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From: dpalmer@csuohio.edu (Darryl Palmer)
Subject: Re: REQUEST: Simple Sing
Message-ID: <1994Jul18.175119.8340@news.csuohio.edu>
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Date: Mon, 18 Jul 1994 17:51:19 GMT
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Henry Liu (henry.liu@tabb.com) wrote:
: I'm very interested in this.  I'd like to be able to transmit 2 anlogue and 
: 2 digital lines.  Do you think it could do this?  If not do you know of 
: anything/anyways to do this.  Your help will be greatly appreciated.
: ttyl
: Henry

: Henry Liu (henry.liu@tabb.com)
: ---
:  * WaveRdr 1.10 [NR] * UNREGISTERED EVALUATION COPY

Hmmm, let's see.  On the receiver you have 4 data pins plus the relay output
that is only closed when it receives the proper ID code.  So you have a
pseudo 5 data pins to work with.  The data pins can be transmitted using
2 of the 4 data pins.  For the analog transmission, you can get one of those
A to D convertors with a serial output (I have to check at school about
what the part# is) then all you have to do is turn the power on and off the
transmitter for a clock.  Each time you turn the power on and off, it will
toggle the output to the relay which you use as you clock pulse for your
serial data transmission for the A/Ds.  Depending on if you really want 
analog on your board, you just put on two D/As.  So for the transmitter
you will need two serial D/A convertors, a 12V battery for the power
(Standard lighter battery from Radio $hack), a controller or clock driver
for the conversion of the A/D and to control the power to the transmitter,
and maybe 2 small power/signal transistor (Although maybe on of those cool 
reset chips will due) for turning the power on and off. On the receiver you
will just need some D/As (If you really need analog on both ends), and use
the relay output as a clock pulse.  

As I said in previous postings, the actually latching of the data does not
occur until there is a valid ID code that is stable.  Under short distances
like 20 ft. you are not going to have a problem with getting maybe 30+
transmissions a second (which is about 3-4 real transmissions when you
consider a 6 bit A/D conversion).  The more noise or longer distance, you
will have to make a 1/2 or full wave antenna for the receiver and maybe a
real antenna for the transmitter (it currently uses a pcb trace).

So to answer all of the questions:
1) Could you use it? Yeah it should work, but some people also said that
   about cold fusion in a jelly jar.
2) How do you do it?  Along the lines of what I said above, but the only
   limit is your analog resolution and whether you have to modify the
   antennas.
3) Are their any better ways?  You might find something with two-way
   communication or error-checking (I remember someone mentioning 
   wireless modems were used for field work at LTV steel, because they were
   afraid of being vaporized by molten steel or some wimpy stuff like 
   that :) ).  If you need error checking you could have that transmitted
   after the data was sent if only 1 or 2 transmission per second is required.


Darryl Palmer
dpalmer@denning.csuohio.edu
