The Accuski/Perfect Pass solution...

[toyotafreak]

OK, at some point (whether it be in their unit or in our multi-function CPU), mechanical signals (pressure or vacuum) are converted to analog electrical signals and are then digitized. Their box simply adjusts servo output based on the difference between speed (desired) and speed (indicated).

All we've got to do is hack in (or ask them to) and recreate this digital speed signal using an off-the shelf handlheld GPS unit outputting velocity 10 times a second.

Might not work perfectly on a river, but it would never clog. All GPS systems (even the tiny ones that fit on little circuit cards) output velocities, and most can output faster than once per second. GPS is extremely accurate in speed and would be the sweetest of sweet solutions.

All I know is that my S22 requires constant attention at wakeboard speeds and since the motor's not a torque powerhouse, cuts to the outside really slow the boat down. I don't mind throttling it constantly, but when my wife and other unitiated tow, it's an e-ticket ride.

[davidgree1]

There is a gps for accuski, but I was told it only updates speed evry two seconds and is not faast enough to control speed.  I have accuski which I use on rpm mode during boarding. It works o.k. but you have to use the h/t toggle to adjust speed during the run.  It beats manually controlling the speed.  I moved the computer closer to the venturi bu this didn't help the system work in mph mode.  

[toyotafreak]

Spent a little time looking around and found that most handhelds and OEM board output at 1 Hz (once per second.)

There are a few that will output 2, 5 and 10Hz, but they're all a little pricey.

Once per second might work cool with a suitable filter. Would be much better if rates were at the very least 2Hz, with 5Hz and 10Hz behing preferred.

Good to know that they've tried it at 2Hz (this means they've probably got an interface built.)

[cyclone]

I know that on my MMDC box, the speedo tubes input directly. That is what has me stuck on designing an interface. I would have to go from an encoder input (square wave @ X number of pulses per revolution) for a paddle wheel speedo, back to a pressure signal. Not practical. If we had a digital input (GPS) or even a 4 to 20 MV analog signal input, I could easily make it work.

[toyotafreak]

The question is, what (and where) is the output of the A to D within the MDDC? Oncefound, we simply snip that baby and replace it with surrogates.

I haven't opened my MDDC. Doubt BorgWarner would send us much in terms of interface and functional block diagrmas. The alternative is opening the thing (at work) so we can break out the O-scopes, etc.