"some" more ideas with sound and LF/VLF Re: Idea: datatransmission using ultrasound

Robert Michel openmoko at robertmichel.de
Fri Dec 15 19:03:06 CET 2006

Salve Ole!

On Fri, 15 Dec 2006, Ole Tange wrote:

> Apparently the Neo may be capable of transmitting ultrasound (20 KHz -
> around 45 KHz). If the Neo is also capable of receiving this (using
> the microphone) then we should be able to transmit data that way. This
> may be useful for close range network (e.g. transmit business card).

> The protocol will be similar to wireless ethernet. The range will be
> similar to Bluetooth.
"b word"?
*jehova* *jehova*

I would compare it with IrDA - (BTW AFAIremember, the first TV remote 
controlles have be with ultrasound) audio is directed and surpressed
by things inbetween - so it doesn't work while the Neo is in your
I would love to play with the ultrasound potentiality and realy
hope that the mic and the speakers would support so high frequencies
- but don't let us forget that hearable sound would be a chance
to communicate with existing hardware - but I have doubts that for
a business card someone would install a J2ME applet on a non Neo
to "beam" or "recieve" this - but it would be a chance for
owner of a mobil without IrDA/Bluetooth.
Audio+J2ME does have much more phones :)))

How expensive is a simple speaker and a simple mic?
When they are on the opposide of the screen, you could put your
Neo on a phone with cheap/free calls and use this cheap connections..
acustic coupler

Back to ultrasound - then for biologist a "Microbat Detector" would
be possible :)

To see on freshmeat programs for Ham Radio is inspiring:

Yesterday night I saw there Baudline:

   Baudline is a time-frequency browser
   designed for scientific visualization of the spectral domain.  Signal
   analysis is performed by Fourier, correlation, and raster transforms
   that create colorful spectrograms with vibrant detail.  Conduct test
   and measurement experiments with the built in function generator, or
   play back audio files with a multitude of effects and filters.  The
   baudline signal analyzer combines fast digital signal processing,
   versatile high speed displays, and continuous capture tools for
   hunting down and studying elusive signal characteristics.
   Explore, Analyze, and Discover.
It has to ported to arm - but mustery-signal are inspiring
what "noise" could be detected and maybe used as event:
Detecting running TV...
That could influence your profile for incomming Calls/SMS/Emails/Chat...
when you are at home, the time is ... and you do.... you are not directly
reachable for ....

It is not only usefull for deaf people, you could learn your
Neo that special sounds will be an event/an alarm - glas breaking,
door opening... while you sleep or put one Neo close to a maschine
and learn "normal sound" and get an alarm when the prozess get
louder - get a different sound pattern or when it stopps 
(Use like that would create a use for have two Neos *g*)

The other audio tool is 

I already wrote about a magnetic loop into the sound input
for lightning detection:
A simple magnetic loop (inside of the neo, switchable to it)
would not only detec lightning  or japanese time radio,
it could also used for more..
A normal electrical switch for your light could be a patter
for your "sound" analysing. 
Localisation info (AGPS) of your Neo helps that this analysing
is only on, were you want it (and the pattern db could be a
local one) - and the time could controll that it is on only when
you want it.

So the normal lightswitch in your bathroom could be used to start
something - e.g. playing the wether and morning news.
Switching on your floor lamp at the afternoon could switch on
your music - switching  off and on could change the music gengre...
It mustn't be your Neo playing something - it could send this
information to another device.

Sound analysing could help to detect maschines disfunktkion
- record the sound pattern of a maschine when it is new,
and than check it from time to time and see if something changed.

The phone could be a good dB meter - to encrease the accuracy,
somebody could sell Neo1973 with a detailed fingerprint of
mic and speaker.

So when the neigbour, your hotel, the music in the pub is too loud,
you could complain it on a professional way - it is now
12 dBm to loud - comparing to the norm iso123...

Stero mic instead of mono mic
Imagine your phone is in the middle of the car and you are
left from it, a stero mic could be used that the right mic
channel is muted and software could try that the noise
from the right side will be used for noise reduction on the
left channel.

Stereo mic could be used for positioning without GPS.
When you can see 3 markant peaks (mountain, tower...)
put down a map with thise peaks on your neo. mark
this peak points and where you think you are, or just
the order that you can see them.
Put down your so that you can go some stepps back (2-10m) 
and bearing of a direction by having the neo in the line 
between the peak and you.

The neo will ask "peak 1 - mountain Broken" and you will
bearing of that direction and clap your hands.... and so
on - with calculation the stero sound signal it is possible
to calculate from which direction this clapping came.
(Two possibilies - but based on the map and the order
it should be clear)
An electronical compass could help - but is not neseccery.

So I hope that the Neo1973 will have:
- an audio in (stereo, with 3mA Bias)
- ultrasound power
- good mic / speaker solution for a good hand-free speaking
- make the 3 DAC externaly usable - DJ with stereo to the
  PA, mono Prelistening for this headphone
- build in stereo mic


Some more ideas about sound, not fully worked out:

--Sound analysing
-- (simple) db-A meter
--- with alarm level as event for other programs
--- e.g. call the police automaticaly with voice message
    when noice from disco/pub in the neighour house over the limit for
    more then 10 minutes
-- babyphone
-- squelch
--- speak to speak (instead of push to speak)
--- clapp to speak
--- look ahead for some seconds (e.g. 2) with an loop so that
    recording or transmission/broadcasting is starting 2 seconds
    before sound/speach was louder then the choosen level
-- silent warning/event - when noise lower than a limit for a period
   start a program (e.g. MP3 player connected to an open mixer channel)
   or call a person
-- glassbroken / hits -detector
   --abnormal noise trainer
--- material test (broken, not broken)
--- material test which material is it (e.g. kind of metall based on sound)
--- schallbrücke (when a house has a construction mistake and sound is
    not isolated enough...)
-- sound event counter (cars, trains...)
-- frequenzanalysing (white noise)
--- room analysing - echo... 
--- voice commands
-- voice recongnition

- string tuner
-- give 440Hz
-- test 440Hz
- metronom
- drummachine
- sampler - record sound and manipulate it
- combinine 2 or more Neo1973 to have a multi channel mixer/recorder
  (using GPS time signal for high accurate syncronisation :)
--sound to midi - ping/skirl with your mouth or play an instrument
   and get the midi notes from that
- Midiplayer
- frontend to use 1-2 USB-CD player  audio out with digital mixing
  with the Neo1973
--- singing quality check for solo singer and chorus
-- guitare sound effecet - plug your Neo1973 between your Guitar/ebass 
   and your amp (ohh they are normaly used as pedal - so the Neo
   must be stable or USB pedal is used....
   ha! use sound commands for switching the digital guitar effects
   shout "total overdrive", "Nirvana" "U2" to your neo. "more" or "less"
-- Jammtogether
   multiplayer network via GPRS/datacall/BT and midi
   - maybe delay your sound so that it is timed your partners
     (messuring of the delay from the users and delay the reaktion
     of your sound - to give a keyboard feedback maybe start with
     lower sound or only on one channel
   - multi midi-channel recording of your jamming for postproduction

more audio/linux inspirations maybe from the Linux audio distribution

-> agnula starting an official research program with some institutes
and getting government aid (EU) for this research

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