n ultrasonic sonar is a device that measures the distance to an object by emitting sound waves at a frequency higher than the upper limit of human hearing (usually more than 20KHz). It works by sending out sound waves and then measuring the time it takes for the waves to bounce back after hitting an object. By calculating the time difference between sending and receiving the sound wave, and using the speed of sound in the air, the distance to the object can be determined. In some of my previous videos, you can see several different ways of building such devices with special features. They were all built with additional programs written by Processing applications to display the results on a computer monitor.
This time, I will show you a simple way to build a stand-alone sonar device whose results are displayed as a radar image directly on a TFT color display, so it is often mistakenly called a radar instead of a sonar.
Component List
- Arduino Nano R3 × 1
- TFT display with 240 x 320 pixel resolution and ILI9341 driver chip × 1
- HC-SR04 ultrasonic sensor × 1
- Small 9g servo motor × 1
- 2.2KM resistor × 5
- 3.3KM resistor × 5
Tools used
- Soldering iron
- Lead-free solder wire
The servo motor and ultrasonic transducer were mounted in a box I kept from a previous project and connected to the main box via flat cable.
Designed and assembled
The idea came to me when I stumbled across a picture on the web, and then, after some research, I found the project in question on Github. The original project was made on a 1.8-inch display, and for this purpose, that's a very small display space indeed. So I rewrote the code to work on a larger 3.2-inch TFT display so that the image would show up more clearly.
Now, let's delve deeper into the excellent performance of this device in real application scenarios:
First of all, in order to ensure the accuracy of the measurement, I carefully separated the ultrasonic sensor from the servo motor, and meticulously calibrated the correspondence between the graphic display and the actual distance of the object. You'll notice that the distance displayed on the screen matches the actual distance measured to a remarkable degree.
We then mounted the sensor securely on the servo motor and placed an obstacle to be detected. After powering on, the servo motor first performed a smooth test, followed by a radar-like scanning interface on the display and began to scan accurately.
Obstacles are identified on the screen with eye-catching red dots. The lower left corner of the screen clearly shows the current scanning area, while the right side is updated in real time with the distance between the sensor and the obstacle, in units accurate to centimeters. In order to present the distance information more intuitively, we have specially designed three green arcs, which dynamically adjust with the change of distance, enabling users to grasp the actual distance at a glance. When the nearest obstacle is more than 1 meter away, a yellow warning dot will appear on the last arc to remind the user that the scanning range has been exceeded. The scanning process starts from 180 degrees, gradually narrows down to 0 degrees, and then expands from 0 degrees to 180 degrees, realizing all-round coverage.
To ensure stable operation of the device, we recommend using an external power supply, but an option to power the device through the Arduino's USB port is also available for convenience. In addition, users can easily adjust all the display colors in the code to meet different visual needs according to their personal preferences.
Finally, I would like to give a brief summary of this device. Compared to most of its counterparts, it does not rely on a computer monitor to display the scan results, eliminating the need for additional apps and code hassles. It is simple to make, visually appealing and completely self-contained, making it an ideal choice for both beginners and experienced DIY enthusiasts. However, for better user experience, it is recommended to integrate all components into a compact housing with a tilting front display to simulate a real radar system for a more realistic user experience.
