BLE signal for underwater application?

[vishal]

Hello,

We have developed our application which included sensor and receiver using nRF52840 with SDK15.0. Sensor will goes underwater up-to 100meter depth level and transmitting data to receiver which have above of water.

But we observed when we put device into water then within few feets the BLE signal not getting. 

Actually I have read this click here they said underwater 63% signal losses, So nRF52840 long range mode upto 400-600meter. If 63% of 400m = 148meter range will get underwater but not getting.

Can anyone please provide How we communicate with wireless underwater upto 100meter atleast? 

If we used Zigbee protocol to communicate with both Is it possible to achieve 100m range underwater?

Thanks....

[awneil]

You really can't hope to get long range at 2.4 GHz through water - it's the laws o' physics, captain!

See:

 https://devzone.nordicsemi.com/f/nordic-q-a/48826/using-nrf52840-to-send-data-over-open-sea-surface

Also:

https://www.google.com/search?q=2.4ghz+radio+propagation+through+water

In particular:

Underwater Wireless Sensor Communications in the 2.4 GHz ISM Frequency Band

[Erik_pxq]

Radio waves(Bluetooth) propagate really bad through water, just like you have experienced.

You will newer reach 100m with 2.4Ghz radio waves, I suggest you instead look into ultrasound communication.

Best regards, Erik.

[awneil]

vishal said:

I have read this click here they said underwater 63% signal losses,

What they actually said is,

"the 1/e (63% loss) occurs in 1.4cm"

ie, after 1.4cm, you've lost 63% of the signal!

[vishal]

Thanks for prompt response.

Ok, zigbee protocol also used 2.4GHz freq this option also can not used. Will you please suggest me how I can do communicate using ultrasound. Is it available some module for both side as like zigbee.

If yes so I can interface with nRF52840 and will communicate underwater. We just want to send some message which is short length.

Thanks..

[Erik_pxq]

Sorry, I do not know much about ultrasound communication, so can not help you.

Best regards.