EPROM erase times and lifespan

Dave Dunfield dave09 at dunfield.com
Fri Jan 30 17:20:27 CST 2009

> I remember one article that described an incredibly creative, low cost digital camera-like device.
> Instead of a CCD, the thing used an ordinary DRAM chip with the cover pried off. The light would
> affect the cells of the DRAM, and then the 'image' could be read by the computer. Of course, the
> thing was incredibly primitive - the pictures weren't great, but it was an ingenous hack, and a
> clever utilization of the light-sensitive nature of these things.

This topic seems to come up here every few years...

In case anyone wants it, I have a scan of a two-part 1983 Circuit Cellar
artical called "Build the Micro D-CAM" which is essentally this, except
that he uses the IS32 "Optic RAM" from Micron.

I have the datasheet for the IS32 scanned as well, which says "Improved cost
standards for binary image sensing (less than $.0003 / element) are delivered
through Micron's MT4264 64K dynamic RAM memory chip as the sensing device.
The OpticRAM(tm) image sensor is differentiated by packaging with a glass lid
(vs the opaque lid used in memory chips) and connection of the normally unused
pin 1 for optical threshold reference adjustment".

So they actually state that they are using their standard 64k DRAM as the
sensor, but it's not clear how modified it is ... ie: what are they doing with
pin1 at the die?).

I've also got a scan of a 1975 Popular Electronics artical titled "Build CYCLOPS
first all solid-state TV camera for experimenters" - it's not clear what he used
for the sensor, he just referrs to it as a "1024 element MOS sensor" and mentions
that it's packed in "a conventional 16 pin DIP". It's only a 32x32 display, and
he uses an oscilloscope for the display device...


dave09 (at)    Dave Dunfield
dunfield (dot) Firmware development services & tools: www.dunfield.com
com            Collector of vintage computing equipment:

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