Wiring Diagram
Code
Below is the full source code:
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#include <Servo.h> #include <SPI.h>#include "Ucglib.h" #define trigPin 6 #define echoPin 5 #define ServoPin 3 int Ymax = 240;
int Xmax = 320;
int Xcent = Xmax / 2;
int base = 210;
int scanline = 185;
Servo baseServo; //Ucglib_ILI9341_18x240x320_SWSPI ucg(/*sclk=*/ 13, /*data=*/ 11, /*cd=*/ 9, /*cs=*/ 10, /*reset=*/ 8);Ucglib_ILI9341_18x240x320_HWSPI ucg(/*cd=*/ 9, /*cs=*/ 10, /*reset=*/ 8);
void setup(void)
{ ucg.begin(UCG_FONT_MODE_SOLID);
ucg.setRotate90();
pinMode(trigPin, OUTPUT);
pinMode(echoPin, INPUT);
Serial.begin(115200);
baseServo.attach(ServoPin);
ucg.setFontMode(UCG_FONT_MODE_TRANSPARENT);
ucg.setColor(0, 0, 100, 0);
ucg.setColor(1, 0, 100, 0);
ucg.setColor(2, 20, 20,20);
ucg.setColor(3, 20, 20, 20);
ucg.drawGradientBox(0, 0, 320, 240);
ucg.setPrintDir(0);
ucg.setColor(0, 5, 0);
ucg.setPrintPos(70,120);
ucg.setFont(ucg_font_logisoso32_tf);
ucg.print("Mini Radar");
ucg.setColor(0, 255, 0);
ucg.setPrintPos(70,120);
ucg.print("Mini Radar");
ucg.setFont(ucg_font_courB14_tf);
ucg.setColor(20, 255, 20);
ucg.setPrintPos(90,200);
ucg.print("Testing...");
baseServo.write(90);
for(int x=0;x<180;x+=5)
{ baseServo.write(x);
delay(50);
}
ucg.print("OK!");
delay(500);
ucg.setColor(0,0, 0, 0);
ucg.setColor(1,0, 0, 0);
ucg.setColor(2,0, 0, 0);
ucg.setColor(3,0, 0, 0);
ucg.drawGradientBox(0, 0, 320, 240);
delay(10);
//ucg.clearScreen();
cls();
ucg.setFontMode(UCG_FONT_MODE_SOLID);
ucg.setFont(ucg_font_helvR08_hr); // or freedoomr10_tr
}void cls()
{ ucg.setColor(0, 0, 0, 0);
for(int s=0;s<240;s++)
{
ucg.drawHLine(0,s,320);
delay(1);
}
//ucg.drawBox(0, 0, 160, 60);
}int calculateDistance()
{ long duration;
digitalWrite(trigPin, LOW);
delayMicroseconds(2);
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);
duration = pulseIn(echoPin, HIGH);
return duration*0.034/2;
}void fix_font()
{ ucg.setColor(0, 180, 0);
ucg.setPrintPos(144,44);
ucg.print("1.00");
ucg.setPrintPos(144,100);
ucg.print("0.60");
ucg.setPrintPos(144,165);
ucg.print("0.30");
}void fix()
{ ucg.setColor(0, 180, 0);
ucg.drawDisc(Xcent, base+1, 3, UCG_DRAW_ALL);
ucg.drawCircle(Xcent, base+1, 210, UCG_DRAW_UPPER_LEFT);
ucg.drawCircle(Xcent, base+1, 210, UCG_DRAW_UPPER_RIGHT);
ucg.drawCircle(Xcent, base+1, 135, UCG_DRAW_UPPER_LEFT);
ucg.drawCircle(Xcent, base+1, 135, UCG_DRAW_UPPER_RIGHT);
ucg.drawCircle(Xcent, base+1, 70, UCG_DRAW_UPPER_LEFT);
ucg.drawCircle(Xcent, base+1, 70, UCG_DRAW_UPPER_RIGHT);
ucg.drawLine(0, base+1, Xmax,base+1);
ucg.setColor(0, 180, 0);
for(int i= 40;i < 300; i+=2)
{
if (i % 10 == 0)
ucg.drawLine(185*cos(radians(i))+Xcent,base - 185*sin(radians(i)) , 205*cos(radians(i))+Xcent,base - 205*sin(radians(i)));
else
ucg.drawLine(195*cos(radians(i))+Xcent,base - 195*sin(radians(i)) , 205*cos(radians(i))+Xcent,base - 205*sin(radians(i)));
}
ucg.setColor(0,200,0);
ucg.drawLine(0,0,0,36);
