Topic: Building a Sonar for iPhone/iPad

[dezguy]

Ok, I have a crazy DIY project and I'm interested to know if there are others out there researching/working on something similar.

I think it would be cool to create software for the iPhone that would be able to receive a real-time sonar signal, process the data and output to a fishfinder-style screen. Then be able to also record the data/gps information and download for later analysis. I think you could probably also use the compass and accelerometer.

Has anybody ever tried something like this before? I realize this is a huge project

I'm specifically interested in:

- Data specification coming out of a Humminbird fishfinder - i have the 110 model and I see there is an output on the back. Does anybody know if I can link this model to a serial port and read in the data.

- I think I could build a device that controls the transducer from an Arduino board. As anybody ever tried this?

- Humminbird sonar file samples. Does anybody have some good links?

- Information on signal processing. Does anybody have any good links?

- Is there any DIY or open source projects out there like this?

This isn't for a commercial product. Just curiosity based research; and I'd love to be able to use my iPad for real-time visualization...it's such a sweet device and sonar data would look COOOOOL on it!

Thanks in advance,
Mike

[mendota]

Unfortunately, there is no real-time sonar output on any low-cost sonar, including the high-end Lowrances and HB's.  The 998 and 1198's have a video output, but that is just WYSIWYG from the sonar screen, not at high resolution.

[keizerh]

something like

http://www.interphase-tech.com/pcview.htm  ??

hendrik

[dezguy]

Yeah that looks promising. Certainly it demonstrates that it's possible  to build an interface between a transducer and the computer.

My basic idea is this:

- I've purchased an Arduino board that will interface with my Mac
- I'd like to find an old fish finder that I can rip apart for the transducer
- Connect the Arduino board to send/receive from the transducer
- Have the Arduino board do the analog to digital conversion and create a serial sentence to send the data to Processing and graph it in real time

If I can get that working I'll seek to port it to Objective-C

Anything I'm missing?
-
- Use Processing to graph the data provided

[Fishton]

The Eagle Cuda 350 S/Map has NMEA0183 output capability that when connected to a serial to Bluetooth transmitter, can be received by any Windows Mobile device such as the Samsung Omnia for example.  The program I use for receiving this data is DrDepth.  It offers me a sonar view, Bathymetry - contour and 3D as well as temperature.

[bruno.rosa]

Dezguy

You will send / receive signal to transducer with microcontroler ?

Transducers needs high voltages / current to work, I build one distance meter with transducer to work at 7 meters, it needs 300 volts. HB uses 4000 W peak to peak in transducer, you will need one power controller.

Bruno

[mendota]

The transducer will do you little good by itself.  You need to tap into the sonar receiver signal, after all the signal conditioning stages.  Good luck identifying that without a schematic - hope you are good with a scope.

There is a significant amount of technology that goes into creating a clean sonar signal, and I doubt you want to try and duplicate it.

Once you get a clean sonar signal, then you could A/D it - but you might be surprised by the speed and resolution required of the A/D.  Not sure your development system can handle that.

As far as NMEA data, there is no sonar signal sent, just digital depth.  While you could make a crude "sonar" chart from it, it is not the sonar data itself.

[dezguy]

Bruno.rosa - Many thanks for the info. I see the Hummingbird 110 is 125 Watts (RMS) and 1000 Watts (Peak-to-Peak) with a range of 240 ft. If I could meet those specs I'd be happy. But I here what you are saying about the Arduino board not being able to output that directly.

Mendota - Good point on the resolution/speed of the A/D conversion, and thanks for the tips on the signal conditioning stages. I wasn't aware it would be so complex.

So is this a crazy or impossible idea?

[mendota]

Neither, just expensive and time-consuming, and doubtful you can readily achieve something better than you could buy for considerably less.

But it could be a learning experience, no doubt.

Hint:  If I were to attempt this, I would get an old flasher-type sonar - the simpler the electronics, the easier to trace and understand.  Flashers are entirely analog, no digital, so finding the sonar signal and a signal to trigger your A/D (AFTER each transmit pulse) should be relatively easy.

Oh yeah - the transmit pulse, as mentioned, is a high-voltage pulse - beware.  Probably not lethal, but it will hurt sensitive electronics pretty readily.

[dezguy]

Mendota, that's good advice to try a Flasher. I will see if I can find an old one. Thanks a bunch,
Mike

[dezguy]

Ok, I have the basic software built. I just need to figure out the hardware component.

I managed to snag an old Garmin off a friend. Does anybody have experience with how to drive the transducer?

[mendota]

Well, building a sophisticated sonar system is non-trivial, and significant training and experience would be required.  But basic, low power / sensitivity stuff can be done pretty easily.  Google "sonar circuit" and you can find some hints.

http://www.seattlerobotics.org/encoder/200211/autonomous_robotic_fish.html