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?
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?
Yup. They use ceiling-mounted IR transmitters that are a bit like a big multi-directional TV remote control.
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.
They’re IR. Source: I have 5 Pricer labels sitting on the counter next to me.
Ah, fair enough. It’s been a long time since I clapped eyes on the test ones we had.
The light is visible, the flashing isn’t.
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.