Newsgroups: comp.robotics
Path: brunix!sgiblab!darwin.sura.net!howland.reston.ans.net!torn!nott!cunews!freenet.carleton.ca!FreeNet.Carleton.CA!aa674
From: aa674@FreeNet.Carleton.CA (Martin Darwin)
Subject: Re: Stamp Kit experience
Message-ID: <Cu2sC0.50B@freenet.carleton.ca>
Sender: news@freenet.carleton.ca (Usenet News Admin)
Reply-To: aa674@FreeNet.Carleton.CA (Martin Darwin)
Organization: The National Capital FreeNet
References: <Ctz9Fv.3Lz@world.std.com>  
Date: Fri, 5 Aug 1994 18:50:24 GMT
Lines: 40



In a previous article, sje@world.std.com (Steven J Edwards) says:

>
>2) Ability to read a 0.1uF/CdS (photoresistor) series circuit sensor
>into an input pin; the resistance will vary from about 5 Kohm to 25
>Kohm.

	If your photoresistor has the right resistance ie. between
5-50Kohm it should work fine.  I have some cds cells that go from 2-120K
so unfortunately when it gets to dark it reads 0 instead of 255 (it could
be the other way around I don't remember).  What seems to happen is that
the pot command overflows.  I have be unable to get rid of this using the
scale part of the pot command.  Anyone have any suggestion on how to keep
the cds cell within the 5-50kohm range let me know. 

>
>3) Ability to do the photoresistor sampling at a rate of 5 Hz or
>better (I assume the CsD has a fast enough response time and that the
>"pot" command will work properly).

It should work.

>
>4) Ability to to reliable serial I/O to the computer.

I have just started trying to do serial communications with my pc. The
only problem that I have discovered is that the stamp doesn't pass over
the serin command if there is no data present, instead it waits until the
data comes in, which means events on other i/o pins could be lost.  I would
rather have the stamp use an On Com command like in gwbasic.

MD

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Martin Darwin, aa674@Freenet.carleton.ca (Ottawa,Ontario,Canada)  
