Axis Wakeboard Boat Forum

So I've been kicking around an idea to build a surfgate transfer horn. Figured I'd start a thread to document my progress.

DISCLAIMER: I AM A SHADETREE HACK AND BETTER PEOPLE WILL LIKELY IMPROVE UPON MY FREQUENTLY BAD EXAMPLE. NO WARRANTY THAT THIS WILL WORK AND DECIDING TO MODIFY YOUR BOAT IS ON YOU. PROCEED WITH CAUTION!!!

I'm starting from the understanding that surfgate actuators are reversible, such that the positive and negative signals to the actuators will "flip" between deployment and retraction. So what I want to do is figure out which wire is positive when an actuator is retracting. My idea is to use that positive wire as a signal for a programmable trigger relay that will in turn trigger a horn and or flashing light.

DOWNSIDE: unlike the malibu horn, this horn will go off every time the surfgate retracts (for instance, when you cut throttle to pick up a dropped rider). Will that make this project ridiculously annoying? Maybe so!

Anyhow, I've started assembling the parts:

positaps to tap the "positive on retract" SG actuator wire.


PAC TR12 Trigger Module


Moped Horn


Thoughts, criticisms, ideas, and other helpful hints welcome!

On the issue of having it go off every time you come off plane, I guess I could get a window switch like this one: https://www.summitracing.com/parts/sum- ... fgodyyQJ0w

Then set the switch to be normally off and turn on when I reach surf rpm. That way if an actuator retracts when throttle is cut, the transfer horn wouldn't have power, so wouldn't work.

Very cool!

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I would use a piezo alarm and /or a diode to set this up to only indicate extension and not retraction.

Additionally i would NEVER put a relay on that module's output, because it is not likely to be protected from the voltage spike released when the power to the coil is removed. Use a solid state relay if you are hooking to a high current horn.

If you are still going to use a coil relay, put a diode across the coil that is back-biased in the normal direction to catch the flyback-voltage. Of course this needs to be downstream of the isolation diode mentioned above.

Hmmm... PAC doesn't recommend a diode on its diagrams? http://www.pac-audio.com/downloads/tr12 ... 060315.pdf

That said those moped horns are a 1.5A draw, and the pac module will do 3A. I'm probably going to put the horn on a relay anyway (overkill and all), but I don't think I have to.

Here is some warning notes on relay coil supression:

http://www.te.com/commerce/DocumentDeli ... DocLang=EN

PAC-AUDIO does not say if they have supression already, but they might. If so, there is no problem. I would call them and ask if they are protected against inductive loads, just in case.

In the app note above, the relay was generating a 750 V spike that went to 0.7 V with a diode. Much safer for your electronics. When you hook up the horn, it will be throwing spikes like there is no tomorrow - so it is a really good (GREAT) idea to have the relay drive the horn. I would even put a local capacitor at the power terminals of the relay to keep that noise from getting too far into the rest of your boat's electrical power. Might make nasty noise in the stereo, for example.

Subscribing to this, I wanted to to this for a long time. Curious what you'll come up with.
What about getting the activation signal from the surf gate switch instead? This way you don't have the problem of the horn triggering everytime you pick up a rider, just once on first switch activation.

great idea!

This project has stalled a bit with family commitments, but I want to get back at it in the coming weeks.