CaveCar

Team: Serial Byters

Version: 1.0.1

Authors: Surya K, Varghese K James, Sujith M

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Overview

CaveCar is a small Arduino-based robotic platform designed to explore and map low-ceiling environments (for example, caves or tunnels). The vehicle uses a pair of DC motors for locomotion, an ultrasonic sensor to measure ceiling distance, an IR sensor for obstacle detection, and a servo-mounted ultrasonic sensor to sweep and profile the cave ceiling.

This repository contains the primary control sketch for the CaveCar platform.

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Features

• Forward/backward and turning control for a differential-drive vehicle.
• IR-based immediate obstacle detection and avoidance (turns right when obstacle detected).
• Ultrasonic distance measurement to map the cave ceiling.
• Servo sweep (steps of 18°) to build a simple ASCII-based cave ceiling profile printed over Serial.

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Hardware

Required Components

• Arduino (Uno, Nano or compatible)
• 2 × DC motors with an H-bridge motor driver (e.g. L298N or similar)
• 1 × HC-SR04 ultrasonic distance sensor
• 1 × IR proximity sensor (digital output)
• 1 × Servo motor (for sweeping the ultrasonic sensor)
• Power supply/battery pack appropriate for motors and Arduino
• Wires, chassis, wheels, and other mechanical parts

Pinout (as used in the sketch)

• Servo: D3
• IR sensor (digital input): D2
• Ultrasonic trig: D6
• Ultrasonic echo: D5
• Left motor forward: D8
• Left motor backward: D9
• Right motor forward: D11
• Right motor backward: D10

Adjust pins in the sketch if you use different wiring or a different motor driver board.

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Wiring Notes

• Connect the servo signal to D3, and power the servo from a stable 5V source (use separate motor power if needed). Common ground between motor supply and Arduino is required.
• Wire the HC-SR04 trig to D6 and echo to D5. If your board runs at 5V the HC-SR04 works directly; for 3.3V logic boards use an appropriate level shifter on the echo pin.
• IR sensor digital output to D2.
• Motor driver inputs to D8, D9, D10, D11. Follow your motor driver wiring guide for enable pins and motor power.

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Software / Dependencies

• Arduino IDE (or PlatformIO)
• Servo.h (built-in Arduino library)

No external libraries beyond the Arduino core and Servo are required.

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Uploading

1. Open the sketch in Arduino IDE.
2. Select your board and correct COM/serial port.
3. Click Upload.
4. Open the Serial Monitor at 9600 baud to view debug output and the ASCII ceiling map.

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How It Works (high level)

1. The main loop() reads the IR sensor to check for nearby obstacles.
2. Before moving, the car calls stopCar() then mapCaveCeiling() to perform a servo sweep and sample ceiling distances.
3. If the IR sensor reads LOW (0) the car considers that an obstacle and executes turnRight() for a short period, then stops.
4. If the path is clear the car moves forward for a fixed duration.

Important functions

• moveForward() — sets motor pins to drive both wheels forward.
• turnRight() — runs left motor forward and right motor backward to pivot right.
• stopCar() — brakes/halts both motors.
• getDistance() — triggers the HC-SR04 and returns measured distance in centimeters.
• mapCaveCeiling() — uses getDistance() and the servo sweep function t18() to produce a 10-step ASCII map of the ceiling. Each symbol encodes a height band.
• t18() — steps the servo by 18 degrees per call, updating a pos variable.

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Serial Output / Mapping Legend

When mapCaveCeiling() runs it prints one line of output characters representing 10 distance samples:

• # — distance < 10 cm (very low ceiling)
• * — distance < 20 cm (low ceiling)
• - — distance < 30 cm (medium ceiling)
• . — distance < 40 cm (high ceiling)
• (space) — distance >= 40 cm (very high ceiling)

Additionally, each measurement prints the numeric distance (in cm) to Serial.

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Contact / Authors

• Surya K
• Varghese K James
• Sujith M

For questions or contributions, open an issue or send a pull request.

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Changelog

• 1.0.1 — Initial documented release and minor cleanup.