Subject:
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Re: RF Module
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Fri, 10 Sep 1999 14:18:00 GMT
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Original-From:
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Michael N Rosenblatt <(mr4@)stopspammers(andrew.cmu.edu)>
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Viewed:
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1022 times
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Hi, Sorry I didn't get back to you yesterday.
It sounds like you need to tune your radio modules. It could be your
transmitter, receiver or both. If you don't have a function generator to
create an input square wave for testing, you could try to get a timing
pulse off the Handy Board somewhere. The servo libs pulse at about 50 Hz
(I think) which is likely to be too slow for the radio modules. You
really need something in the 300 Hz to 1400 Hz range, and close to 50%
duty cycle. There is a timing signal to the motor driver chips, but I'm
not sure what the frequency is. (does anyone have this info?)
The reason why is is difficult to tune the modules off the pulse created
by the encoder board is that it transmitts in packets (I think it's a 12
bit word repeated 3 times per packet). There is lots of time, between
packets, you really need a constant input signal.
Once you have an input wave set up, watch the data out of the RE module on
your scope and tune the cap. the modules come pretty reliably tuned from
the factory, so if you have any that that have not been adjusted, you
should start by using that to first tune one module, and then tune the
other (if you have a new transmitter, use it to adjust your receiver...)
good luck,
Michael
On Thu, 9 Sep 1999, KwangJu, Lee wrote:
> Thanks your advice.
> But I have trouble still.
>
> I've confirm the encoder/decoder operation as you said. They works well.
> But radio modules, don't work.
> I assemble transmitter and encoder board, and confirm wave signal on the data in pin
> with my oscilloscope. But I check the data out pin on the receiver board, it just
> stay at HIGH - 5V always. I checked the V+ and GND pin, and it reports 5V and 0V, each.
> How can I repair it? I connect antenna ground pin to the receiver module ground, and
> antenna pin to 30cm jumper wire of 28 gauge.
>
>
> ----- Original Message -----
> From: Michael N Rosenblatt <mr4@andrew.cmu.edu>
> To: KwangJu, Lee <kjlee@scai.snu.ac.kr>
> Cc: Handyboard <handyboard@media.mit.edu>
> Sent: Thursday, September 09, 1999 1:39 PM
> Subject: Re: RF Module
>
>
> >
> > Hi.
> >
> > Have you tried attaching the data out (middle pin on three pin header)
> > from the encoder board to the data in (also middle pin on three pin
> > header) on the decoder with a common ground to each? This will allow you
> > to test the encoder/decoder boards without the radio modules.
> >
> > As for tuning the variable capacitor on the transmitter and receiver
> > boards, the best way is to set up a 0-5v square wave ~1KHz on a function
> > generator and plug it into the data in of the transmitter. Supply power
> > and ground to each (doesn't have to be common) and watch the data out on
> > your scope. Play with the tuning until the wave is noise-free.
> >
> > Now, backing up, you realize that you can't use the encoder/decoder boards
> > to replace the wire serial connection to the computer? If you have a way
> > of controlling the 4 digital input lines on the encoder board from your
> > computer, and you read the 4 output lines on the decoder with the HB's
> > digital ports, you could establish control from your PC (or alternatively,
> > you could put switches on the encoder board and control it directly,
> > manually). However, I'm pretty certain that the internal protocall of the
> > encoder/decoders, and the baud rate would prevent it from working as a
> > download cable replacement. Let me know it you find this to be wrong, as
> > the Ming boards are a great low-cost RF item.
> >
> > best,
> > Michael
> >
> >
> > On Thu, 9 Sep 1999, KwangJu, Lee wrote:
> >
> > > I'm trying to attach RF module to my handy board.
> > > I purchased the modules from MING system, - RE-99, TX-99,
> > > RE-01, TX-01.
> > > I want to set up communication between Handy board and IBM-PC
> > > using these modules. So I assembly the modules, but they don't work.
> > > I test the encoder/decoder board and they operate well.
> > > But I attach the receiver module, it can't get signal from transmitter module.
> > > I guess the transmitter board may be works well since I check it with oscilloscope.
> > > But however I adjust the variable capacitor on the receiver board, the relay
> > > on the encoder board doesn't response. The only time the receiver board response
> > > is when I connect the antenna ground pin to the transmitter's ground.
> > > How can I let them work?
> > >
> > >
> >
> >
> >
> >
> >
>
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