nodeusbscale

Node.js+Linux (HID) bindings for several USB scales (Pitney Bowes, Dymo, etc.)

Tested with:

• 0922:8004 Dymo-CoStar Corp.
• 0d8f:0200 Pitney Bowes

Data packets are in the following format:

{
	'weight': xxxxxx,
	'balanced': <true/false>
}

Example

#!/usr/bin/env node

var UsbScale = require('nodeusbscale');

var dev = UsbScale.create();
dev.open( '/dev/usb/hiddev0', function(obj, err) {
	if( err ) {
		console.log("UsbScale: Failed to open device: "+err);
		return false;
	}
	dev['data'] = function(data) {
		console.log("UsbScale event: "+JSON.stringify(data, null, 2));
	};
});

// Hack to prevent Node.js from exiting, sorry.
var http = require('http');
var httpServer = http.createServer(function(){});
httpServer.listen(8084);
console.log("Listening for keyboard input...");

Methods

Factory

usbscale::create()

Returns an initialised usbscale object.

• Returns: An initialised usbscale object.

usbscale object

usbscaleObject::open( path, callback( usbscaleObject, error ) )

Open an usbscale device, associate it to this object, and fire the provided callback upon completion.

The parameters passed to the provided callback function are usbscaleObject which is a reference to the usbscale object, and error which will be an error string in the case of an error, or undefined on success.

• Returns: A reference to itself.

usbscaleObject::data( usbscaleEvent )

A virtual method of the usbscaleObject. Reimplement it to handle usbscaleEvents. It can be ignored, but if you ignore it, you might as well not use this module at all.