Hi Kerry et al,

I read the pdf files you suggested, with great interest.  I appreciate=20
that you pointed me in this direction.

But, as I read through the articles, it became painfully clear that the=20
amount of logic needed to support any sort of a low resolution optical=20
device is staggering, even for a modest 128 by 256 pixel resolution.=20
And, the power usage is high enough so that stealth sensors becomes much=20
more difficult as well.

I think my project is a little more than I want to undertake at this=20
time. But, if I did undertake it, I think I'd use an FPGA to produce all=20
the digital support I/O for a dram type of optical sensor.

Thanks to all who gave me suggestions that I needed to conclude that the=20
project is much more complex and expensive than I originally thought it=20
would be.

This is a great list, I also want to thank those who make it possible to=20
continue.

Art

On 03/15/2013 11:16 AM, Kerry Wentworth wrote:
> If you want low parts cost and labor is free, you could pop the top off
> of a dynamic RAM chip and focus an image on to the die.
>
> Here are some articles describing the process:
>
> ftp://ftp.circuitcellar.com/pub/BYTE_Projects/D-Cam1.pdf
> ftp://ftp.circuitcellar.com/pub/BYTE_Projects/D-Cam2.pdf
>
> http://www.cs.uaf.edu/2007/fall/cs441/support/dram_sensor_1984_whitehead.=
pdf
>
>
> They use a special (expensive and unobtainable) chip, but since you
> don't actually care about the picture, you can just use any old dynamic
> RAM chip and a PIC.  Adjusting exposure time to keep the number of 'on'
> pixels the same should eliminate ambient light changes.  Then compare 2
> frames pixel by pixel looking for a threshold number of changed pixels.
> Parts cost should be under $5, design costs moderate to infinite.
>
>

--=20
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