DIY cruise control (ala perfect pass)

GuitsBoy · Posted: Aug 15, 2005 6:40 am Post subject: DIY cruise control (ala perfect pass)

Has anyone made their own cruise control for a boat? I came across an audiovoxx cruise control setup for a car for under a hundred bucks, and I started thinking about how it could be adapted for use on the boat.

Im wondering if a paddle wheel speed sensor puts out a signal identical to a VSS sensor in a car... for instance can a paddlewheel speed sensor drive a regular car speedometer or is a boat speedo a special piece?

Secondly, the cruise control would only be able to open the throttle and not close it, so as soon as the cruise was activated, I guess you would have to back off the throttle to allow the cruise control servo a good range of control.

Next, I would have to have some sort of switch that would sense the throttle lever being pulled back into neutral (or close to neutral preferably) that would act like the brake switch in a car to deactivate cruise control

Anyone else have any ideas or possible concerns?

Thanks,
-Tony

AndyDeeJay · Outlaw Joined: 20 Jul 2004 Posts: 239 City: Belfast

Perfect pass works in reverse from a car cruise control in that you put in too much throttle and it pulls the extra back out. In fact if you have not enough throttle it will put ## ## ## marks on the display asking for more. I would be much happier in a boat with the PP set-up because a failure would be less dangerous - Can you imagine coming in to dock, the cruise control failing and going wide open throttle?

I think this topic has been covered before and the main concern other than the above mentioned was that the power vs. speed control curve for a boat's planning hull in water is so different from a car's wheels rolling up/level/down the road. Without access to PPs aggression charicteristics and paddle wheel sample rate, I think a car cruise control would be more trouble than it's worth.

GuitsBoy · Posted: Aug 16, 2005 3:42 am Post subject:

The first concern would be handled by a neutral sensing switch which would act like the brake pedal in a car, disabling the cruise control.

The second concern is a bit more difficult, but I dont think its as much of a problem once the boat is up on plane. I mean a car's cruise control works on different gradients. Itll try and keep the same speed going up or down a hill. The excess drag at lower speeds should simply look like the boat is "going uphill".

I just wish PP wasnt so darn expensive.

Wallrat · Posted: Aug 16, 2005 4:35 am Post subject:

I definately think its worth looking into. I'm sure it can be done, but the real question will probably come down to time and money. If you were concerned about cruise control failing and going WOT, put it on a relayed switch. Although I've had cruise control on several of my vehicles and have yet to see cruise control just pop on. Equally disasterous results would apply and I'm not sure how rigging it up in a boat would be any different.

The major hurdle will be figuring out if a paddle wheel provides the same signal or if you'd have to build some type of circuit to make it compatible.

GuitsBoy · Posted: Aug 16, 2005 4:49 am Post subject:

Dont forget there's always the lanyard kill switch which overrides everything, however I dont forsee too many problems if theres both a neutral switch as well as the normal cruise control deactivate button.

As for the paddle wheel, this is my biggest hurdle as i am not an electrical engineer. I figure if all else fails, I could fabricate a larger paddlewheel that trails behind the boat, sort of the size of a training wheel with fins on it. I could put the magnet and hall effect sensor that would normally be affixed to the cars driveshaft on the big paddlewheel, as it should turn at similar rates as a cars driveshaft at highway speeds.

Juice75 · Outlaw Joined: 09 Jul 2004 Posts: 218 City: Austin

There is an Audiovox CC version that doesn't need a speed sensor. You can run it in RPM only mode. It's not as precise as speed control, but still pretty close. It's like running PP in RPM mode. Here's a link to it. You could also put the magnets on the driveshaft of the boat, if you don't want to mess with making a paddle wheel. Also not perfect, but better than nothing.

http://www.jcwhitney.com/autoparts/Product/showCustom-0/Pr-p_Product.CATENTRY_ID:2001597/c-10101/Nty-1/p-2001597/Ntx-mode+matchallpartial/N-10101/tf-Browse/s-10101/Ntk-AllTextSearchGroup?Ntt=cruise%20control

GuitsBoy · Posted: Aug 16, 2005 10:28 am Post subject:

Thanks for the info juice. My first reaction was that this would only be about as effective as simply not adjusting the throttle throughout a run. Theres too much slippage from the prop, whereas wheels wont slip like that. But as I started to think about what actually happens during a run, as you start to turn, as you come out of a turn, and speed creeps up, etc... It started to look like a more useful tool. It wont help any when the boat bogs in the turns, but it will keep the rpms from drifting up on the longer straights.

