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Subject: 
Re: IR to FM
Newsgroups: 
lugnet.robotics
Date: 
Sat, 2 Sep 2000 11:30:35 GMT
Viewed: 
1775 times
  
Hi,

Here is a link on ebay for the exact item I was talking about:

http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=424895386

Cheers,

Ram

----- Original Message -----
From: "Simon Bogaert" <lego-robotics@crynwr.com>
To: <lugnet.robotics@lugnet.com>
Sent: Thursday, August 31, 2000 6:12 PM
Subject: Re: IR to FM


> <snapped an excellent technical description>
> 
> > I have used a small 8051 (single chip) microprocessor to decode these • kinds
> > of signals in the past. I converted them into RS-232 so that I could • plug
> > this into a PC's serial port - which I used to drive a flight simulator
> > program that I'd written for a radio controlled model plane!
> > 
> > So it's certainly not impossible that you could do it in software inside
> > an RCX with the output of a radio receiver (appropriately
> > demodulated/amplified/attenuated/whatever) stuffed into one of the • inputs.
> > The RCX is quite a bit faster than an 8051 - so this shouldn't be too
> > hard.
> I wasn't exactly thinking of the RCX doing the smart job of the FM
> communication.  I imagined more of the RCX just outputting IR signals to • an
> apparatus that translates them to FM.  These radio waves are then picked • up
> by a second apparatus that translates the FM back to RCX compatible IR
> signals, thus enabling the two RCX'es to communicate outside the line of
> sight and on a greater distance.
> 
> > However, I do think you'd need to use a true machine-code/C approach • using
> > LegOS or something to do the decoding. The NQC byte-code wouldn't be • fast
> > enough - and the task scheduler would do bad things to your high • precision
> > timing.
> > 
> > Getting this to work would actually be rather cool - the radio system
> > could easily provide up to 8 analog/switched inputs using only one
> > RCX input.
> > 
> > On the other hand, any filtering/protection circuitry that Lego may
> > have hung off the RCX inputs might screw things up to the point where
> > you can't read the input signal anymore.
> Making an RCX the heart of radio comms is indeed a very interesting • project.
> 
> > Using one of the RCX outputs to drive a radio transmitter ought to
> > be possible too.  Some RC transmitters have an optional 'buddy box'
> > input that lets you slave one transmitter to another so that an
> > 'instructor' can take over and fly your model plane if you are
> > in danger of crashing it while learning to fly.
> > 
> > The buddy box input is in the same format at the RC output
> > signal - except that it's not FM or AM modulated.  Again, I'm
> > not sure what voltages you'd need - but in principle one
> > could connect the output of an RCX to the buddy box input via
> > some kind of signal conditioning and some careful timing
> > software and have a radio link!
> This also is a very interesting project!
> 
> > I considered doing this once before (but with a laptop's printer
> > port - not an RCX) - so I could teach my computer to fly
> > an RC plane...
> > 
> > ...but then sanity prevailed.
> > 
> >    :-)
> Which wasn't in-sane...
> 
> > ** WARNING WARNING WARNING WARNING WARNING WARNING WARNING **
> > 
> >      PLEASE DON'T DO THIS UNLESS YOU ARE FULLY AWARE OF
> >          THE
> > EXACT VOLTS, AMPS, OHMS, WATTS, HERTZ,
> >           BITS AND BYTES OF WHAT YOU ARE DOING!
> > 
> > If you do any of these things and wreck either the RCX, your
> > computer or your radio gear, I will not be accepting responsability!
> Of course not: doing anything with your RCX that's not in the book of
> correct use is at your own risk.
> 
> Don't stop constructring...
> 
> Simon



Message is in Reply To:
  Re: IR to FM
 
<snapped an excellent technical description> (...) kinds (...) I wasn't exactly thinking of the RCX doing the smart job of the FM communication. I imagined more of the RCX just outputting IR signals to an apparatus that translates them to FM. These (...) (26 years ago, 31-Aug-00, to lugnet.robotics)

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