Newsgroups: comp.robotics
Path: brunix!news.Brown.EDU!noc.near.net!howland.reston.ans.net!gatech!cc.gatech.edu!doug
From: doug@cc.gatech.edu (Doug MacKenzie)
Subject: Re: Cheap DRAM cameras?
Message-ID: <1993Nov5.174239.6943@cc.gatech.edu>
Sender: news@cc.gatech.edu
Organization: College of Computing, Georgia Tech
References: <2b692b$2v7@news.u.washington.edu> <2b9si8$b8r@constellation.ecn.uoknor.edu>
Date: Fri, 5 Nov 1993 17:42:39 GMT
Lines: 44

In article <2b9si8$b8r@constellation.ecn.uoknor.edu>,
Robert W Murphree <rwmurphr@midway.ecn.uoknor.edu> wrote:
>ptorre@hardy.u.washington.edu (Phil Torre  KB7ZFH) writes:
>
>>I was trying to think up a sensing device for *cheap* homebuilt robots
>>that would give more/different information than IR or ultrasonic sensors,
>>and recalled that years ago (early '80s) people started cutting the
>>tops of of dynamic RAM chips and using the die as a cheap CCD image
>>detector.  I know this was done, but can't remember where I might have
>>read about it.  If anyone can remember a reference or has more info on
>>how this was done, please email me or post; this should be of interest
>>to all amateur robot builders (like me) for whom a fresh spool of solder
>>is a significant cash outlay!  :(
>
>all I know is the guys at Georgia tech in the m.e. department had
>a landmark finding camera that used the DRAM method. 

First, look at the small B/W cameras available.  There are several now in
the $100-$200 dollar range.  Look at adds in the back of Circuit cellar Ink.

If you really want to build a camera, I would look at the TI CCD chip TC-211
(number from memory...).  It is quite easy to interface.  I have seen one
mounted to a 68332 with just an op-amp, an A/D, and a delay line.
The chip is an 8 pin dip with an image array window.
The chip provides B/W with around 248x132 pixels.  The idea is that you
sub-sample the image by only digitizing every 4th pixel and every 4th row
to reduce component cost as well as make it possible to use the image in
a small system.  64 pixels wide by 32 pixels high with one byte
grey scale per pixel provides supprisingly good information for navigation.
BTW, the CCD chip is around $18 last time I looked.

P.S.,
This is also the chip used in the ME cameras as of a year ago.  The vision
stuff has been split off into a company called Dickerson Vision Technologies.
They currently sell systems for inspection tasks.


		Doug
*****************************************************
Douglas C. MacKenzie               doug@cc.gatech.edu
Ph.D. Research Assistant in the Mobile Robotics Lab.
College of Computing, Georgia Institute of Technology
Atlanta, Georgia 30332-0280
Lab phone: (404)-894-9311         Fax: (404)-853-9378
