wireless serial Radio-Link

Take a look at this little nifty device:
http://www.nordicsemi.no/index.cfm?obj=product&act=display&pro=82

I should contain everything you will need for your telemetry/control of the
helicopter. (The 433MHz band in Europe is fairly open - but you will need to
check with the appropriate rules regarding control of toys)

The respons you are looking for, as in real time control of a RC Helicopter,
will not be detrimented by a turnaroundtime  less than 10ms. I believe that
low weight is more important that a couple of extra bytes in the protocol?

The range you want is  in the best conditions possible, you have practically
line-of-sight and a proper choice of antenna should give you the link budget
you want.

HTH

-- 
----
Morten
Raider of the Lost Electron

On Tue, 6 Jul 2004 08:31:06 +0200, "Raider of the Lost Electron"
<invalid@spam.no> wrote:

>I should contain everything you will need for your telemetry/control of the
>helicopter. (The 433MHz band in Europe is fairly open - but you will need to
>check with the appropriate rules regarding control of toys)

IMHO, anybody trying to use a shared frequency band for _control_ of a
model aircraft or other flying device should be put behind bars to
think what he/she is doing !!

If other legal signals on that frequency band disrupts the control
link for say, a few minutes, it is quite likely that the aircraft goes
out of control and may hit someone in the head with disastrous
consequences. 

For instance, if some LPD (10-100 mW) is used for a control link on
the 433 MHz band which is also used by radio amateurs, it is quite
likely, that the control link may be interrupted by amateur radio
transmissions, especially since the 433 MHz range is used for the
mobile to repeater transmissions in many countries. A mobile amateur
radio transmitter, which are typically 30-50 W or about 30 dB more
than the LPD, may block the control link when moving in the
neighbourhood.

Use proper frequency bands specially allocated for model control to
control the helicopter. 

Using some other band for telemetry will also solve the duplex
problem. If a shared frequency band is used, the downlink could suffer
interference from other legal users of the band, so this must be
considered, when designing the system.

Paul
   

On Tue, 06 Jul 2004 11:12:10 +0300, Paul Keinanen <keinanen@sci.fi> wrote:

[...]
> For instance, if some LPD (10-100 mW) is used for a control link on
> the 433 MHz band which is also used by radio amateurs,
[...]

As the OP wants to fly his model in the UK, it would be worth mentioning 
that Ofcom, the UK regulating body, has a dedicated band around 35 MHz for 
flying gadgets.  433 MHz can be used to transmit data *from* the model.  
Some more details can be foud here:

http://www.ofcom.org.uk/static/archive/ra/publication/ra_info/ra60.htm


HTH,
   Vadim

Paul Keinanen <keinanen@sci.fi> wrote in message news:<g1kke09t8dm5httfnt0to8ca5s290najpu@4ax.com>...
> On Tue, 6 Jul 2004 08:31:06 +0200, "Raider of the Lost Electron"
> <invalid@spam.no> wrote:
> 
> >I should contain everything you will need for your telemetry/control of the
> >helicopter. (The 433MHz band in Europe is fairly open - but you will need to
> >check with the appropriate rules regarding control of toys)
> 
> IMHO, anybody trying to use a shared frequency band for _control_ of a
> model aircraft or other flying device should be put behind bars to
> think what he/she is doing !!

You can't put someone in jail just for thinking of trying something.
He might own the entire 400 meters air and ground space.  Even if he
carry out the experiment and did some damages, he should be responsible
financially.  If he did not intend to cost such damage, he should not
be in jail.

I wonder how many inventors would carry out their experiments if they risk
going to jail for.


> 
> If other legal signals on that frequency band disrupts the control
> link for say, a few minutes, it is quite likely that the aircraft goes
> out of control and may hit someone in the head with disastrous
> consequences. 
> 
> For instance, if some LPD (10-100 mW) is used for a control link on
> the 433 MHz band which is also used by radio amateurs, it is quite
> likely, that the control link may be interrupted by amateur radio
> transmissions, especially since the 433 MHz range is used for the
> mobile to repeater transmissions in many countries. A mobile amateur
> radio transmitter, which are typically 30-50 W or about 30 dB more
> than the LPD, may block the control link when moving in the
> neighbourhood.
> 
> Use proper frequency bands specially allocated for model control to
> control the helicopter. 
> 
> Using some other band for telemetry will also solve the duplex
> problem. If a shared frequency band is used, the downlink could suffer
> interference from other legal users of the band, so this must be
> considered, when designing the system.
> 
> Paul

On 6 Jul 2004 09:31:24 -0700, me@linnix.info-for.us (Linnix) wrote:

>You can't put someone in jail just for thinking of trying something.

