🚨 Ultrasonic Object Detection with Arduino + Servo

This project demonstrates how to build a simple object detection system using an HC-SR04 ultrasonic sensor and an SG90 servo motor. When an object comes within 20 cm, the servo motor reacts accordingly.

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🧠 How It Works

• The HC-SR04 ultrasonic sensor continuously measures the distance to an object.
• If an object is detected within a threshold distance (e.g. < 10 cm), the servo motor rotates to respond.
• Otherwise, the servo remains at its default position.

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🔌 Circuit Diagram

Below is the wiring schematic for this project:

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🔧 Components Used

More details in components.txt

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Noteworthy techniques

Technique	Why it’s interesting
Continuous polling inside loop() → mirrors the browser event loop	Shows how MCU firmware uses the same non-blocking update model web devs rely on.
Linear range conversion with map()	Compresses the 10-bit ADC range (0-1023) to the servo’s 0-180 ° sweep in one line.
Timing distance with pulseIn()	Reads echo pulse width in µs, converts to cm using the speed-of-sound constant.
Single-supply power + common ground plane	Cuts servo jitter and false echoes without extra regulators.

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Non-obvious tech & libs

• Arduino Servo library – drives the SG90 from a single PWM pin.
• TinkerCAD Circuits schematic (ultra_sonic_object_detection.png) – quick virtual test-bed.
• USB CDC Serial Monitor – lightweight telemetry channel for live distance read-outs.

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