DIY Perfect Pass

[jwroblew]

The reason I'm suggesting throttle position is because I have a Perfect Pass, RPM, system right now and it takes to long to settle in. For wake boarding it is fine but for skiing it is not. Were I ski the set up into the slalom course is short so getting it dialed in quick is a must. To stop over shooting increasing the sample rate should help a ton, a sample every second wont do, I think every 0.1 secs would work. The problem with the PP RPM system is you have to get the throttle close to were it needs to be, or the servo motor has to work with a lot of cable to get the speed / rpm correct, which takes time, plus it always under swings as you pass through the desired RPM. Going to a known throttle position should greatly increase the settling in speed.

I think both TPS or RPM systems will have to learn. To use your example the TPS would have to learn the relation between throttle position and increase in speed, for example maybe the 2% change in throttle position is a 1 mph change. Likewise, RPM system would have to learn the relation between RPM and speed, a 200 RPM change maybe a 2 mph change in speed. I think a TPS system would learn quicker since it would not have to worry about how long it takes the engine to rev up or down, also I think it would be a smoother engagement. Either way sample rate is the key for the system not to hunt.

And if you have an older boat with out a TPS, I think a string potentiometer would work great for getting throttle position.

Turbohojoe, is there any way to get your source code?

[smitty1258]

bump its nearly mid july.

[turbohoje]

sorry... 3 jobs. no time. not even getting time to board at the moment.

i passed some probably worthless code over to a guy named Jason. maybe he'd throw an update up here if he has any.

one of these days i'll make some progress

[smitty1258]

jwroblew

^ that guy?

[smitty1258]

hopeless bumo

[turbohoje]

i keep gaining and loosing motivation to get this going. i know its going to be some degree of testing to get it right but any time i get on the lake i would rather be boarding.

this last time however, the driver couldnt keep a decent speed and i attempted a backroll at 25 pulled on one of my knees. i'll be off the boat for the rest of the week so maybe i can get some progress underway on this.

[smitty1258]

ouch but good for the rest of us?

[smitty1258]

[turbohoje]

here's the last update

the digital counter on my PLC is a ground triggered and the rpm pulse to the tack at the dash is ~20V+. i have not even bothered hooking them up directly bec i think the result will be buying another PLC.

two small hurdles:
1) above mentioned positive 20V to ground triggered transistor circuit
2) waterproof recessed dash enclosure. the newly added 200lb of sand in the tip of my boat adds to the splash factor and i dont think the display would survive very long. cell phones in the top cup holder get the occasional water treatment and express their dislike with the situation.

[Ridesteady]

Sorry to resurrect his thread, but I wanted to add my $.02.

You guys are kindred spirits with me. In fact, I started out much the same way you did, "Why does PP cost so much?? I can do this for better and cheaper!"

It turns out that it took years longer and cost way more money than I ever imagined to get it right. Good, reliable, marine-tolerant hardware is certainly a challenge, but the software control algorithm is where all the magic secret sauce is.

And, as some have found, if you try to do it yourself, plan on spending close to or even more money than it would cost to just buy an aftermarket boat speed control, and it likely won't work very well. I did the exact same thing, but I finally decided to make it my mission to get right and I quit my good engineering job to do just that.

Anyway, best of luck to y'all, and if you're still working on it and get stuck, give me a call. I can probably give you a couple pointers.

Thanks,
Justin Muessig
CEO, Hydrophase LLC
www.hydrophase.com

[turbohoje]

Every now and then I get an email about this, and I haven’t been checking the forum for quite some time (my apologies). I’m actually still on this project after so many years but it’s evolved a little for me. It is impressive how many hackers out there also want to tackle this kind of project, if there is a way we should collaborate and benefit from each others skeels.

I no longer have that boat, the new one is MUCH better at sticking to a speed as it’s not an IO. An orangutan (or random drunk friend) can give me a great pull on a wakeboard (set and forget), but I’m picky when it comes to the foil so I’m still interested in doing this project. The new boat makes my adjustment algorithms easy peezy.

So this new boat does not have a working speedometer. Before the season starts, i'm wanting to build a gps based one that will fit into its new proper dashboard (not just a cell phone in a cup holder). My old boat’s dash looked like the back to the future car and I didn’t much care what the display was going to be, this one I don’t have the desire to cut holes in glass for buttons which motivates the touch screen stuff.

What I would like to do, is CAM out an enclosure that will hold an ardiuno and a display. I have not yet found a display I like that will fit into well into a 3.5” circular enclosure very nicely. My thought is to make something pretty versatile that can be re-purpsed for whatever, gps speedo, telems, whatever. Touch screen would be great, but it may not be feasible. The screen should be weather proof, reasonably priced and visible in the sun. All 3 are not easily accomplished.

I’m not very adventurous on the internet. I pretty much start and stop by parts search at sparkfun.com. there is a bevy of things at digikey and mouser, but they don’t come with email tech support and documentation.

My fall back plan: Autozone + dremel + cheap display + arduino

I should have posted the code, it’s long gone (github, I get it). I don’t remember what platform any working code was on (msp430, rabbit, or arduino). I’m partial to arduinos as there is a pretty decent community for development on those.

I’m still at turbohoje.hotmail if you want to rap about stuff.

[TeamAllen]

You guys are impressively hard core about this.
Not to take away from your project, but there is a group buy going on with a Perfect Pass speed control system.

[Stunt Driver]

Why not resurrect?
Please welcome new entrant on list of people trying to re-invent the bicycle here. Or PP in this case.

I did not find any finished implementation of DIY PP, something actually installed on boat and functioning, unless i missed something?

My goal: to be able to input speed accurate to 0.1mph as number (vs just blind cruise control), and have my Kruzo keep speed as accurate as posbible, no worse than 1mph +/-.

Planning to use Arduino, with combination of inputs paddlewheel/GPS/RPM sensors, with RC servo as actuator.

Fitting all this on IO bayliner 18 feet.

My first bench test draft is in video here (by the way let me know if my spoken english is understandable, don't be afraid to hurt feelings).

Any comments welcome!

My main challenges - algorithm.
Do I bother with derivatives?
And should RPM be used as second input for greater accuracy too?
If anyone mathematically smart can help with model (function) for sw testing - that would be best.
I'm in Oregon, so not getting on water earlier than APril.


http://youtu.be/TCs_7v0AUik

[Stunt Driver]

Much progress on my side. updates here http://steadypass.webs.com/

May even be available as a kit after all. It is not going to be an ultimate ski system, like PP, but should be good enough for a smooth pull at steady speed, with digital input/readout, and few other convinient features on display.