Objective
To build a radar system that scans the area and displays the angle and distance of objects on a computer screen.
What will you Learn:
1. Ultrasonic distance measurement
2. Servo motor control
3. Serial communication between Arduino and PC
4. Data visualization with Processing
5. How radar and sonar work
6. Arduino programming
How it works
The HC-SR04 sends an ultrasonic pulse from TRIG and measures how long the echo takes to return on ECHO.
Distance (cm) = time x 0.034 / 2
The servo rotates one degree at a time and Arduino sends the data as angle,distance. over the serial port. Processing reads the data, draws the sweeping line and shows a red mark when an object is closer than 40 cm.
Components you'll need
| Component | Qty | Availability | Price | |
|---|---|---|---|---|
| Jumper Wire Set (120 pcs) | ×1 | In stock | $2.99 | |
 SG90 Micro Servo | ×1 | In stock | $1.39 | |
 Arduino UNO R3 (compatible) | ×1 | In stock | $5.19 | |
 HC-SR04 Ultrasonic Sensor | ×1 | In stock | $1.19 | |
 Breadboard medium | ×1 | In stock | $0.99 | |
| Bought one by one | $11.75 | |||
All of these come in ThinkNMake Maker Kit.
Circuit & connections
The full wiring diagram and pin-by-pin connections.
Code
The complete, tested sketch (120 lines), ready to upload.
Step-by-step instructions
Troubleshooting
Fixes for the problems makers hit most often on this build.
