What is MinimalUltrasonic?

MinimalUltrasonic is a lightweight, efficient Arduino library designed for ultrasonic distance measurement. It provides a clean, simple API for working with popular ultrasonic sensors like the HC-SR04, Ping))), and Seeed SEN136B5B.

Philosophy

The library is built on three core principles:

1. Minimalism

Keep it simple. No bloat, no unnecessary features. Just accurate distance measurement with the features you actually need.

2. Efficiency

Optimized for minimal memory usage and fast execution. Perfect for memory-constrained Arduino projects.

3. Accuracy

Physics-based calculations using the actual speed of sound, not arbitrary divisors.

Why Choose MinimalUltrasonic?

Compared to Other Libraries

Feature	MinimalUltrasonic	Other Libraries
Memory per sensor	8 bytes	20-40 bytes
Code size	~1.4 KB	3-5 KB
Units supported	6	1-2
Documentation	Comprehensive	Basic
Type safety	Enum-based	Define-based
Precision	Float	Integer

Key Advantages

• Multiple Units - Measure in cm, meters, mm, inches, yards, or miles
• Small Footprint - Minimal memory usage, perfect for resource-constrained projects
• Type Safety - Enum-based API prevents errors at compile time
• Well Documented - Complete API reference, guides, and examples
• Proven - Used in real-world projects, thoroughly tested
• Modern - Built with modern C++ practices

Supported Sensors

HC-SR04 (4-pin)

The most common ultrasonic sensor. Uses separate trigger and echo pins.

Specifications:

• Operating Voltage: 5V DC
• Range: 2cm - 400cm
• Accuracy: ±3mm
• Measuring Angle: ~15°

Ping))) (3-pin)

Parallax ultrasonic sensor with a single signal pin.

Specifications:

• Operating Voltage: 5V DC
• Range: 2cm - 300cm
• Single pin for trigger and echo

Seeed SEN136B5B (3-pin)

Grove-compatible ultrasonic sensor.

Specifications:

• Operating Voltage: 3.3V - 5V DC
• Range: 3cm - 400cm
• Grove connector compatible

Other Compatible Sensors

• HC-SR04+ (3.3V/5V)
• US-015
• JSN-SR04T (waterproof)
• HY-SRF05

How Ultrasonic Sensors Work

Ultrasonic sensors use sound waves to measure distance:

1. Trigger - Send a 10µs HIGH pulse to trigger pin
2. Transmit - Sensor emits 8 ultrasonic pulses at 40kHz
3. Wait - Sound travels to object and bounces back
4. Receive - Echo pin goes HIGH when echo received
5. Calculate - Measure echo pulse duration, calculate distance

The Physics

Speed of Sound = 343 m/s (at 20°C, sea level)
Distance = (Time × Speed of Sound) / 2

The division by 2 is because sound travels to the object and back (round trip).

Use Cases

Robotics

• Obstacle avoidance
• Wall following
• Distance keeping
• Object detection

Home Automation

• Parking assist systems
• Water level monitoring
• Waste bin fill level
• Automatic lighting

Educational

• Physics experiments
• Arduino learning projects
• STEM education
• Sensor integration practice

Industrial

• Tank level monitoring
• Proximity sensing
• Object counting
• Position verification

Version History

v2.0.0 (Current)

• Multiple unit support (6 units)
• Enhanced API with new methods
• Float return type for precision
• Comprehensive documentation
• Improved performance

v1.0.0 (Legacy)

• Basic cm/inch support
• Integer return type
• Simple API

Next Steps

Ready to get started? Check out the Getting Started Guide or jump straight to Installation.

Learn by Doing

The best way to understand the library is to try it! Start with the Basic Usage Example.