[HN Gopher] Kiwink: Visible Light Communication via phone camera...
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Kiwink: Visible Light Communication via phone camera/flash
Author : walterbell
Score : 47 points
Date : 2022-03-19 15:56 UTC (7 hours ago)
(HTM) web link (kiwink.io)
(TXT) w3m dump (kiwink.io)
| smangold wrote:
| This is a copy of earlier work done (for example) at Walt Disney
| Research. Contrary to scientific work, startups do not usually
| cite related work.
|
| https://studios.disneyresearch.com/2012/12/03/an-led-to-led-...
|
| https://la.disneyresearch.com/publication/connecting-network...
| lousyd wrote:
| Low bandwidth could be a feature. You'd know that your winking
| product can't be sending a whole lot of information about you
| that way. Or at least it would take a while to do so.
| londons_explore wrote:
| It only takes a fraction of a second to send a 40 bit
| identifier, and that's enough to identify any human on the
| planet.
| jaflo wrote:
| Reminds me of the Bloomberg B-Unit authentication
| (https://www.bloomberg.com/professional/support/b-unit/, step 5)
| where it shows as flashing light to enroll a token generator for
| their terminal.
| a-dub wrote:
| or the timex datalink watch that downloaded from the computer
| via bitbanging monitor flashes.
| https://en.wikipedia.org/wiki/Timex_Datalink
| myself248 wrote:
| That was my first thought.
|
| When I got my first Indiglo watch, I realized the backlight
| had such fast rise/fall times (as compared to its
| incandescent predecessors) that it could be used to transmit
| data. I imagined watches with photocells, held face-to-face,
| flickering their backlights at each other to "synchronize
| watches" before a special-ops mission or something.
|
| A few years later, Timex DataLink came out, indeed using a
| photocell to receive data, but not using the backlight to
| transmit it! And in all the years since, nobody ever took
| advantage of that.
|
| But here we seem to be, with phones, a million times more
| powerful and a million times less power-efficient.
| Inityx wrote:
| https://www.youtube.com/watch?v=GCHHzw4s5W4
| neilv wrote:
| Seems related to IrDA, only using current hardware on consumer
| end (though phones might've had IrDA in the past):
| https://en.wikipedia.org/wiki/Infrared_Data_Association#Rece...
|
| > _IrDA was popular on PDAs, laptops and some desktops from the
| late 1990s through the early 2000s. However, it has been
| displaced by other wireless technologies such as Wi-Fi and
| Bluetooth, favored because they don 't need a direct line of
| sight and can therefore support hardware like mice and keyboards.
| It is still used in some environments where interference makes
| radio-based wireless technologies unusable._
|
| > _An attempt was made to revive IrDA around 2005[3] with
| IrSimple protocols by providing sub-1-second transfers of
| pictures between cell phones, printers, and display devices. IrDA
| hardware was still less expensive and didn 't share the same
| security problems encountered with wireless technologies such as
| Bluetooth. For example, some Pentax DSLRs (K-x, K-r) incorporated
| IrSimple for image transfer and gaming.[4]_
| pacaro wrote:
| Irda was most definitely available on phones. It was possible
| to get a laptop online by correctly aligning it and a phone on
| a desktop. Also very commonly used by printers
| Avery3R wrote:
| This website does something weird with scrolling and is
| impossible to use
| joering2 wrote:
| Same here on desktop Chrome. I think its a poor execution of
| Tesla site. Moment I touch the wheel it takes me to next
| slide... that is - split on the screen with the previous one.
| Nightmare.
| moonbug wrote:
| irda patents must've expired.
| nerdponx wrote:
| > Get access to extensive user-experience data
|
| Yikes.
| ceroxylon wrote:
| > The light cannot be hacked
|
| Double yikes.
| nonsapreiche wrote:
| > Does not emit radiation
|
| triple!
| contravariant wrote:
| Wait how does that work? Emitting radiation is literally
| the only job a light has.
| seanw444 wrote:
| Not sure what you're talking about. Isn't radiation that
| green cloud of poison like in Hollywood? It's scary
| stuff, man!
| krisoft wrote:
| It is deeply wild that the "hello world" project of
| arduino like systems is to on-off modulate a ~500 THz
| electromagnetic wave emiter. (Aka blinking an led)
|
| Also that if you want to emit in the mhz range you need
| permissions and specialist equipment, but in the ~500 THz
| range you can just use a sub-dolar part and go ham with
| it without needing to be a ham.
| [deleted]
| jwsteigerwalt wrote:
| Seems like a patent troll trying to put their mark on obvious
| technology.
| a-dub wrote:
| or a design firm that accidentally reinvented the remote
| control.
|
| if they built a protocol around it that handles error
| correction and noisy/intermittent links as well as nice apis
| for both sides, then i'd say they have something interesting.
| nonrandomstring wrote:
| An audio version of this sort of thing was Chirp. I wrote the
| original audio code to implement something that sounded
| aesthetically pleasing like a bird twitter, but actually used
| multi-carrier FM plus error correction and a whole bunch of stuff
| to be a "constellation" modem. I believe the company are still
| going. IIRC, when I left they'd got to the point of realising
| that in a noisy environment, even with echo cancellation, you
| couldn't really do serious data transfer - and why would you if
| you have Bluetooth anyway.
|
| The real application for these "last meter" contactless ideas
| that use stalwart built-in transducers like mic+speaker or
| LED+camera, are to send short codes, such as shortened URLs.
| There's a whole bunch of fun to had using them for surreptitious
| advertising and public steganography.
| melony wrote:
| 1.5 kb/s at 5 cm is rather bad. Assuming 24fps (typical
| smartphone camera) sample rate with QAM-256 modulation, shouldn't
| the bandwidth be at least a magnitude higher even after error
| correction? They have 16 LEDs, assuming half are fiducial
| markers, they will have 8 extra channels.
| londons_explore wrote:
| With the rolling shutter of smartphones, combined with the fact
| the light from the led will spread slightly throughout the
| frame (dirt in the lens etc), you effectively get one piece of
| information per _row_ of the image. So a 1080p60 video, which
| most phones are capable of, gives you 64kbps.
|
| With no feedback channel though, one can't characterize the
| channel though, so you need to have super large margins to be
| sure it's going to work.
| kortex wrote:
| How do you do quadrature modulation of light? There's no phase
| information? Or do you just mean 8-bits-per-symbol encoding?
|
| Or does the amplitude of the led vary continuously? I was
| assuming PCM.
| charcircuit wrote:
| Where are you seeing 16 LEDs? Everything on the site seems to
| suggest it's a single LED. I'm not sure how you reach 1.5kbps
| with a single LED on a wide range of phones.
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(page generated 2022-03-19 23:01 UTC)