Newsgroups: comp.robotics
Path: brunix!news.Brown.EDU!agate!howland.reston.ans.net!europa.eng.gtefsd.com!uunet!hearst.acc.Virginia.EDU!murdoch!galen.med.Virginia.EDU!dcw8e
From: dcw8e@galen.med.Virginia.EDU (David Collin Williams)
Subject: CDC cameras
Message-ID: <CGpxwH.5A@murdoch.acc.Virginia.EDU>
Sender: usenet@murdoch.acc.Virginia.EDU
Organization: University of Virginia
Date: Fri, 19 Nov 1993 03:05:05 GMT
Lines: 13

Cc: 

Recently, there has been some discussion about using the Texas Instruments
Tc211 ccd to develop a low-cost video camera. I have a few questions and comments. 
  Potentially, the Tc211 could bring low-cost video to robotics. The chip itselfis $35 (from Allied Electronics) and offers a little under 32k pixels. TI offerssome support chips, but recent postings indicated that the timing inputs could  produced by a microcontroller. The TI area sensor array handbook offers a schematic that has the tc211 outputing to a 6-bit flash a/d converter. I see a few
problems, though. First of all, it looks difficult (at least to me) to design
a circuit that would allow the ccd to adapt to different light levels typically encountered with mobile robots.  The light exposure is set be controlling the length of the sampling pulses, but I don't see how the pulses can be matched to 
external light levels without getting really complicated. Secondly, the TI
specs indicate that pixels have to be discharged into the analog shift register in DARK conditions, indicating the use of a shutter.  Working models have been
used without shutters though, so I suppose this obstacle can be overcome.
   In any case, a book is coming out in Jan 94 that describes how to design cameras with the tc211 and other TI CCD's. (Willman Bell publishers of Richmond, Va.1-800-320-7016). A recent posting also mentioned a company producing a kit--doesanyone have the phone# and address?
   Lastly, maybe the best way to go in the end would be with comercially available CCD cameras( now $170 from many sources) and a simple frame grabber that could be based on the new lm1881 sync. separator chip.
 
