DTMF Tones
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Hello,
I was trying to build a small toy RC blimp and then saw how
expensive the transmitter and reciever were. Then I had this weird
idea. If I had a DTMF tone encoder hooked up to a CB radio's mic, and
a tone decoder attatched to another CB's speaker, then had a Basic
Stamp2 on the decoder to tell the blimp what to do, would that work?
Lets say you pushed the number "1" on the encoder. The tone it made
would go to the CB and get transmitted. Then the other CB would
recieve it and the decoder would give it's output in a 4-bit
hexadecimal code. Next, the BS2 would output a signal to a relay
which in turn would operate a fan to make the blimp turn left. Does
anyone have a clue whether this would work or not?
-Thanks
I was trying to build a small toy RC blimp and then saw how
expensive the transmitter and reciever were. Then I had this weird
idea. If I had a DTMF tone encoder hooked up to a CB radio's mic, and
a tone decoder attatched to another CB's speaker, then had a Basic
Stamp2 on the decoder to tell the blimp what to do, would that work?
Lets say you pushed the number "1" on the encoder. The tone it made
would go to the CB and get transmitted. Then the other CB would
recieve it and the decoder would give it's output in a 4-bit
hexadecimal code. Next, the BS2 would output a signal to a relay
which in turn would operate a fan to make the blimp turn left. Does
anyone have a clue whether this would work or not?
-Thanks
Comments
>Hello,
> I was trying to build a small toy RC blimp and then saw how
>expensive the transmitter and reciever were. Then I had this weird
>idea. If I had a DTMF tone encoder hooked up to a CB radio's mic, and
>a tone decoder attatched to another CB's speaker, then had a Basic
>Stamp2 on the decoder to tell the blimp what to do, would that work?
>Lets say you pushed the number "1" on the encoder. The tone it made
>would go to the CB and get transmitted. Then the other CB would
>recieve it and the decoder would give it's output in a 4-bit
>hexadecimal code. Next, the BS2 would output a signal to a relay
>which in turn would operate a fan to make the blimp turn left. Does
>anyone have a clue whether this would work or not?
Probably not as nicely as the proportional control typical of the more
expensive RC systems. A homegrown control system is also likely to weigh a
lot more than a commercial RC system, and I think weight will be a very
important consideration for you. But in the final analysis, it would be
illegal to use CB frequencies, even the ones located between the regular CB
channels that are meant for RC control, for control of a flying
machine. The CB RC frequencies are for control of ground operated devices
(cars, etc.) only - by Federal law. Also, there is enough illegal voice
operation on the CB RC frequencies by CBers that you could be subject to
considerable interference. Loss of control of a flying machine represents
a safety risk - even if less for a blimp than for a faster moving fuel
powered device. I don't see any plusses at all to this approach.
Jim H
make sure you do not start the construction of this project until you
measure the size of the blimp! helium has a very low density and the tiny
hobby blimps like the one I have will only lift a few ounces/lb of helium
used. I have a 3 foot unit and it just barely lifts a tiny cmos camera and
tiny transmitter with the battery for the r/c and the little engines with
ducted fans I put on it. Your idea has merit for control, but I think the
letters "GOODYEAR' will have to appear on the side for you to get off the
ground. I used to work on the Goodyear blimp in N.C. with some imagery
projects and we even had to be very careful with weight of rack equipment
with the big ones as the density to air-helium and weight was very critical.
I hope I did not burst your bubble, but these are proven facts from
experience. If you need any more info, I have a friend who is head of the
West Jersey R/C club who worked for me that knows all about this and is 80
years old with one eye and still flies model helos like a champ. He would
be happy to give you more info if you want to e-mail him
mike mocenter
Original Message
From: <sjohns10@h...>
To: <basicstamps@yahoogroups.com>
Sent: Saturday, June 16, 2001 10:13 PM
Subject: [noparse][[/noparse]basicstamps] DTMF Tones
> Hello,
> I was trying to build a small toy RC blimp and then saw how
> expensive the transmitter and reciever were. Then I had this weird
> idea. If I had a DTMF tone encoder hooked up to a CB radio's mic, and
> a tone decoder attatched to another CB's speaker, then had a Basic
> Stamp2 on the decoder to tell the blimp what to do, would that work?
