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Optical Mice as Cheap Barcode Scanners?
Ikester asks: "I've been evaluating a couple of barcode scanners including the CueCat (which some of you may recall from the failed off- online marketing stint by Digital Convergence) for a cataloging application. However, getting ahold of these 'free' wands is not that easy these days and it occurred to me that an optical mouse's hardware may be able to perform a similar function with the right mouse driver. For example, it could work as a regular mouse until it 'recognizes' a valid barcode. It could then send the code as if the user had typed it. I Googled the web and newsgroups but I didn't find anything relevant. I'm wondering if anybody from the Slashdot crowd has come across such an approach. With the recent proliferation of optical mice I'm thinking this could be the next best input device for linear barcodes. I have limited knowledge about mouse drivers and the actual design of these mice. Is this even possible?"
Too baad optical mice don't send back data telling the computer the "color" or "opacity" of the serface they are on, they just tell the computer how long it stayed in the same place.
Think about it... when you plug in an optical mouse, you don't need a special driver. So all the optical vs. wheel circuitry must be in the mouse, not the driver. All the mouse is sending over the USB cable is position information, same as a wheeled mouse. All the "take a picture and evaluate the changes" happens inside the mouse.
As a side note, I'll sell you my Cue Cat for $50.
_sig_ is away
How does an optical mouse work
I doubt this could be done (at least with any kind of reliability) at the driver level. It definately could be done with a little creative rewiring, but I would not be the right person to ask how to actually accomplish this.
Thoughts on tech, Software Engineering, and stuff
It takes an image/picture from 300-1000 times per second, runs an algorithm looking for significant features on a very small pixel area, and compares. Very little detail is required to actually work as any contrast at all is enough. (between 2 or more frames)
check out SDLcam. I haven't used it yet but it looks sweet.
Screen Shot
It's a nice idea... Unfortunately, optical mice do all their processing onboard. They don't send any raw data to the PC. I also doubt any use flash memory, and so are capable of a firmware upgrade; and even if they were, it's unlikely they'd have sufficient space to be able to handle both tasks. I suppose the right firmware could make the mouse simply dump raw data upstream and let your PC do the decoding, but that'd also make it incompatible with regular mouse drivers.
You can get a Modified CueCat for pretty cheap on ebay. They plug into your PS2 port and type out the bar code as plain text as soon as you swipe somthing. No special driver needed, your computer thinks its just a keyboard.
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