FYI, the DRAM camera. When I worked for TI, I worked in the Failure Analysis group of the Engineering Dept. As an exercise in decapping IC's, we took a DRAM chip (IIRC a 4164) and decapped it. When we hooked up the=20 IC to the tester, we could see the lines wiggling, and made several recordings of the resulting data. We then Tried to process it to make an intelligible image from it, but because we had no lenses on the thing, there was No real discernable image. But you could tell there was something there. Looking at a few of the post processed=20 Records, you could see changes that appeared as though there was something moving. But you couldn't make out What it was that was moving. Anyway, the bottom line is a DRAM as a camera works. Not optimally, but it works. It is basically a CCD type sensor. With lenses and some processing H/W, it would be a reasonable, low cost camera for experimentation. However, not that Most basic digital cameras, and webcams are so inexpensive, it really doesn't make a lot of economic sense to try it. Regards, Jim -----Original Message----- From: piclist-bounces@MIT.EDU [mailto:piclist-bounces@MIT.EDU] On Behalf Of Matt Callow Sent: Thursday, August 05, 2010 9:33 PM To: Microcontroller discussion list - Public. Subject: Re: [OT] Setting the record straight 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 Electronic >> > Research Labs in Cambridge MA in the mid to late 1990s. =A0You may remember >> > 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 getting the lid off to see the chip was easy enough, and required triple supplies. There were problems though, you couldn't just step through the address to get the next pixel. The address lines were 'randomly' arranged i= n their 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, bu= t not one that made sense to human eyeballs. I guess someone worked out a clever scheme to do this using vertical, horizontal and diagonal lines unti= l they 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 packag= e as they were not as fine geometry, so may have had a better aspect ratio. 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 here: 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 --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .