_______ __ _______
| | |.---.-..----.| |--..-----..----. | | |.-----..--.--.--..-----.
| || _ || __|| < | -__|| _| | || -__|| | | ||__ --|
|___|___||___._||____||__|__||_____||__| |__|____||_____||________||_____|
on Gopher (inofficial)
URI Visit Hacker News on the Web
COMMENT PAGE FOR:
URI Transmitting data via ultrasound without any special equipment
kragen wrote 7 min ago:
No special equipmentâexcept a laptop capable of running a web browser
that can do Web Audio, and microphones and speakers. Which, as the
article explains, isn't novel. But it's still a nice introduction to
the space.
I would argue that microphones and speakers are special equipment: most
microcontrollers don't have them, most computers are microcontrollers,
and most non-microcontroller computers already have better ways to
transmit data. I was hoping for an ultrasound codec for an Arduino
using the microphonics of the X5R bypass capacitors included on the
board, or something like that. Plausibly that is a thing you could do,
but nobody has managed it so far that I know of.
vishnuharidas wrote 2 hours 26 min ago:
Reminded me of LG Smart Diagnosis. Almost every LG appliances come with
an audio-based diagnosis system. Look for "LG Smart Diagnosis" on
YouTube and you will find hundreds of videos of LG washing machines,
AC, Fridges, and other devices using a music-like audio for diagnosis.
velcrovan wrote 3 hours 17 min ago:
So thatâs how Bobby Tables got his start
amelius wrote 3 hours 33 min ago:
Speaking for all the dogs and other pets with hearing abilities above
20kHz ... please don't do this.
polotics wrote 5 hours 30 min ago:
what is it about websites that can't be zoomed? do the authors not
realise their choice of fonts won't always fit with mobile phone
screens?
nine_k wrote 4 hours 41 min ago:
IIRC mobile Firefox ignores the "can't be zoomed" setting, which I
find the right thing to do.
lxe wrote 5 hours 55 min ago:
18-20khz is not really ultrasound. Many people can still hear this
range, and it's very unpleasant when played (at least to me).
For comparison, medical imaging ultrasound is 2-20 MHz (that's MEGA
hertz) I think,
dylan604 wrote 4 hours 51 min ago:
would the stock equipment be able to produce MHz? consumer gear is
targeted specifically at making sounds humans can hear. Since the
18-20kHz is within the 44.1-48kHz audio tends to playback, it makes
since why it would be near-ultrasound frequencies. The headline
specifically mentions without any special equipment
lxe wrote 4 hours 14 min ago:
Theoretically, yes! With 192kbps sample rantes you can probably
render up to 96khz, but the limitation is the speaker and amp
components all the way from your DAC to the main amp to the
speaker.
dylan604 wrote 4 hours 3 min ago:
bitrate isn't really what we're concerned with here, though is
it? if you use 96kHz sampling rate, you can reproduce 48kHz
frequencies according to Nyquist. the bitrate would then be the
sampling rate * bit depth * #channels. your 192kbps would
potentially be the 96kHz * 2 channels, but you've left out the
bit depth or using a 1-bit sample???
thfuran wrote 5 hours 44 min ago:
Yeah, 18 kHz isn't really ultrasound, but 50 kHz definitely is and
nobody's hearing that. You definitely don't need to go up into the
MHz range and can't if the goal is to use existing audio equipment.
lxe wrote 4 hours 17 min ago:
They are using the 18-20Khz range though ( [1] )
URI [1]: https://halcy.de/blog/images/2025_06_27_fsk.png
TrackerFF wrote 6 hours 4 min ago:
IIRC, there was some commercial product - years ago - that worked by
using ultrasonic data transfer.
It went something like this: You install some app on your phone, which
then listens for incoming audio in the ultrasonic range. The audio is
coded instructions, which then would do things like blink a light on
your phone or whatever. The idea was that this could be used at events
(sport, music, whatever) to create light shows on the mobiles, without
relying on good wifi coverage or similar in the avenue. As you could
use the PA for the data transmission.
mgraczyk wrote 4 hours 12 min ago:
Google explored doing this with devices that connect to each other,
specifically Chromecast and their early Google Home devices. I don't
think it ever launched but Google did some interesting experiments to
test the ultrasonic transfer functions on millions of consumer
devices. (I worked in audio research at Google at the time but not on
this).
I believe the main problem is that it makes dogs go crazy
tanepiper wrote 5 hours 24 min ago:
I wrote a very similar web implementation 12 years ago as a proof of
concept - if it got the go-ahead, the plan was to test it with some
commercial TV broadcasting in the UK where a ultrasonic short code
could be sent to phones using an app with a Web view, or possibly
native app.
