I'd like to build a deep water temperature probe to be used when Downrigging for salmon. There are similar commercial systems out there like the Fish Hawk X4 but they cost almost $1000 (they include speed and depth as well).
The commercial unit uses a sonar transducer at 70khz to transmit a directional signal back to the boat where another transducer receives the signal and sends it to a display.
This seems to be a very simple task (remotely reading/displaying temperature) if it weren't for the ~150 feet of water between the probe and the boat.
Wired options pose many complications and isn't something I want to explore currently.
if modified, are these simple arduino sonar units capable of something like this?
there are also more robust solutions like this ... it's probably a lot more expensive though, and big.
Does anyone else have any ideas on how to approach this? I like the idea of modifying the ping frequency to use as the variable to transmit data. just not sure how to approach the hardware. I also want to keep the frequency above 400hz (Salmon are able to detect sounds below this and I don't want to spook the fish I'm trying to catch!)
I'm looking forward to any ideas or guidance you guys can come up with!
Thanks!
if modified, are these simple arduino sonar units capable of something like this?
Not at all. Those will operate only in air and cannot even be exposed to high humidity or the circuit board will quickly be destroyed.
For underwater acoustic communications, you must use transducers that are designed for operation in water, together with matching transmitter and receiver modules.
jremington:
Not at all. Those will operate only in air and cannot even be exposed to high humidity or the circuit board will quickly be destroyed.
For underwater acoustic communications, you must use transducers that are designed for operation in water, together with matching transmitter and receiver modules.
what if it was immersed in mineral oil inside a small vessel? still probably not enough power I'd guess. the Fish Hawk commercial unit transducer is visible inside the clear probe case, I can't seem to find anything like this
picture of probePicture of Probe
Side Picture of probe
For efficient transfer of energy the characteristics of the transducer must be matched to the characteristics of the medium (called "impedance matching").
Water is a very different medium from air.
http://www.benthowave.com/products/BII-7590broadbandtransducer.html
I'm inquiring about pricing on these. I imagine they'll probably be too expensive
