[LINK] Nokia lightning detector patent application

Sat May 26 00:36:04 AEST 2007

I was looking at a quick install guide for a cordless skype phone the  
other day here:
http://www.linksys.com/servlet/Satellite? 
c=L_Product_C2&childpagename=US% 
2FLayout&cid=1165633354987&pagename=Linksys%2FCommon%2FVisitorWrapper
Under the link that says: Quick Install, it's a pdf and in it has a  
list of things not to do with the "cordless" phone:

Avoid using a telephone during an
electrical storm. There may be a remote
risk of electric shock from lightning.

A generic list?  I can't see how you can possibly get an electric  
shock through a cordless phone.  Maybe a loud noise in your ear but  
it's digital so that doesn't seem likely either.

Kim

On 2007/May/25, at 1:55 PM, stephen at melbpc.org.au wrote:

> There's a new Nokia (US) Patent Office application for:
>
> "A lightning detector and a lightning detection method.."
>
> <http://appft1.uspto.gov/netacgi/nph-Parser?
> Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=%2Fnetahtml%2FPTO%
> 2Fsrchnum.html&r=1&f=G&l=50&s1=%2220070085525%
> 22.PGNR.&OS=DN/20070085525&RS=DN/20070085525>
>
> BACKGROUND OF THE INVENTION
>
> [0002] Thunderstorms are a major weather hazard, but are difficult to
> predict. They can travel at speeds of 20 km/h to 40 km/h, and  
> lightning
> strokes may occur more than 10 km in front of the rain clouds and  
> equally
> some distance behind the rain clouds. While a lightning stroke is
> produced by a cloud or a weather front, many of the most dangerous
> lightning strokes actually occur when no visible clouds are present  
> above
> as a warning of a thunderstorm. Thus, a system that warns of  
> possibility
> harmful thunderstorms, even if only approximately proximately ten  
> minutes
> before they become visible, can be considered a major safety feature.
>
> [0003] There is a large population that would benefit from such a  
> safety
> feature. To some persons, it might provide only a nice-to-know  
> everyday
> knowledge. To a considerable number of persons, however, storm and
> lightning originated threats have significant implications in the  
> form of
> an increased risk, loss of property or even fatal consequences. A
> lightning alerting system is of particular interest, for instance, for
> persons spending much time outdoors, and equally for aviators,  
> navigators
> or the like. A system providing a warning of lightning even when the
> weather seems to be perfectly calm and clear may enable a person to  
> take
> suitable safety measures in time, for instance seek shelter etc.
>
> [0004] From the state of the art, many single-purpose lightning  
> detectors
> are known, but they have some disadvantages from a commercial
> perspective. Scientific lightning detectors, which are used in
> meteorology, are very large and their range is hundreds of kilometers.
>
> [0005] Also other high-end lightning detectors using a single radio
> frequency (RF) band are large and relatively expensive, compared for
> instance to mobile phones. Moreover, they are usually required to  
> have a
> specific orientation, for instance standing on a wall or on a desk  
> stand,
> in order to gain the required accuracy or directionality. They are  
> thus
> not well suited for a truly mobile use. These devices typically have
> further to be positioned in a certain way and held stationary for  
> several
> minutes before a reliable detection of a thunderstorm becomes  
> possible.
>
> [0006] In addition, there are now existing rather inexpensive low end
> lightning detectors which are completely portable in size and which do
> not require a specific orientation. These detectors, however, are
> extremely susceptible to man-made electromagnetic compatibility (EMC)
> emissions and thus tend to cause spurious alarms especially in an  
> urban
> setting or near highways
>
> [0007] Currently most of commercially available mobile lightning
> detectors detect lightning strokes by measuring the electromagnetic
> emission caused by lightning at very low frequencies (VLF: 3-30  
> kHz). In
> addition, it has been known for decades that lightning strokes can
> be "heard" by using a traditional AM broadcast radio receiver, which
> operates at longwave frequencies (150 to 300 kHz), mediumwave  
> frequencies
> (500 to 1700 kHz) and shortwave frequencies (SW: 2 to 30 MHz).  
> However,
> numerous publications exist where lightning have been detected and
> measured by its emission at HF and VHF frequencies between 3-300  
> MHz and
> even at higher (UHF) frequencies.
>
> SUMMARY OF THE INVENTION
>
> [0008] The present invention proceeds from the consideration, that a
> lightning stroke is a single flash which produces besides a visual  
> signal
> and a partly audible pressure signal as well a brief but strong
> electromagnetic pulse extending over a wide variety of wavelengths.
> Typical electromagnetic pulses caused by a lightning stroke cover the
> frequencies between 10 Hz and 5 GHz with a peak around 500 Hz, i.e. in
> the audio frequency range. At a normalized distance of 10 km, the
