Virtual Displays: The Arduino Radar Mapping

A single HC-SR04 sonar sensor can only measure distance directly in front of it. The Arduino Radar project mimics a submarine or air-traffic control tower. By physically sweeping the sensor across the room and tying the data into a Java application, you construct a complete 2D map of your surroundings.

Servo Kinematics & Data Transmission

The hardware mechanism dictates the software timing.

1. An HC-SR04 Ultrasonic Sensor is hot-glued directly on top of the horn of an SG90 Micro Servo.
2. The Sweep Loop: The Arduino runs a for(pos = 0; pos <= 180; pos++) loop. For every single degree, the servo stops briefly, the sonar fires a ping, and measures the distance (e.g., at degree 45, an object is 10cm away).
3. The Communication Payload: The Arduino compresses these two variables into a comma-separated serial string and blasts it over USB: 45,10.0\n.

Translating Reality to a Digital Display (Processing)

The Serial Monitor strings are useless to a human operator. You must use the Processing IDE on your computer.

• The Java script opens the COM port and swallows the 45,10.0 payload.
• It uses incredibly complex Polar-to-Cartesian trigonometric math (cos(), sin()) to calculate exactly where that object is on the computer screen.
• It draws a sweeping green "Radar Line" that pivots 180 degrees.
• When an object is detected, it draws an intense Red blip precisely where the object is located in the real room! The visual updates flawlessly in real-time as the physical radar sweeps back and forth!

System Elements

• Arduino Uno/Nano: The physical actuator and data aggregator.
• SG90 Servo Motor and HC-SR04 Sensor.
• A heavily weighted 3D-printed chassis (The fast servo motion will make the base chassis flip over if it is not secured down!).
• Processing 3 or 4 IDE running the graphic display code on a PC/Mac.