and angles.
Ultrasonic sensor
You can see in the above picture that the ultrasonic sensor consists of two major parts. The first part is a transmitter and the other part is a receiver. This sensor has 4 pins
Pin | Description |
|
|
Vcc | +5v DC supply |
Trig | Data output |
Echo | Command input |
Gnd | 0v DC |
The ultrasonic sensor is used to detect objects at a certain distance. It can also measure the distance between the object and the sensor by the concept of sound navigation and ranging (SONAR). The operating frequency of the ultrasonic sensor is 40KHz.
Servo motor
The above picture shows a servo motor. A servo motor is a simple DC motor with some gears. It provides more control when compared to a simple dc motor. We can control the rotation of the motor with respect to speed and direction. The servo motor is based on the concept of a closed-loop mechanism, which means it uses feedback to control every action of the motor.
Generally, DC motors work according to the given power supply, but servo motors work according to signals given to them.
Servo motors are generally used in engineering projects and toys like airplanes, cars, etc.
Working of RADAR
The ultrasonic sensor consists of two parts. The transmitter and the receiver. The transmitter part transmits the ultrasonic waves. These waves when hitting any object returns back and get received by the receiver. In this way, the object gets detected.
Now we need to find the distance of the object from the sensor. To calculate distance we need two different data that is the speed of sound wave (332 meters per second) and the time taken by the wave to return to the receiver.
The formula for calculating distance is
D = ½ T x S
Where,
D = distance between object and sensor
T = time taken by the sound wave to return to the receiver.
S = speed of sound
Connection
Arduino pins | Connection |
Pin D2 | Trigger pin of ultrasonic sensor. |
Pin D3 | Echo pin of ultrasonic sensor. |
Pin D9 | Servo signal pin. |
5v | Positive supply of ultrasonic sensor and servo motor. |
Gnd | Ground supply of ultrasonic sensor and servo motor. |
We are not going to use any power supply for this circuit. The circuit can power itself from the connected computer through cable. If you want to operate it without cable, then provide Arduino nano with 5v dc supply.
Arduino code
#include <Servo.h> //include library of servo
Servo myServo; //create an object of your name
int dis;
void setup() {
pinMode(2, OUTPUT); //define Arduino pin for trig
pinMode(3, INPUT); //define Arduino pin for echo
Serial.begin(9600); //it tells Arduino to get ready to send and receive messages with a bit rate of 9600 bits per second.
myServo.attach(9); //connect servo data pin to pin 9 of arduino
}
void loop()
{
for (int x = 0; x <= 180; x++) // define angle to turn left
{ //servo turn left
myServo.write(x); //rotate servo as defined in x
dis=distance();
Serial.print(x); //print servo angle
Serial.print(“,”);
Serial.print(dis); //print ultrasonic distance readings
Serial.print(“.”);
delay(50); // delay 50 micro second before turning right
}
for (int y = 179; y > 0; y–) // define angle to turn right
{//servo turn right
myServo.write(y); //rotate servo
dis=distance();
Serial.print(y); //print servo angle
Serial.print(“,”);
Serial.print(dis); //print ultrasonic distance readings
Serial.print(“.”);
delay(50); // delay 50 microsecond before turning left
}
}
//ultrasonic sensor code
int distance()
{
digitalWrite(2, LOW); // put pin 2 (trig) low
delayMicroseconds(4); // delay 4 microsecond
digitalWrite(2, HIGH); // put pin 2 (trig) high
delayMicroseconds(10); // delay 10 micro second
digitalWrite(2, LOW); // put pin 2 (trig) low
int t = pulseIn(3, HIGH); // data from sensor to arduino
int cm = t*0.032 / 2; //time convert distance
return cm; //return value
}
Processing code
The output screen of the radar is built using processing software. The code for processing software is given below
Serial myport;//create serial object
PFont f;
int Angle, Distance;
String angle=””; // to print angle
String distance=””; // to print distance
String data;
int index1=0;
int index2=0;
float pixsDistance;
void setup() {
size(1600, 700);//screen size
smooth();
printArray(PFont.list()); // show font list your computer
f = createFont(“David Bold”, 28); // define font name and size
textFont(f);
String portName = Serial.list()[0];//set COM port
myport = new Serial(this, portName, 9600);
myport.bufferUntil(‘.’);
}
void draw() {
noStroke();
fill(0, 10);
rect(0, 0, width, 700);
fill(98, 245, 31);
greenmesh();
radararea();
words();
greenLine();
redline();
}
//get ardunio board serial values
void serialEvent (Serial myport) {
data = myport.readStringUntil(‘.’);
data = data.substring(0, data.length()-1);
index1 = data.indexOf(“,”);
angle= data.substring(0, index1);
distance= data.substring(index1+1, data.length());
// converts the String variables into Integer
Angle = int(angle);
Distance = int(distance);
}
//Half circle and lines
void radararea() {
pushMatrix();
translate(625, 680);
noFill();
strokeWeight(2);
stroke(98, 245, 31);
// draws the arc lines
arc(0, 0, 1150, 1150, PI, TWO_PI);
arc(0, 0, 850, 850, PI, TWO_PI);
arc(0, 0, 550, 550, PI, TWO_PI);
arc(0, 0, 250, 250, PI, TWO_PI);
// draws the angle lines
line(-450, 0, 450, 0);
line(0, 0, -600*cos(radians(30)), -600*sin(radians(30)));
line(0, 0, -600*cos(radians(60)), -600*sin(radians(60)));
line(0, 0, -600*cos(radians(90)), -600*sin(radians(90)));
line(0, 0, -600*cos(radians(120)), -600*sin(radians(120)));
line(0, 0, -600*cos(radians(150)), -600*sin(radians(150)));
line(-960*cos(radians(30)), 0, 960, 0);
popMatrix();
}
//Green box net
void greenmesh() {
stroke(98, 245, 31);
strokeWeight(0.1);
for (int x=0; x<=700; x+=5) {
line(0, x, width, x);
}
for (int y=0; y<=1250; y+=5) {
line(y, 0, y, height);
}
}
//print text
void words() {
fill(98, 245, 31);
text(“180′”, 10, 670);
fill(98, 245, 31);
text(“0′”, 1210, 670);
fill(98, 245, 31);
text(“30′”, 1160, 380);
fill(98, 245, 31);
text(“60′”, 940, 160);
fill(98, 245, 31);
text(“90′”, 615, 70);
fill(98, 245, 31);
text(“120′”, 310, 150);
fill(98, 245, 31);
text(“150′”, 80, 370);
fill(255);
text(“SriTu Tech Radar system”, 20, 30);
fill(255);
text(“Angle — “+Angle+” ‘”, 20, 60);
fill(255);
text(“Distance — “+Distance+” cm”, 20, 90);
}
//Drawing green lines
void greenLine() {
pushMatrix();
strokeWeight(7);
stroke(30, 250, 60);//green color
translate(625, 680);
line(0, 0, 600*cos(radians(Angle)), -600*sin(radians(Angle)));
popMatrix();
}
//Drawing red lines
void redline() {
pushMatrix();
translate(625, 680);
strokeWeight(7);
stroke(255, 10, 10); //red color
pixsDistance = Distance*22.5;
// limiting the range to 40 cm
if (Distance<40) {
line(pixsDistance*cos(radians(Angle)), -pixsDistance*sin(radians(Angle)), 600*cos(radians(Angle)), -600*sin(radians(Angle)));
}
popMatrix();
}
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