On Sun, Dec 06, 2015 at 05:55:06PM -0800, Bob Blick wrote:
> I'm reverse engineering this candy dispenser in order to improve it:
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> http://www.bedbathandbeyond.com/store/product/sharper-image-reg-motion-ac=
tivated-candy-dispenser/204589
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> I'm using it as an indoor cat feeder, filled with kibble. It actually
> works pretty well out of the box. It only took a couple of days to teach
> the target cat to use it.
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> It's got a small PC board with discrete phototransistor and IR LED(set
> up as a reflective sensor), micropower 3.3V regulator, LM393 dual
> comparator, three transistors, assorted R's and C's, and an 8 pin SOIC
> with no markings.
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> The mystery chiip has ground on pin 8 and +3.3 on pin 1. So my first
> guess is a PIC12F508 or some other 8 pin PIC. But are there any other 8
> pin chips with power and ground in that configuration?

Bob,

My thought process is trying to track down the chip is a fools errand just
because there are so many chips that fit the description.

Is it possible to do a black box approach? Essentially there are only 6
pins to decode. Figure out which are inputs and outputs. Then use a logic
analyzer to grab the functional operation of the device.=20

At that point figure out if a PIC can mimic that operation. If so, then it
really doesn't matter what the original chip was since its functionality
was captured.

I hope I didn't miss some obvious flaw to this approach.

BAJ

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> Thanks, Bob
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> --=20
> http://www.fastmail.com - Same, same, but different...
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--=20
Byron A. Jeff
Associate Professor: Department of Computer Science and Information Technol=
ogy
College of Information and Mathematical Sciences
Clayton State University
http://faculty.clayton.edu/bjeff
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.