On 6 August 2010 00:02, wrote: >> On Wed, Aug 4, 2010 at 12:42 PM, Olin Lathrop wrote: >> >> >> In a related area, early video camera elements were made from DRAMs >> >> with out covers over the chips. >> > >> > I think that was a later development. =A0I'm reasonably sure using DRA= Ms as >> > image sensors was pioneered by Bill Yerazunis of the Mitsubishi Electr= onic >> > Research Labs in Cambridge MA in the mid to late 1990s. =A0You may rem= ember >> > him as "Crash" on the NERDS team of some Junkyard Wars episodes. > > I remember a colleague talking of doing this in the early 1980s, using a = 16k dynamic ram chip. They only came in ceramic packages at that stage so g= etting the lid off to see the chip was easy enough, and required triple sup= plies. There were problems though, you couldn't just step through the addre= ss to get the next pixel. The address lines were 'randomly' arranged in the= ir decoding to minimise inter cell cross talk inside the chip, so until you= worked out the cell to address line mapping you could get a picture, but n= ot one that made sense to human eyeballs. I guess someone worked out a clev= er scheme to do this using vertical, horizontal and diagonal lines until th= ey could get a perfect picture every time. > > Major problem was the chip was long and narrow, so the aspect ratio wasn'= t optimal. He may have also played with 4k chips which came in a wider pack= age as they were not as fine geometry, so may have had a better aspect rati= o. I remember seeing a design for a BBC micro camera using a DRAM in a UK electronics or computer magazine. At the time I though it looked really cool. I can't find any reference to it now, but I did find this: http://www.8bs.com/see/snapcam2.jpg Which is a picture of a commercially available camera for the BBC micro. There are some more pictures, including some images taken with the camera h= ere: http://www.8bs.com/seeimageinput.htm Matt --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .