Kiwink: Visible Light Communication via phone camera/flash

by walterbell • 4 years ago

60 32 4 years ago

jaflo• 4 years ago

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-dub2• 4 years ago

or the timex datalink watch that downloaded from the computer via bitbanging monitor flashes. https://en.wikipedia.org/wiki/Timex_Datalink

myself248• 4 years ago

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• 4 years ago

https://www.youtube.com/watch?v=GCHHzw4s5W4

nerdponx2• 4 years ago

Get access to extensive user-experience data

Yikes.

ceroxylon• 4 years ago

The light cannot be hacked

Double yikes.

nonsapreiche• 4 years ago

Does not emit radiation

triple!

jwsteigerwalt• 4 years ago

Seems like a patent troll trying to put their mark on obvious technology.

a-dub2• 4 years ago

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.

melony• 4 years ago

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.

kortex• 4 years ago

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• 4 years ago

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.

londons_explore2• 4 years ago

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.

neilv• 4 years ago

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• 4 years ago

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

emteycz• 4 years ago

IrDA was widely used to share music among children (~2005). Lasted just a few years though, phones started having bluetooth around 2007.

causality02• 4 years ago

Man I miss having a handheld with IrDA on it. I had every device in my house programmed into my Palm. TV, VCR, air conditioner, DVD player, stereo. Not to mention all the universal remote apps that'd let you change the channel and volume in bars, restaurants, and waiting rooms.

Stevvo• 4 years ago

Some brands still put IR blasters on every handset e.g. Xiaomi/POCO.

Avery3R• 4 years ago

This website does something weird with scrolling and is impossible to use

joering2• 4 years ago

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• 4 years ago

irda patents must've expired.

lousyd• 4 years ago

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_explore2• 4 years ago

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.

smangold• 4 years ago

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...

nonrandomstring• 4 years ago

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.

jeroenhd• 4 years ago

This can probably be sabotaged quite easily by putting a powerful enough near-visible light LED somewhere else in the room and a high-res camera to record responses. Many phones have trouble filtering out some IR (you can test this by aiming a remote at your phone with the camera app open, mine shows IR as pink light) and I don't expect communication lights to be too bright because of the discomfort that comes with flashing.

I also think this tech is entirely impractical for one single reason: flashing visible lights can easily induce seizures.

With BLE available in pretty much every OS (and even in many browsers), I don't see the added value of quickly flashing a smartphone flash light.

loewerj• 4 years ago

some older references or even implementations:

https://www.youtube.com/watch?v=O3Pf4TZ_vOE

https://github.com/gioblu/PJON/tree/master/src/strategies/An...

http://mecrisp.sourceforge.net/ledcomm.htm

https://hackaday.com/2019/12/22/optical-communication-using-...

Kiwink: Visible Light Communication via phone camera/flash

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