[Robotgroup] Low cost Radio control system..?

[Paul Atkinson]

I have flown R/C aircraft for a number of years and they usually tolerate
multiple transmitters well. We used to try and use every other channel. That
is have at least 1 unused channel between the channels we used. Since that
time, most of the R/C transmitters and receivers have gone to a "narrow
band" frequency filter that should safely allow the use of every channel
simultaneously.

There have been situations where 1 or 2 channels at a site were un-useable.
This varies by location, but it could be caused by harmonics due to pager
towers, cell towers, airport beacons, and medical equipment. I only mention
this because I have seen things tested in one location that did not function
in another location.

One more recent problem has been industial complexes which have
radio-controlled gantry cranes which are on the same frequencies as some of
the hobby channels. The industrial radio is higher powered, so it can
clobber hobby use in close proximity. The bad thing is that hobby use might
cause the crane to move or receive interference.

Hopefully none of thses issues will have any impact on your efforts.

Paul

On 4/23/07, thecomers at juno.com <thecomers at juno.com> wrote:
>
> I ordered one of the 72mhz Cirrus receivers to see if it will work
> with the Vex transmitter and the 75mhz/Channel 61 crystal.
>
> So assuming it works, my next question is:
>
> What if I have 2 Vex transmitters and 2 Cirrus 72 mhz receivers, and
> I am using:
> 75mhz/Channel 61 crystal (75.410 mhz)
> 75mhz/Channel 65 crystal (75.490 mhz)
>
> I wonder how well the radios will work. Or what if I have 9 robots? I
> may need to just take this one step at a time.
>
> Thanks,
> Bob Comer
>
>
>
> -- "thecomers at juno.com" <thecomers at juno.com> wrote:
> Thanks to Paul and Vern for your responses. I noticed there was a
> note on the All Electronics site where someone had tested the Vex
> transmitter with Futaba receivers, but it did not say if they were
> 75mhz receivers. So I assume that the Vex transmitter should work
> with my 75mhz Futaba receiver. But on the Tower Hobbies web site it
> looks like I would have to pay $59 for another 75mhz Futaba receiver.
> $20 sounds a lot better. I think I will order the Cirrus receiver and
> check it out.
>
> Bob Comer
>
> -- 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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