Using the Lighthouse deck for visible light communication (VLC)

Topics related to the Lighthouse positioning system, configuration and use
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rampudia
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Joined: Fri Mar 26, 2021 4:21 pm

Using the Lighthouse deck for visible light communication (VLC)

Post by rampudia »

Hi!

I want to use the Lighthouse deck to take advantage of the photodiodes (PDs) onthe board to do visible light positioning without the need of creating a new custom board. I see that the PDs have a good enough sensitivity response in the visible light spectrum and I want to log the received signal strength (RSS) of the four BPW34S. Would that be possible with the current board configuration? Is it possible to extract such information from the TS4231 by software directly? Would I need to re-program the FPGA?

I am a bit lost about the functioning principle of the HTC Vive stations, so any pointers on how to adapt the lighthouse deck to measure the light intensity received by the PDs would be appreciated.
arnaud
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Re: Using the Lighthouse deck for visible light communication (VLC)

Post by arnaud »

I do not thing you can extract signal strength from the TS4231. Once the TS4231 is setup, it acts as a signal detector and gives us only two 1bit information: envelope and data (ie. data is outputting the carrier). As far as a know it is designed for this use-case only.

The FPGA is currently programmed to output pulse timestamp, width and the first 17bit of decoded data for each pulse. In case of Lighthouse V2 the carrier is a 6Mbit/s BCM-modulated datastream, this is what the fpga decodes. If you transmit these kind of pulse, you can re-use the deck do decode your pulses. If you need anything else, you will have to modify the FPGA.

If signal strength measurement is mandatory for your use-case though, I am afraid you might not be able to use the Lighthouse deck.
rampudia
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Joined: Fri Mar 26, 2021 4:21 pm

Re: Using the Lighthouse deck for visible light communication (VLC)

Post by rampudia »

Ok thanks for the clarification!
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