Like drinking a bottle of whisky and then driving around in a car
without brakes :-).

>He might own the entire 400 meters air and ground space.  

Depending of the sped of the model aircraft, it does not require a
long communication failure to fly outside even this area. 10-40 s
should be enough.

The situation for a model helicopter may be different _if_ the
helicopter goes into a autoratoation mode upon loss of command link
and lands more or less intact close to the point of communication link
failure.
 
>Even if he
>carry out the experiment and did some damages, he should be responsible
>financially.  

What is the price of a dead person ?

>If he did not intend to cost such damage, he should not
>be in jail.

I think "criminal negligence" is term used in the US.

My point is, why use a risky method, when there are other methods
considered to be more safe (frequencies allocated for model aircraft
control) ?
 
Paul

On Tuesday, in article <opsaptvmvsy1ubid@news>
     vadim.borshchev@127.0.0.1 "Vadim Borshchev" wrote:

>On Tue, 06 Jul 2004 11:12:10 +0300, Paul Keinanen <keinanen@sci.fi> wrote:
>
>[...]
>> For instance, if some LPD (10-100 mW) is used for a control link on
>> the 433 MHz band which is also used by radio amateurs,
>[...]
>
>As the OP wants to fly his model in the UK, it would be worth mentioning 
>that Ofcom, the UK regulating body, has a dedicated band around 35 MHz for
                                                                 ^^^^^^
Flying Gadgets MUST use 70MHz band, 40MHz is for land/water toys.
 
>flying gadgets.  433 MHz can be used to transmit data *from* the model.  
>Some more details can be foud here:
>
>http://www.ofcom.org.uk/static/archive/ra/publication/ra_info/ra60.htm
>
>
>HTH,
>   Vadim
>

-- 
Paul Carpenter		| paul@pcserv.demon.co.uk
<http://www.pcserv.demon.co.uk/>        Main Site
<http://www.gnuh8.org.uk/>              GNU H8 & mailing list info.
<http://www.badweb.org.uk/>             For those web sites you hate.

On 6 Jul, in article
     <b2278688.0407060831.57d4cfdc@posting.google.com>
     me@linnix.info-for.us "Linnix" wrote:

>Paul Keinanen <keinanen@sci.fi> wrote in message
> news:<g1kke09t8dm5httfnt0to8ca5s290najpu@4ax.com>...
>> On Tue, 6 Jul 2004 08:31:06 +0200, "Raider of the Lost Electron"
>> <invalid@spam.no> wrote:
>> 
>> >I should contain everything you will need for your telemetry/control of the
>> >helicopter. (The 433MHz band in Europe is fairly open - but you will need to
>> >check with the appropriate rules regarding control of toys)
>> 
>> IMHO, anybody trying to use a shared frequency band for _control_ of a
>> model aircraft or other flying device should be put behind bars to
>> think what he/she is doing !!
>
>You can't put someone in jail just for thinking of trying something.
>He might own the entire 400 meters air and ground space.  Even if he
>carry out the experiment and did some damages, he should be responsible
>financially.  If he did not intend to cost such damage, he should not
>be in jail.

There has been at least one court case after inquest in the UK of
model aircraft losing control and killing a small boy.

There is a web page about it on the Radio Control Modelling group site.

>I wonder how many inventors would carry out their experiments if they risk
>going to jail for.

They should always check what they are doing for safety and risk assessment
many don't.

-- 
Paul Carpenter		| paul@pcserv.demon.co.uk
<http://www.pcserv.demon.co.uk/>        Main Site
<http://www.gnuh8.org.uk/>              GNU H8 & mailing list info.
<http://www.badweb.org.uk/>             For those web sites you hate.

