[Robotgroup] Low cost Radio control system..?

[Paul Atkinson]

Bob,

I know from previous R/C aircraft experience that changing crystals can
require re-tuning the receiver. That's something that has to be done at an
authorized service center usually. Given the proximity of the crystal
frequencies you have mentioned, I expect this wouldn't be required. It's not
like your robot will fall out of the sky if something isn't right.

Also, there are various schemes where the transmitted signal is sent on the
high or low side of the main frequency. Usually you have to be careful that
the receiver behaves the same way. The previously mentioned receiver states
that it can handle this. So, you ought to be ok on both counts. And since
Vern said someone already tried this sucessfully, you should be good to go.

I pointed out the issues in case anyone considers using a different
receiver.

Paul

On 4/20/07, Vern Graner <vern at txis.com> wrote:
>
> The forum was the R2D2 builders mailing list. The person who pointed it
> out was telling about his personal experience using it and that it had
> worked for him using the 75mhz crystal. :)
>
> Vern
>
> thecomers at juno.com wrote:
> > Vern:
> >
> > The Vex transmitter operates at 75mhz (frequency for ground
> > vehicles). The receiver that the link points to operates at 72mhz
> > (frequency for air vehicles). Do you (or anyone else) know if the
> > receiver will work with a 75mhz crystal? Or does the forum you looked
> > at talk about this issue?
> >
> > Thanks,
> > Bob Comer
> >
> > -- Vern Graner <vern at txis.com> wrote:
> > Ok, so the VEX radio remote transmitter is available here:
> >
> > http://www.allelectronics.com/cgi-bin/item/JS-6/search/6-
> > CHANNEL_TRANSMITTER_AND_RECEIVER_.html
> >
> > the issue is that the the included VEX receiver won't directly
> > control
> > servos w/o it's output being interpreted by a microcontroller (as
> > Gray
> > for details).
> >
> > So, a post on another forum claims success using this receiver with
> > the
> > VEX transmitter to control up to six servos:
> >
> > http://www.hobbypeople.net/gallery/443536.asp
> >
> > Should but your total cost for a 6 channel radio setup at about
> > ~$55.00 :)
> >
> > Vern
> >
> >
> >
> > ------------------------------------------------------------------------
> >
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>
> --
> Vern Graner CNE/CNA/SSE    | "If the network is down, then you're
> Senior Systems Engineer    | obviously incompetent so why are we
> Texas Information Services | paying you? Of course, if the network
> http://www.txis.com        | is up, then we obviously don't need
> Austin Office 512 328-8947 | you, so why are we paying you?" (c)VLG
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