Hi guys,
I'm looking for a program that can read the weight on a USB scale, namely the Pelouze 10lb USB Portable Scale. I thought it would have a virtual COM port driver but instead, it uses HID drivers. I've been searching for a whole month for a program that can help me transfer the reading of the scale to Microsoft Excel. Can someone help me out or point me in the right direction? I am absolutely illiterate to programming. Much gratitude any help given.
I would assume that output from a USB HID device like this should appear to the USB host exactly as if the input was typed on a keyboard, i.e. on the scale stabilising, the weight would be sent over USB. This is the way most USB barcode scanners work.
If this is the case then the scale should just fire across the weight and it would appear in whatever application was active; Excel if that is where you wanted the input to end up.
However, I've looked over the specs and manual for the scale you specify and, unless I'm looking at the wrong model, although it is powered by USB I don't see any mention of the fact that it also communicates over USB. Do you have a URL or part number?
The first question that you will need to answer is the exact HID use. USB describes a wide family of related protocols. USB HID is a subset, but this still covers a large array of devices. The HID specs defines a 32 bits "usage" identifier supporting up to 4 billion different types of HID devices, although only a fraction of those values have been assigned so far.
The Windows API you'll probably need is Raw Input. Unfortunately, this is not an interface for the programming illiterate.
I can offer some helpful links.
The scales use the "HID point of sale" USB spec, a link to which can be found in the comments section of the blog post I mention below. I'd link direct, but the spam prevention mechanism prevents me.
There's a blog post on addressing the 25lb version of the scale from C#, here: http://nicholas.piasecki.name/blog/2008/11/reading-a-stamps-com-usb-scale-from-c-sharp/
The comments on that post are helpful - that's where you find the USB spec, there's also a comment showing how to get at the data without using the full HID library.
Good luck with your project!
For USB devices not supported directly by the O/S, you either need to be a programmer, or you need a program supplied by the device vendor. In this case, as it sounds like you're not a programmer, you should contact the manufacturer to see if they can provide any diagnostic or testware programs that could be used to read and capture the scale data. If you're lucky, such a program can be "batched" and it's output redirected, or something like that. Good luck.
Thanks for the details Bob. Are there any scales you can recommend that have a max weight around 50 pound? I need something that is directly supported by the O/S. I want to be able insert a weight value into a web based form.
Elane sells a line of USB HID scales and also has a Windows program to read the weight. Unfortunately, because of Stamps.com, that program is no longer free. At $15.50, it's not necessarily something I'd want to blindly try, but here it is: http://www.elane.net/index.php?go=USB_pcsoftware