> Lets say you pushed the number "1" on the encoder. The tone it made
> would go to the CB and get transmitted. Then the other CB would
> recieve it and the decoder would give it's output in a 4-bit
> hexadecimal code. Next, the BS2 would output a signal to a relay
> which in turn would operate a fan to make the blimp turn left. Does
> anyone have a clue whether this would work or not?
>
> -Thanks
>
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station by DTMF codes. Don't remember what frequency band they were
using.
> Then I had this weird
> >idea. If I had a DTMF tone encoder hooked up to a CB radio's mic, and
> >a tone decoder attatched to another CB's speaker, then had a Basic
> >Stamp2 on the decoder to tell the blimp what to do, would that work?
The Sky Surfer powered paragliders come with a 27Mhz band r/c set-up.
>. But in the final analysis, it would be illegal to use
> CB frequencies, even the ones located between the regular CB channels that are
> meant for RC control, for control of a flying machine. The CB RC frequencies
> are for control of ground operated devices (cars, etc.) only - by Federal law.
> Also, there is enough illegal voice operation on the CB RC frequencies by
CBers
> that you could be subject to considerable interference. Loss of control of a
> flying machine represents a safety risk - even if less for a blimp than for a
> faster moving fuel powered device. I don't see any plusses at all to this
> approach.
>
> Jim H
extra security code on it and not CB frequencies?
>I saw where a camera system on a full size heli was controlled from the
>station by DTMF codes. Don't remember what frequency band they were
>using.
Control of a camera and control of the heli(copter?) itself are two
entirely different things. The latter is illegal, and irresponsibly
dangerous, if done on USA CB RC frequencies. If the original writer was in
the UK, or elsewhere where laws may be different, it wasn't mentioned, and
wasn't apparent from his Hotmail address.
> > Then I had this weird
> > >idea. If I had a DTMF tone encoder hooked up to a CB radio's mic, and
> > >a tone decoder attatched to another CB's speaker, then had a Basic
> > >Stamp2 on the decoder to tell the blimp what to do, would that work?
>
>The Sky Surfer powered paragliders come with a 27Mhz band r/c set-up.
The only Sky Surfer powered paraglider I know comes with a SkySport 4
radio, which is a 72/75 MHz narrow band FM radio, not a 27 MHz AM radio as
used on the USA CB bands. Are there perhaps several different Sky Surfers,
or several different Sky Sport 4 radios? The CB band, in the USA, runs
from just below 27 MHz to about 27.4 MHz, and it is AM, not FM. My fault
for saying "Federal law" rather than "USA Federal law."
> >. But in the final analysis, it would be illegal to use
> > CB frequencies, even the ones located between the regular CB channels
> that are
> > meant for RC control, for control of a flying machine. The CB RC
> frequencies
> > are for control of ground operated devices (cars, etc.) only - by
> Federal law.
> > Also, there is enough illegal voice operation on the CB RC frequencies
> by CBers
> > that you could be subject to considerable interference. Loss of
> control of a
> > flying machine represents a safety risk - even if less for a blimp than
> for a
> > faster moving fuel powered device. I don't see any plusses at all to this
> > approach.
> >
> > Jim H
Jim H
>Would it still be illegal to use those little walkie-talkies with the
>extra security code on it and not CB frequencies?
Yes! It is illegal, in the USA, to use RC control systems to control
flying machines that are not meant specifically for the control of flying
machines. It is also irresponsibly dangerous. You need to focus firmly on
the latter.
Walkie talkies are subject to interference by similar walkie talkies, which
can result in loss of control of the flying machine with risk of injury and
property damage. Even with a security code - and it sounds like you might
be talking about walkie talkies used in the Family Radio Service here -
signals from other FRS radios can block your control signals even if they
don't use the same security code as you do. The security codes on FRS
radios only control the squelch. So signals from another FRS radio on the
same frequency as yours can still block your receiver even though the
security code is different. You just won't hear the other signal because
its security code won't open the receiver squelch control. These are FM
radios, so the strongest signal will capture the receiver. You can't be
sure you will always be the strongest signal.
You need to get in touch with a local RC hobby shop where you can probably
get all your questions about RC answered - technical and legal. You will
quickly find that most RC enthusiasts will turn you in in a second if they
catch you using an illegal control transmitter.
Jim H