I still think id like to get it working with a normal paddle wheel first. The more I think about it, the more i like the chances of it working. The paddle wheels will be spinning quite a bit quicker than a normal speed sensor would on a real axle, but the reax axle in turn has ~100 teeth or so on its reluctor wheel. So if you figure, they both probably send a similar number of pulses per minute while the respective vehicles are at their inteneded speeds.

Does anyone know where to get a small paddle wheel speed sensor?

Fishmaster · Posted: Aug 17, 2005 10:24 am Post subject:

I thought about this also a while back as I had installed one of these on my Toyota truck in the mid 80's. If I remember correctly it had a servo motor that tied into the throttle linkage from the pedal, which was the hard part of the install, and it had a magnet that attached to the driveshaft that was easy.

If someone can figure this out you will be a hero.

nan0 · Criminal Joined: 08 Aug 2005 Posts: 55 City: San Jose

So I've been thinking about the paddle wheel idea as well. I've got a boat with a paddlewheel already in use (Garmin fish finder). I haven't been able to find any information about the speed wheel online yet, and will have to get the boat owner's permission (dad) before probing around.

Read through the install guide for perfect pass, think i've got a decent idea how it works. Can anyone get some pictures of the throttle servo motor setup for perfect pass? some hi res pix from multiple angles would certainly help. Best would be out of the box pictures of all supplied parts Wink

-=LoneStar=- · Addict Joined: 20 Nov 2004 Posts: 751

Here's the wheel they use with PerfectPass: http://www.airmartechnology.com/cataloginter.asp?PageNo=111

It makes about 14,800 pulses/mile.

Here's the Audiovox install manual: http://www.audiovox.com/manuals/owners/2239.pdf

It has settings for 2000, 4000, or 8000 pulses/mile. So, if you could make a circuit to cut the signal frequency in half, I think you'd be good in that area--the exact frequency isn't important as long as it's close. I also noticed, however, that there are a bunch of switches to tell the unit what kind of engine and transmission you have. I'm sure this is so that it will know how much to adjust the throttle so that it doesn't over or under correct and hunt around too much. We don't know if any of these settings would provide a consistent speed on a boat so someone would just have to hook it up and try all the settings to see which (if any) works best.

-=LoneStar=- · Addict Joined: 20 Nov 2004 Posts: 751

Update: I just saw on this page...

http://www.airmartechnology.com/uploads/catalogPages/cat_112.pdf

...that there is optional pulse division circuitry or different pulse rates so maybe you wouldn't have to make your own circuit after all.

Wakebrad · Ladies Man Joined: 11 Dec 2003 Posts: 12257 City: Dallas

GuitsBoy, if you could figure that out it would rock! PerfectPass is all markup. They charge that much because they can. If you could come up with plans easy enough to build your own for ~$100 that might even force them to lower prices.

mneal · Outlaw Joined: 28 Jun 2003 Posts: 120 City: St. Petersburg

I thought about this a while ago, but got busy and sorat forgot about it until I rad this thread. I think the linkage is the largest challenge, the PP pulls the throttle to the setting of the boat cable, it is opposite what a auto does. It needs to have a return spring or something thast is the lickage comes off or there is a failure the throttle gets returned to idle and not opposite. I found a over seas company that makes custom cruise controls for ATV and off road vehicles and they semed willing to dea with me in regards to adjustment speed etc. A hall effect sensor is definaly the way to go, ust using RPMs will not compensate for prop slip % and will be crap control at low speeds. I wil try to dug up the contact info of the overseas cruise contol guy if you want.

GuitsBoy · Posted: Aug 22, 2005 8:42 am Post subject:

I dont think youd really need to drop half the pulses at all. In fact it may be better off this way. A car may generally cruise at 60 MPH and will see those 4000 or 8000 pulses every minute. A wakeboard boat will only do 20 to 30 MPH and will only see 4933 - 7400 pulses per minute using the airmar sensor. This would probably jive perfectly.

Also, I dont think there were many settings regarding the exact specifics of the engine. It was my underdstanding that it was more along the lines of a 3 position switch for high, medium and low horsepower engines, so as to keep from over compensating. Im sure this dosnt have to be perfect, and i bet that its also a lot less noticeable on the water as opposed to the highway.