On Tue, 6 Jul 2004 23:05:02 +0000 (UTC), paul$@pcserv.demon.co.uk (Paul Carpenter) wrote:

>On 6 Jul, in article
>     <b2278688.0407060831.57d4cfdc@posting.google.com>
>     me@linnix.info-for.us "Linnix" wrote:
>
>>Paul Keinanen <keinanen@sci.fi> wrote in message
>> news:<g1kke09t8dm5httfnt0to8ca5s290najpu@4ax.com>...
>>> On Tue, 6 Jul 2004 08:31:06 +0200, "Raider of the Lost Electron"
>>> <invalid@spam.no> wrote:
>>> 
>>> >I should contain everything you will need for your telemetry/control of the
>>> >helicopter. (The 433MHz band in Europe is fairly open - but you will need to
>>> >check with the appropriate rules regarding control of toys)
>>> 
>>> IMHO, anybody trying to use a shared frequency band for _control_ of a
>>> model aircraft or other flying device should be put behind bars to
>>> think what he/she is doing !!
>>
>>You can't put someone in jail just for thinking of trying something.
>>He might own the entire 400 meters air and ground space.  Even if he
>>carry out the experiment and did some damages, he should be responsible
>>financially.  If he did not intend to cost such damage, he should not
>>be in jail.
>
>There has been at least one court case after inquest in the UK of
>model aircraft losing control and killing a small boy.

If you are referring to the accident in April 2003 on Dartford Heath in Kent
then the model was unsafe to fly in the first place and it had nothing to do 
with the quality of the radio equipment. It was the structural airframe that failed.

And it was a girl.

>There is a web page about it on the Radio Control Modelling group site.
>
>>I wonder how many inventors would carry out their experiments if they risk
>>going to jail for.
>
>They should always check what they are doing for safety and risk assessment
>many don't.

On Tue, 6 Jul 2004 23:04:59 +0000 (UTC), Paul Carpenter 
<paul$@pcserv.demon.co.uk> wrote:

>> As the OP wants to fly his model in the UK, it would be worth mentioning
>> that Ofcom, the UK regulating body, has a dedicated band around 35 MHz 
>> for
>                                                                  ^^^^^^
> Flying Gadgets MUST use 70MHz band, 40MHz is for land/water toys.

Any link?  The document I've pointed to (RA60) says "The 35 MHz is 
dedicated solely to aeronautical modelling."  I couldn't find IR2030 
document on the Ofcom site.

I am also curious because my son is tempting me to buy a helicopter.  The 
last time I asked in the model shop the bands were 40 MHz for surface, 35 
for air and 27 for any model.

   Vadim

Paul Keinanen <keinanen@sci.fi> wrote in message news:<22qle0pigmugemh0giacdeiruv2glc1g0h@4ax.com>...
> On 6 Jul 2004 09:31:24 -0700, me@linnix.info-for.us (Linnix) wrote:
> 
> >You can't put someone in jail just for thinking of trying something.
> 
> Like drinking a bottle of whisky and then driving around in a car
> without brakes :-).

That's fine if he is driving in his own land without anybody around.

> 
> >He might own the entire 400 meters air and ground space.  
> 
> Depending of the sped of the model aircraft, it does not require a
> long communication failure to fly outside even this area. 10-40 s
> should be enough.

A well designed system should have emergency homing system and/or GPS.

> 
> The situation for a model helicopter may be different _if_ the
> helicopter goes into a autoratoation mode upon loss of command link
> and lands more or less intact close to the point of communication link
> failure.

What if he is testing communication link/control in high interfence
situations?

>  
> >Even if he
> >carry out the experiment and did some damages, he should be responsible
> >financially.  
> 
> What is the price of a dead person ?

Depends on how that person got into the test area.

> 
> >If he did not intend to cost such damage, he should not
> >be in jail.
> 
> I think "criminal negligence" is term used in the US.

Depends on the circumstances.  Appearancely, you already found him
guilty and handled down your sentense without any considerations.

> 
> My point is, why use a risky method, when there are other methods
> considered to be more safe (frequencies allocated for model aircraft
> control) ?

Risk assessment is very subjective.  Tell the Wright Brothers not to
fly when driving is just as good.

>  
> Paul