for(int i= 0;i < 5; i++)
{
ucg.setColor(0,random(200)+50,0);
ucg.drawBox(2,i*8,random(28)+3,6);
}
ucg.setColor(0,180,0);
ucg.drawFrame(292,0,28,28);
ucg.setColor(0,60,0);
ucg.drawHLine(296,0,20);
ucg.drawVLine(292,4,20);
ucg.drawHLine(296,52,20);
ucg.drawVLine(318,4,20);
ucg.setColor(0,220,0);
ucg.drawBox(296,4,8,8);
ucg.drawBox(296,16,8,8);
ucg.drawBox(308,16,8,8);
ucg.setColor(0,100,0);
ucg.drawBox(308,4,8,8);
ucg.setColor(0,90,0);
ucg.drawTetragon(124,220,116,230,196,230,204,220);
ucg.setColor(0,160,0);
ucg.drawTetragon(134,220,126,230,186,230,194,220);
ucg.setColor(0,210,0);
ucg.drawTetragon(144,220,136,230,176,230,184,220);
}void loop(void)
{ int distance;
fix();
fix_font();
for (int x=180; x > 4; x-=2){
baseServo.write(x);
int f = x - 4;
ucg.setColor(0, 255, 0);
ucg.drawLine(Xcent, base, scanline*cos(radians(f))+Xcent,base - scanline*sin(radians(f)));
f+=2;
ucg.setColor(0, 128, 0);
ucg.drawLine(Xcent, base, scanline*cos(radians(f))+Xcent,base - scanline*sin(radians(f)));
f+=2;
ucg.setColor(0, 0, 0);
ucg.drawLine(Xcent, base, scanline*cos(radians(f))+Xcent,base - scanline*sin(radians(f)));
ucg.setColor(0,200, 0);
distance = calculateDistance();
if (distance < 100)
{
ucg.setColor(255,0,0);
ucg.drawDisc(2.2*distance*cos(radians(x))+ Xcent,-2.2*distance*sin(radians(x))+base, 1, UCG_DRAW_ALL);
}
else
{
ucg.setColor(255,255,0);
ucg.drawDisc(208*cos(radians(x))+Xcent,-208*sin(radians(x))+base, 1, UCG_DRAW_ALL);
}
Serial.print(x);
Serial.print(" , ");
Serial.println(distance);
if (x > 70 and x < 110) fix_font();
ucg.setColor(255,255, 0);
ucg.setPrintPos(20,230);
ucg.print("DEG: ");
ucg.setPrintPos(54,230);
ucg.print(x);
ucg.print(" ");
ucg.setPrintPos(240,230);
ucg.print(" ");
ucg.print(distance);
ucg.print(" cm ");
}
//ucg.clearScreen();
delay(50);
cls();
fix();
fix_font();
for (int x=1; x < 176; x+=2){
baseServo.write(x);
int f = x + 4;
ucg.setColor(0, 255, 0);
ucg.drawLine(Xcent, base, scanline*cos(radians(f))+Xcent,base - scanline*sin(radians(f)));
f-=2;
ucg.setColor(0, 128, 0);
ucg.drawLine(Xcent, base, scanline*cos(radians(f))+Xcent,base - scanline*sin(radians(f)));
f-=2;
ucg.setColor(0, 0, 0);
ucg.drawLine(Xcent, base, scanline*cos(radians(f))+Xcent,base - scanline*sin(radians(f)));
ucg.setColor(0, 200, 0);
distance = calculateDistance();
if (distance < 100)
{
ucg.setColor(255,0,0);
ucg.drawDisc(2.2*distance*cos(radians(x))+Xcent,-2.2*distance*sin(radians(x))+base, 1, UCG_DRAW_ALL);
}
else
{
ucg.setColor(255,255,0);
ucg.drawDisc(208*cos(radians(x))+Xcent,-208*sin(radians(x))+base, 1, UCG_DRAW_ALL);
}
Serial.print(x);
Serial.print(" , ");
Serial.println(distance);
if (x > 70 and x < 110) fix_font();
ucg.setColor(255,255, 0);
ucg.setPrintPos(20,230);
ucg.print("DEG: ");
ucg.setPrintPos(54,230);
ucg.print(x);
ucg.print(" ");
ucg.setPrintPos(240,230);
ucg.print(" ");
ucg.print(distance);
ucg.print(" cm ");
}
//ucg.clearScreen(); //
delay(50);
cls();
} |