this post was submitted on 09 Dec 2023
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Technology

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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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[–] [email protected] 13 points 11 months ago* (last edited 11 months ago) (1 children)

The top white rectangle is a multi-color LED (presumably RGB). Can't make out what's in the bottom, but I wouldn't be surprised if it was some form of light sensor for (literally) flashing new information onto the tag.

[–] [email protected] 11 points 11 months ago (1 children)

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

[–] [email protected] 9 points 11 months 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.

[–] [email protected] 4 points 11 months ago (1 children)

They're IR. Source: I have 5 Pricer labels sitting on the counter next to me.

[–] [email protected] 1 points 11 months ago

Ah, fair enough. It's been a long time since I clapped eyes on the test ones we had.

[–] [email protected] 2 points 11 months 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.