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What is this camera like thing on electronic shop price tags? (And how does it work) (lemmy.zip)
submitted 2 years ago by to c/technology@beehaw.org
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I first thought it was a camera but there was no point, After some searching I found that these things could communicate optical,, so that might be it, if so how do they work?

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[–] 11 points 2 years ago (1 child)

Yup. They use ceiling-mounted IR transmitters that are a bit like a big multi-directional TV remote control.

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  • [–] 9 points 2 years ago (3 children)

    I'm pretty certain these ones use visible light, with ceiling-mounted LEDs. They flash at specific frequencies that are imperceptible to the human eye, but can be interpreted by the electronic shelf label. Here's a whitepaper explaining the concept.

    Source: for 20 or so years, I worked in technology for some of Australia's largest retailers, and we tested a lot of these sorts of things in our labs. Very cool stuff.

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  • [–] 2 points 2 years ago

    Hmm. They're very common in NZ now, however it appears that document is talking about modulating the actual normal shop lighting, not just an independent transmitter.

    I redid the electrical in a supermarket already fitted out with Pricer gear, and we went from dumb electronic-ballasted fluoros to dumb-driver LEDs, no DALI and certainly no comms uplink or modulation smart enough for that. I'm aware that the document suggests power-line communication to the drivers, but these were off the shelf dumb drivers/ballasts.

    The ceiling mounted Pricer transceivers would have been doing all the transmitting, and as I never saw any visible light coming out of them, and the HF ripple and instability from the shop lighting would have been significant, I think it's pretty safe to say they were using some form of IR.

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