Anyone used a hydrophone succesfully? Have not found any for sale that are compatible with the UNO
RH
A hydrophone is just a type of microphone, you would interface like any microphone, ie an amp board of
some sort.
Thank you Mark. I realize it is just a microphone that can go underwater, the problem i have is nobody seems to sell one that is compatible with the UNO (one that works with the available voltage), and there are no videos or posts that suggest it is even feasible.
RH
nobody seems to sell one that is compatible with the UNO (one that works with the available voltage),
Their is nothing special about the Arduino that a device has to be compatible for it to be used. That is just a marketing ploy.
Just supply the hydrophone with the voltage it needs and ensure the output is within the 0 to 5V the Arduino can cope with. This means either using an op amp or a voltage divider.
Why do you expect everything to specifically say Arduino compatible?
As to videos, are you content to only do things people have done before? I find that a very odd attitude. Is this the way modern making is going? It is increasingly looking like it.
If you get stuck then we can help you get it right, that is why we are here.
Thank you Mike. The only reason I was looking for a video is because i'm very new to this, which explains why I am the one asking the questions instead of replying. I appreciate your suggestions, I'll give it a try.
RH
All microphones require a preamp to boost the few-millivolt signal to audio line-level (around 1V). That's just about right for the 0-5V Arduino.
Since the microphone connection is probably the easiest part of this project, consider getting a [u]microphone breakout board[/u] and do some "dry" experiments. The breakout board has a preamp and a properly biased output and ready-to-go.
If you don't want to build a preamp, the cheapest way to get one is to buy a [u]small mixer[/u] with one or more mic inputs.
Or, you can use the preamp built into your computer/soundcard along with line/headphone-out. But, the mic input on a computer is designed for an electret condenser computer mic and it might not be properly-compatible with a hydrophone.* I'd guess there's lot's of hydrophone equipment that's designed for connection to a computer. (Of course the Arduino doesn't have the same connections as a computer.)
Since the output from a preamp is AC (it swings positive and negative) and the Arduino can be damaged by negative voltages, it's important to [u]bias[/u] the Arduino input at 2.5V.
- I don't know what's standard for hydrophones... Computer mics are high-impedance unbalanced (2-wire) and the soundcard supplies 5V power for electret condenser mics. Stage/studio mics are low impedance balanced (3-wire) with an XLR connectior. Dynamic mics don't require power. Studio condensers get 48V phantom power from the preamp/mixer/interface, and stage electret condensers usually have an internal battery.
Hydrophones are generally expensive and usually piezoelectric, so they are quite simple to interface as receivers. As transmitters, expect to need high voltage (200-400V) electronics.
However, there are no standards, and very little has been published for experimenters so you will probably have some work to do, including trial and error. Fortunately the Chinese have started mass producing hydrophones at reasonable cost -- I've recently seen a couple on Alibaba for $30 or less.
Hydrophones are generally expensive and usually piezoelectric
In that case, a regular low-impedance microphone preamp won't work (at least it won't work properly).
Electric/acoustic guitars often have a piezo pickup and they work with a regular high impedance guitar preamp/input, or there are special even-higher impedance amps/preamps for this application.
You'd have to check the hydrophone specs and if possible make an estimate of the expected sound level and whatever that converts to in volts/millivolts.
DIY hydrophone, for recording sounds underwater (with preamplifier plans).
Thank you all for the replies. I appreciate the suggestions
RH