Ultrasonic Radar using Arduino and Processing
- Robin PJ
- Oct 30
- 2 min read
Posted on October 30, 2025 | By Micromaker Labs Team
Hey radar enthusiasts and code wizards! 👋 Welcome back to the Maker's Build series at Micromaker Labs—where we're turning STEM dreams into spinning reality from our cozy home lab. Kicking off October 1st, we've been all about bite-sized electronics wins for students and hobbyists. Missed the action? Catch Part 1: Auto Night Light for dusk detection magic, or Part 2: Smart Security Alarm that beeps at intruders.
For Part 3, we're going full sci-fi: an Ultrasonic Radar! Mount an HC-SR04 sensor on a sweeping SG90 servo, and watch Arduino ping distances while Processing paints a live 180° radar screen on your screen—complete with glowing sweep line and red blips for nearby objects. It's like a mini submarine sonar for your desk, spotting "enemies" up to 20cm away. Epic for robotics intros or just geeking out on data viz.
What You'll Need 🔧
This one's a software-hardware hybrid—~20 minutes to scan-ready. Stock up via our kits at www.micromakerlabs.com (ESP32 bundles for wireless radar next?):
Arduino UNO (data cruncher—our go-to!)
HC-SR04 Ultrasonic Sensor (distance detective; next Sensor Secrets unpacks its echo tricks)
SG90 Servo Motor (180° sweeper for that radar arc)
Breadboard & Jumper Wires (prototype without the sweat)
Processing 3 (free software for the visual magic—download at processing.org)
Arduino IDE (for code upload)
USB Cable to link worlds
Step-by-Step Wiring Guide 🛠️
Breadboard it simple: Sensor + servo team up on Arduino pins. No soldering, just snaps.
Ultrasonic Sensor (HC-SR04):
VCC to Arduino 5V.
GND to Arduino GND.
TRIG to digital pin 8.
ECHO to digital pin 9.
Servo Motor (SG90):
Signal (orange) to digital pin 11.
VCC (red) to 5V.
GND (brown) to GND.
Launch:
Plug USB, upload Arduino code first.
Fire up Processing—close Serial Monitor to avoid port clashes!
The Code: Brains of the Operation 💻
Two sketches: Arduino sweeps/measures/sends serial data; Processing catches it for radar render. Tweak sweep delay for speed, max_dist for range. Serial baud: 9600.
How to Run:
Arduino: IDE → Upload. Servo sweeps immediately.
Processing: Update port_name (check Serial.list()), hit Run. Green grid + sweep = go!
Place objects 5-20cm—watch red dots trail!
How It Works: The Science Behind the Scan 🔬
From our Into the Basics: Arduino's the scout—servo ticks angles (0-180°), HC-SR04 pings sound waves (343m/s speed calc for cm distances), serial spits "angle,distance." Processing? Visual boss: Maps data to polar coords, draws arcs/lines/points on a 800x450 canvas. Fading history adds that pro radar glow.
Pro move: Bump max_dist for longer range. ESP32 swap? Wireless radar app incoming!
Test & Tweak: Your Turn! 🧪
Clear Space: Sweep line solo-dances, distances max out.
Object Drop: Hand/book in arc—red dot + fade trail. Tune SWEEP_DELAY for smoothness.
Challenge: Add color-coded ranges or Bluetooth (Pixibot-style). Share scans @micromakerlabs!
Micromaker Labs magic: Code + circuits = wow. Shot on i5 13th Gen with S22 Ultra overheads and LED lights—weekly reels locked.
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