From: "Jinx" <joecolquitt@clear.net.nz>


>> Apparently they have investigated using a camera in a box, hung on the
>> front of the dairies display, and then using an OCR program to identify
>> the number
>
> Roger, I've tried reading an LCD optically (not a camera). It's not easy
> or reliable. A lot of unwanted reflection and difficult to pick up 
> individual
> pixels

That was my worry too. I know they were using a closed-in box to exclude 
unwanted light, but it sounds difficult to do in an ideal environment, let 
alone a dairy :) Especially a different one every day.

>> I suspect the best way would be to 'crack' the communications feeding
>> from the reader to the display, though exactly how to do that is my
>> dilemma
>
> That sounds like a better plan, but how it's done would depend on the
> strength (impedance) of the signal and what sort of radiation you can pick
> up. My first approach would be to try a sensitive Hall Effect sensor, to
> see if there's any readable electro-magnetism. If that's no good, perhaps
> a high-gain inductive voltmeter arrangement. If all else fails, is it 
> possible
> to interrupt the cable with a plug and socket and tap into the wire ?

Yes, it is possible to unplug the display and tap into the signal, so I 
still feel this would be the best approach. I just need a crash course on 
serial communications.

Thanks for your input.

Regards,  Roger



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