> amplitudes of such pulses range from 107 mV/m to 1 mV/m in a  
> bandwidth of
> 1 kHz. the strongest signal of the electromagnetic pulse is the  
> induced
> electric field caused by the vertical current in the lightning stroke,
> and this is the parameter that is most commonly measured in large- 
> scale
> distance-bearing devices.
>
> [0009] However, due to the complexity of the lightning stroke  
> phenomenon,
> there are also strong signals in the extremely low frequency (ELF)  
> range
> of a few hundred Hz or less, and weaker signals extending up to the  
> GHz
> range and above.
>
> [0010] It is a well-known fact that the exact characteristics and time
> spectra of the electromagnetic interference (EMI) signatures are
> different in the MHz range that in the kHz and Hz ranges due to the
> slightly different meteorological mechanisms causing them.
>
> [0011] For the purposes of the present invention it is sufficient  
> to note
> that at all frequencies of interest, a lightning stroke is  
> accompanied by
> an EMI pulse that can be identified at a distance of many kilometers.
>
> [0012] As a result of the lightning stroke generated EMI pulse, RF
> channels are briefly interfered during a lightning stroke in the
> vicinity. The impairment of RF receivers due to an EMI caused by a
> lightning stroke can be experienced in using an AM/FM radio, TV or  
> over
> power supply lines in form of statics, clicks, scratches, noise or  
> loss
> of sound or picture. Disturbances in RF channels due to a lightning
> stroke can be sensed at very large distances. Specialized and large- 
> scale
> lightning detectors are able to detect lightning disturbances, so- 
> called
> sferics, at a distance of several hundreds of kilometres from a  
> lightning
> stroke, although these detectors typically operate by measuring the
> induced electric or magnetic field rather than the interferences in an
> audio or RF signal as the present invention.
>
> [0013] Ordinary AM radios are known to suffer from EMI disturbances  
> at a
> distance up to 30 km or more from a lightning stroke, which can  
> even be
> heard directly in an audio signal as various clicks. At higher
> frequencies than the AM bands the signal is typically much weaker  
> due to
> both atmospheric attenuation and different causation mechanisms,  
> but is
> nevertheless detectable at large distances.
>
> [0014] While in known mobile RF devices, such as ordinary mobile  
> phones,
> electromagnetic interference in received RF signals are eliminated
> immediately by filtering, it is proposed in the present invention that
> such electro-magnetic interferences in a monitored RF channel are
> evaluated. If a detected interference seems to be caused by a  
> lightning
> stroke, a user of for example a mobile phone can be alerted. An
> interference can be assumed to be caused by a lightning stroke, for
> example, if it exceeds a predetermined threshold value or if it has a
> frequency spectrum which is characteristic of a lightning stroke. The
> lightning detection can be on as long as the RF detection is on.
>
> [0015] The present invention thus provides a new security feature that
> can be implemented in a mobile RF device, for example a cellular  
> phone.
>
> [0016] While in many case, the desire to detect lightning strokes  
> in the
> vicinity may not be large enough to justify the costs and the  
> difficulty
> of carrying along a dedicated lightning detector, many people would
> appreciate a low-cost sensing system that could be integrated with a
> device that they are already carrying along in any case, especially  
> like
> a mobile phone. The known art does not provide for such an  
> integration of
> a lightning detection as a new functionality in known mobile RF  
> devices.
>
> [0018] The present invention is based on the idea that the incoming
> spectrum generated by a thunderstorm is studied using all or many
> available RF channels available in a mobile RF device, such as a  
> cellular
> phone. Because of the many radio interfaces (i.e. hundreds of  
> channels in
> each of the three bands in a tri-band receiver, the Bluetooth receiver
> frequencies, the FM radio including the pilot tone channel, the Wi-Fi
> radio local area receiver, the RFID tag reader and even the RDS and/or
> DARC receivers) the present invention provides a new and feasible  
> method
> for lightning detection.
>
> [0019] Thus according to the first aspect of the invention, the  
> present
> invention is based on the use of at least two channels, at least  
> one of
> which is a telecom channel, for lightning detection.
>
>
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>
>
>
> _______________________________________________
> Link mailing list
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--
Kim Holburn
IT Network & Security Consultant
Ph: +39 06 855 4294  M: +39 3494957443
mailto:kim at holburn.net  aim://kimholburn
skype://kholburn - PGP Public Key on request

Democracy imposed from without is the severest form of tyranny.
                           -- Lloyd Biggle, Jr. Analog, Apr 1961