mmm-usonic v2.5.3

mmm-usonic

A high performance, memory mapped, Node.js API for the HC-SR04 ultrasonic sensor connected to a Raspberry Pi. It's the updated version of clebert's r-pi-usonic API.

Getting Started

Installation

npm install mmm-usonic --save

Integration

var usonic = require('mmm-usonic');

API

usonic.init(callback)

Creates the memory mapping with a device-specific memory offset.

You must call this function only once and before any other function.

usonic.init(function (error) {
    if (error) {
        ...
    } else {
        ...
    }
});

usonic.createSensor(echoPin, triggerPin, timeout)

Creates a new ultrasonic sensor function and returns it. The measurement timeout has a default value of 750 µs.

var sensor = usonic.createSensor(24, 23, 450);

sensor()

Returns the distance in cm if no measurement timeout occurs, and -1 otherwise.

var distance = sensor();

Example

This example needs access to the physical memory, so it must run as root.

sudo node examples/surveyor.js

Raspberry Pi GPIO Pin Layout

Raspberry Pi Model A/B (Rev 1.0)

Raspberry Pi Model A/B (Rev 2.0)

Raspberry Pi Model B+ / Raspberry Pi 2 Model B

Related Links

• Ultrasonic Ranging Module HC-SR04
• Ultraschall Messmodul HC-SR04

Running Tests

To run the test suite first install the development dependencies:

npm install

then run the tests:

npm test