GuitsBoy · Posted: Aug 22, 2005 8:54 am Post subject:

I agree that the linkage will be the greatest challenge. Looking at my boat this weekend I saw that the throttle cable is a rigid push rod where it meets the throttlebody / carb. Its not a simple cable on a spring loaded butterfly like on a car. Ill have to do some more thinking on how we can get around this, and more importantly, how we can override the cruise in panic scenarios. Maybe a strong servo motor that has some sort of a friction grip on the throttle cable. Something strong enough that it could move the throttle cable and controls alltogather, but something that could be easily overpowered... hmm

mneal · Outlaw Joined: 28 Jun 2003 Posts: 120 City: St. Petersburg

Darn it, I was hoping on of us would have figured out how to do the throttle by now. Very Happy

As always got busy working 70 hr work weeks and did not think about this for a couple monthes....soon it wil be wakeboarding season again and I am close to just buy PP Pro....just chaps me to spend 1100 on like 300-400 dollars worth of technogy...it does not/should not cost that much.

alejandro · Newbie Joined: 11 Apr 2003 Posts: 33 City: Bryan

GuitsBoy, don't waste your time and money. I tried it with the standard audiovox cruise control, and with a rostra with stepper motor control instead of vacuum. It was not hard to install. I put a paddlewheel in the hull, safety switches, etc.
It should have worked fine. Except that it is really slow. I guess the programming doesn't take the approximation speed so it could not keep speed, I would set it at 21 mpg and the cruise control would wait 'till the speed dropped a little to start correcting, by the time it was opening the throttle, the boat was at plowing throught the water at 14 mph. Then it would fully open the throttle and go all the way to like 27 mph, and down again, it could never find the right speed or keep it anywhere close, even at the lowest setting of pulses per mile. there was less fluctuation with it off and the throttle left in the same position once the speed was achieved. I logged it and it looked awful in Excel. Accuski works the same way, opening the throttle instead of closing it like PP, I think shortline is the same. I would invest the money of the cruise control, buy some stock that's going to do very well, and then sell when it peaks and buy a PP

MrBlean · Posted: Mar 31, 2006 6:20 am Post subject:

Spot on alejandro. If all the guys who are spending hours trying to fathom out how to save 400 bucks on buying PP put the same hours and effort into a part time bar job they could easily afford to buy PP at full list price and get a product that works with no bugs, glitches are potentially disastrous failure modes.

Sure, PP is expensive for what it is but they've put the work into a product that, until wakeboarding came along, was a really small niche market (slalom ski course boats only) and did a damned good job on it. They got lucky with the wakeboarding boom and no doubt, are making a decent return. The fact that it remains a small market explains why there are no competitors - the investment required to catch up to PP isn't warranted by the sales volume/value.

Great to hear from someone who has actually tried to build one himself and formed the same conclusion I did - it's not worth the effort. C'mon guys, swallow your pride, open your wallet and buy a product that is proven and works.

wesgardner · Posted: Mar 31, 2006 7:01 am Post subject:

Hey Jeff,

Right on...

Wes

alejandro · Newbie Joined: 11 Apr 2003 Posts: 33 City: Bryan

Well, there is a competition, I have also tested an accu-ski. It works well for slalom or wakeboarding with a light boat. It is not that good when you weigh down the boat or want to go slow for beginners or wakesurfing. Accuski has a very bad throttle interphase too. I had to make my own (which was the one from my failed cruise control experiment). I haven't given up on alternatives by the way. Now that many engines have electronic throttle control (a servo or a stepper motor controlling the throttle plate), some companies (Malibu and Mastercraft among them) are building their own cruise controls, which shows it is not that difficult.

thebulkhimself · Newbie Joined: 31 Mar 2006 Posts: 9

I'm sorry but the comment "Swallow your pride and open your wallet" is just crazy!!!

Anybody who doesnt look for a cheaper alternative will have the nicest gear and to go with it the longest working hours (ie less boarding hours), the largest insurance costs and the smallest wallet.

Sorry to be candid Cool

alejandro · Newbie Joined: 11 Apr 2003 Posts: 33 City: Bryan

I have to agree, I am always looking for ways to improve my boat without spending much. It normally entails making a lot of modifications on the boat (even exchanging engines or cylinder heads some times). Status quo sucks, expensive things aren't much fun if you have to give up a lot of other things you like. If I want it, I try to make it first...