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a libraray for nodeJS to talk to a phidget interface kit
JavaScript
Branch: master

Merge pull request #12 from cotejp/master

Added rawValue to sensor events and prevented events from being triggered before "opened".
latest commit 0ed928a539
@cotejp cotejp authored

readme.md

phidgets

A Node.js and iojs.org-compatible JavaScript library to interface with the Phidgets line of hardware boards.

NPM NPM

Phidget boards are a great prototyping tool which can handle digital inputs and outputs, along with a great array of analog sensors (RFID, temperature, distance, etc.). Node.js and io.js are fantastic networking library which makes it easy to create fast networked applications. This project aims to make it simple for them to interact. Synergy!

Warning to users of version <= 0.4.0

The API in version 0.5.0 and above has changed and is not backwards-compatible. We had to make this change in order to support more than just the PhidgetInterfaceKit boards. An archived copy of version 0.4.0 is being kept around for those needing to maintain older projects.

Getting started

This project assumes you have the Phidget WebService up and running. For "regular" (USB) Phidget boards, this simply means that the computer you are connecting to has got the webservice installed and started.

For stand-alone Phidget Single Board Computers (phidgetsbc), this assumes you have configured the server via the web portal. Since you will be connecting to the Phidget server via TCP, be sure you can access the server from the machine running this project.

This library can interface with multiple phidget boards connected to a single computer via the Phidget WebService.

Installation

If you already have Node.js installed, you also have npm installed. This means you can install the phidgets package with:

npm install phidgets`

Phidgets Inc. makes a line of phidget boards which are themselves small ARM Debian computers. It it possble to run Node.js on them, and use this package locally. Here's a gist with the steps and a blog post about how to get this up and running.

Usage

The most common way to interact with a phidgets board is to set up listeners for whatever you are interested in. For example, this code will log to the console all changes detected on the analog sensor inputs of the device:

var phidgets = require('phidgets');

var pik = new phidgets.PhidgetInterfaceKit();

pik.on('sensor', function(emitter, data) {
    console.log('Sensor: ' + data.index + ', value: ' + data.value);
});

pik.open();
Using events

Obviously, many other events are available. The exact events vary with the device type. As an example, here are the events specific to PhidgetInterfaceKit devices:

  • "input" : triggered when a digital input changes status
  • "sensor" : triggered when data is received on the analog sensors
  • "output" : triggered when the status of a digital output changes

The following events are common to all phidgets:

  • "opening" : triggered when a connection to a phidget board is attempted
  • "reopening" : triggered when trying to automatically reconnect to a remotely-closed phidget
  • "timeout" : triggered when a connection attempt times out
  • "opened" : triggered when a the connection attempt has succeeded and the board is ready
  • "closed" : triggered when the connection to the board has been closed (locally or remotely)
  • "error" : triggered when an error occured
Using chaining

Since all relevant functions are chainable, the above example can be written more concisely:

var phidgets = require('phidgets');

var pik = new phidgets.PhidgetInterfaceKit()
    .on('input', function(emitter, data) {
        console.log('Digital input: ' + data.index + ', value: ' + data.value);
    })
    .open();
Calling the open() method

When no parameters are passed to the open() method, the first matching device on the local machine is used. If you have multiple devices connected, you can connect to a specific one by passing its serial number or label (as defined in the Phidget WebService control panel). You can also, if necessary, specify a password:

pik.open({
    serial: 123456,
    label: "mydevice",
    password: "abc"
});

If you need, you can connect to devices on another machine:

pik.open({
    host: "123.123.123.123",
    port: 5001
});
Retrieving data from the board

As illustrated above, you can retrieve data by adding the appropriate listeners ('input', 'sensor', etc.). You can also, at any time, manually check the status of any inputs, sensors, leds, outputs, etc. Depending on the type of board you are using, all of these will or will not be available. For example, on a PhidgetLED board, there are no inputs or sensors. However, you can still read the state of all LEDS by looking at the PhidgetLED.leds object. This object will look like this:

{
    0: 0,
    1: 67,
    2: 0,
    3: 13,
    // etc.
    count: 64 // The total number of inputs/outputs/leds/etc. (as reported by the board)
}

For example, if you wanted to periodically check the status of an analog sensor hooked up to port 3 of a PhidgetInterfaceKit, you could to the following:

var phidgets = require('phidgets');

var pik = new phidgets.PhidgetInterfaceKit()
    .on('opened', function(emitter) {
        setInterval(
            function() {  console.log("Sensor 3: " + pik.sensors[3].value);  },
            1000
        );
    })
    .open();
Sending data to the board

The outputs object is meant to be read-only. If you want to change the value of an output, use the relevant method. For example, to change an output on a PhidgetInterfaceKit, you would use the PhidgetInterfaceKit.setOutput() method. To do the same on a PhidgetLED, you would use PhidgetLED.setBrightness().

Supported boards

Currently, all interface kit boards are supported through the PhidgetInterfaceKit object. This includes boards such as:

  • PhidgetInterfaceKit 8/8/8 normal and mini-format
  • PhidgetInterfaceKit 2/2/2
  • PhidgetInterfaceKit 0/16/16
  • PhidgetInterfaceKit 8/8/8 (with and without hub)

Also included in the library is full support for the following boards:

  • PhidgetLED

Other boards will be added in the future. Help from contributors is always welcomed. Addding support for a specific board is relatively straightforward. If you are in a hurry, and can support the development effort, please contact one of the project contributors.

API Documentation

If this primer wasn't enough, the full API documentation is available for download in the docs folder. You can also view it online.

Things to do:

  • Add support for missing boards.
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