https://github.com/aldaviva/webscale
⚖ Measure weight using a Stamps.com digital USB postage scale.
https://github.com/aldaviva/webscale
postage scale stamps-com usb-hid weight
Last synced: about 1 year ago
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⚖ Measure weight using a Stamps.com digital USB postage scale.
- Host: GitHub
- URL: https://github.com/aldaviva/webscale
- Owner: Aldaviva
- License: mit
- Created: 2014-09-26T08:12:29.000Z (over 11 years ago)
- Default Branch: master
- Last Pushed: 2025-03-29T05:00:19.000Z (about 1 year ago)
- Last Synced: 2025-05-07T18:01:54.081Z (about 1 year ago)
- Topics: postage, scale, stamps-com, usb-hid, weight
- Language: JavaScript
- Homepage: https://www.npmjs.com/package/webscale
- Size: 22.5 KB
- Stars: 9
- Watchers: 3
- Forks: 4
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
WebScale
========
Measure weight using a Stamps.com digital USB postage scale.
## Hardware
*I successfully performed these steps in [September 2014](https://twitter.com/Aldaviva/status/516771809962651648). Today, it may work differently, or not at all.*
1. Sign up for free trial at [Stamps.com](https://registration.stamps.com/registration/).
2. During signup, request a complimentary [5-pound digital postage scale](https://store.stamps.com/collections/hardware/products/5lb-scale). Pay $9.99 USD shipping and handling.
3. Before the four-week trial is up, [cancel your account](https://www.stamps.com/postage-online/faqs/) and avoid the monthly fee.
## Installation
[This package is available on npm.](https://www.npmjs.com/package/webscale)
```sh
$ npm install webscale
```
In the event of installation trouble, refer to the [node-hid documentation](https://github.com/node-hid/node-hid/blob/master/README.md).
## Usage
```javascript
const WebScale = require('webscale');
const webScale = new WebScale();
webScale.on('change:weight', ounces => {
console.log(`${ounces} oz.`);
});
```
See also [`test-client.js`](https://github.com/Aldaviva/webscale/blob/master/test-client.js).
## Events
### change:weight
Called whenever the scale's weight reading changes.
#### Arguments
- **ounces** how much weight is on the scale, in ounces. Floating-point number with precision of one digit after the decimal place (tenths of ounces). Can be negative if the scale was tared with weight on it.
### connected
Called when the program first starts and connects successfully to the device, or when it reconnects after losing the connection.
### disconnected
Called when the device is unplugged or powered off, and once per reconnect attempt.
### error
An error with the USB device occurred (except disconnections, see above).
#### Arguments
- **error** The error from node-hid.
## Methods
### tare()
Reset the scale so the current weight will be read as zero. The scale will also automatically tare itself each time it powers on.
### disconnect()
Disconnect from the USB device.
## See Also
- **[Aldaviva/WebScale.net](https://github.com/Aldaviva/WebScale.net)** - this library ported from Node.js to .NET