Sadly never got picked up, although we proved the concept could work
- but it certainly had it's challenges. [1]
URI [1]: https://github.com/tanepiper/adOn-soundlib
URI [2]: https://github.com/tanepiper/adon-ad-platform
avsm wrote 5 hours 40 min ago:
We demonstrated this in 2003 using the smartphones of the era (they
didnât have good filters, so you could detect ultrasound quite
easily).
See [1] sec 2.1 for the 2003 paper and some ancient videos at [2] if
you want some Nokia nostalgia :-)
URI [1]: https://anil.recoil.org/papers/audio-networking.pdf
URI [2]: https://anil.recoil.org/projects/ubiqinteraction
jnwatson wrote 6 hours 41 min ago:
Chromecast has used ultrasound in lieu of pairing code for a while now.
jayknight wrote 4 hours 37 min ago:
Webex on a laptop can know which conference room it is in by
ultrasound, which allows quick screen sharing to the screen/meeting.
echoangle wrote 6 hours 53 min ago:
Isn't the "Illustrated for zoomers" version of the frequency domain
wrong? I'm pretty sure the bars over the timeline show volume over
time, not intensity over frequency. So the middle bar doesn't represent
a specific frequency but a specific time interval in the song.
thijson wrote 7 hours 3 min ago:
It might be useful to study the techniques that modems used to transmit
data over phone lines. I seem to recall trellis coded modulation being
used: [1] The acoustic channel is bound to suffer from multipath too,
so some equalization may be needed too. [2] [3] In order to receive the
signal far from the transmitter, some form of spread spectrum encoding
could be used, like CDMA. The spreading factor could be negotiated.
URI [1]: https://en.wikipedia.org/wiki/Trellis_coded_modulation
URI [2]: https://en.wikipedia.org/wiki/Equalization_(communications)
URI [3]: https://www.ti.com/lit/an/spra140/spra140.pdf
URI [4]: https://en.wikipedia.org/wiki/Direct-sequence_spread_spectrum
ghurtado wrote 6 hours 55 min ago:
Did somebody say Spectrum? [1] I always assumed that PWM was the
go-to method for this kind of low bandwidth / high noise medium, I
wonder why the author didn't go that route and used FM instead
URI [1]: https://softspectrum48.weebly.com/notes/tape-loading-routine...
nomel wrote 5 hours 57 min ago:
> Tape data is encoded as two 855 T-state pulses for binary zero,
and two 1,710 T-state pulses for binary one.
Is that not FM, more specifically FSK, just with some extra
harmonics?
ghurtado wrote 4 hours 36 min ago:
keep in mind I don't know much about waves, so all of this could
be wrong, but I think PWM works by modulating the width of the
pulse, in other words, the "duration of the note" if you will, so
the frequency of the square wave remains constant. You have a
high pulse of width t to represent a zero and a high pulse of t*2
to represent 1. The human ear might hear this as a modulating
frequency, but that's only because the pulses are changing faster
than our brains can recognize pitch, if that makes any sense . I
don't know what a t state is, but I suspect the number is the
duration of the pulse in microseconds or something of the sort.
I believe IR remotes work on a similar principle: a series of
blinks of two different durations, which represent 0 and 1
cogman10 wrote 7 hours 0 min ago:
Another step to look into if you really want to have fun is
implementing some sort of QAM.
ac29 wrote 7 hours 27 min ago:
See also:
URI [1]: https://github.com/ggerganov/ggwave
blensor wrote 6 hours 9 min ago:
GGWave is a really great tool and does support audible and inaudible
versions.
We are using it in XRWorkout to automatically sync up ingame
recordings with external recordings, we are using the audible version
instead of the ultrasound version so a human can sync it up too if
they are using a regular video editor instead of doing it
automatically in our own tools
Here is an example how that sounds
URI [1]: https://xrworkout.nyc3.digitaloceanspaces.com/data/video/036...
noman-land wrote 3 hours 19 min ago:
This seems like such a fun way to work out but not with a VR helmet
on.
adzm wrote 7 hours 41 min ago:
The web tool is fun! I decided to give it a harder test and turned up
some fans and background music up pretty loud and it still managed to
decode the message.
Though after a certain point it stops recognizing it, I was still
surprised how well it did with noise. I'm sure noise in higher
frequencies (or the right harmonics) would be much harder to handle,
but solvable in interesting ways too
DIR <- back to front page