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Some questions about CC85XXDK-HEADSET for an underwater intercom for divers project

Emmanuel DURANDY
Prodigy 30 points


Hello TI community,

It's been awhle I'm looking for an embedded device to build an underwater intercom for divers.

The CC85XXDK-HEADSET can fit to my project, as it is bidirectionnal, but I have some questions.

a) What is the RF output power of the CC85XXDK-HEADSET? What will be the distance range in salt water?

b) What is the sensivity of the audio interface input, i.e. can I  connect directly a dynamic microphone or it needs a preamp to have "line in" level (1 Vpp)?

c) Is it possible to configure slave or master (or both) in a kind of "VOX control", to avoid acoustic feedback? (such a level detection on the mic input that enable emiting signal)

Thank you for your help.

Best regards

Emmanuel.

  • 0
    TI__Expert 3240 points

    Hi,

    I don't think that PurePath will give you the range under water that you are looking for. PurePath is operating in the 2.4 GHz frequency band, which has a very poor range under water. I don't have any data on the specific range for CC85xx, but in I would guess that in general the range is well under 1 m for a 2.4 GHz system in salt water. Maybe even under 10 cm for most systems.

    Best regards,

    Johan 

  • 0 in reply to Johan Gustafsson
    Prodigy 30 points

    Thank you Johan for your answer.

    I received my PPWA evaluation kit today. It works perfectly but I'm dispointed that it won't work underwater. I need a short range (10m). Whatever i will try to integrate the 2 PCB in waterproof box and test it.

    Best regards

    Emmanuel

  • 0 in reply to Emmanuel DURANDY
    TI__Mastermind 21125 points

    Hi Emmanuel, 

    It will not work at 10m..my bet is not more than an inch or two.
    Came across this paper why googling the subject:

    Underwater Wireless Sensor Communications in the 2.4 GHz ISM Frequency Band
    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3355409/

    PPW differs from 802.11b/g in many ways (modulation, output power etc), but since the most limiting factor is the 2.4 GHz wave-length not propagating well in water it's not a bad study.

    Regards,
    Kjetil