Re: TI-H: RF Linking


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Re: TI-H: RF Linking



I have an idea for calculator comunications over an RF link.  First off
I will admit I am not an EE so if you will flame me for being wrong
please stop reading now.  OK now that half the list is gone.  Think of
this in the abstract for a second we have two lines.  However the
sending calc will only pull one low and the reciever will pull the
other.  So could we, using a Pic or something like that (maybe attach
one to an expander, I think pics are cheap anyway) Set a device up that
would set up two frequencies (maybe have a number of presets for
multiple different communications).  One calculator would use on the
other the other one.  After this is done the two links set up a constant
communication using some tone (very high pitch or something that would
not usually be transmitted).  When a calculator felt one of its lines
pulled low it could stop sending the tone very briefly how briefly would
depend on the wire that was pulled.  The other calculator would detect
this and pull the appropriate wire low and stop transmitting its tone
very briefly.  The nano second that the originating side detects this
interuption it pulls the opposite of the original line low and turns on
its singnal untill the other turns its on (when the original turns off
its signal for the second time the reciver calc would reset.) at wich
points it resets for the next transmition.
	The only problem I can see with this design is that I do not know how
long it will take for the pics and transmitters to do the work.  The
calc might time out to soon.  However I think that by sending a constant
signal we won't have to worry about interference to much.
	Well I would try to build this but I do not have a Pic programmer (or
the cash to buy one) so I hope that this helps some of the creative
people out there.  Good Luck!

--- Adam Kavan
--- akavan@cse.unl.edu

P.S.  If you did read this and feel that you need to flame me for being
an idiot feel free however please send it to me and not the list so we
can keep the discusion here a little more intelectual.


P.P.S.  Please excuse all spelling mistakes!


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