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Moooools
01-26-2010, 12:07 PM
Hi

I have a bit of experience with the basic stamp, but I am starting to confuse myself with all the different types.

I will be using it for launch control andĚspeed conrol for a V8 ski Boat.
The throttle connection is going to be hydraulically actuated, so it will need to run the following (for an idea of pins required):

Hydraulic Pump Fowards
Hydraulic pump Reverse
Hydraulic solenoid valve
GPS Module ( Item 28146)
Water speed paddle (1 pin)
2x16 LCD Display
Activation switch
4 set up switches
Emergency stop switch
And a few spares for expansion.

It will need to be fairly quick aswell bacause it will have full governence over the speed of the boat.

So which module would be the best. I am on no budget.

Any help much appriciated,
Max

Ken Gracey
01-26-2010, 12:24 PM
Moooools, it sounds like you'll need more than 16 pins, so the BS2p40 is in your future.

But what we'll really need to understand is whether or not these activities need to happen concurrently. For example, it could become quite difficult to read the four setup switches while you're receiving a GPS string. And, the project is a large one, so it will need to be broken into small pieces to make it work. I can see how several of these functions could be grouped nicely, such as the hydraulic pump control. The LCD will hold characters, so it can be updated periodically. But do the hydraulic pumps require some sort of constant proportional control?

I have a feeling that others will recommend the Propeller, but I take it from the number of your posts that this is your first major project. If it is, maybe it's best just to forgo the whole "can a BASIC Stamp do it?" discussion and simply use a BASIC Stamp until you are out of resources. In the process you'd learn much about the interface to the various devices and really understand which parts need to run on their own, either in a second BASIC Stamp or the Propeller.

So, break it down into pieces that can work together. Make them work in groups, then try to integrate it in entirety.

Controlling a V8 boat is also quite dangerous if your hardware and software are not properly designed, but I'm sure you've already thought about this issue.

Ken Gracey

Moooools
01-26-2010, 03:36 PM
Thanks Ken

Yes I have thought at great length about the safety of the boat, and it will have a mechanical shutoff of power to the pump, and a mechanical valve to redirect the hydraulic flow.
The Switches will only be used for set up, apart from the switch for Speed control On/off and the emergency stop, which will have to be monitered.

This is my first major project, but I have all the time in the world to tick away at it, as we have yet to build the boat to put it in.

As for the grouping idea, that sounds like a good start, The setup can be run by itself as it will only be needed when the GPS, pump and other switches will not be needed. and then the LCD, and four setup switches will not be needed while the boat is underway.

As for the hydraulic pump it only needs to be ON or OFF but the it will need to be timed. Sort of an inverted pendulum sort of thing, but it does not need to be run so accurately.

I have a good feeling the basic stamp will handle it, but then again I don't know much.

Thanks for the help, and let me know any other thoughts
Max

stamptrol
01-26-2010, 08:59 PM
It will be an interesting project and will be a great learning experience.

As was pointed out, probably the Stamp will work with some grouping of the i/o and care taken that the program loops check the appropriate inputs often enough.

One important point, a real E-stop would never depend on the program for proper operation. Its important to distinguish between a "soft" e-stop which is useful for telling the Stamp or other processor that an e-stop is called for and a real or "hard" e-stop which shuts the system down regardless of the state of the program or processor.

Cheers,

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Tom Sisk

http://www.siskconsult.com
Ě

James Long
01-26-2010, 11:07 PM
Moooools,

Being a product of automation (that is what got me interested in micro-controllers), I have some concerns with your plans.

First, the most important item that you list is the throttle, and direction control. Hydrostatic is probably the worst method to drive the throttle and the direction shift. One of these would be better suited to a mechanism which is less likely to fail in a catastrophic fashion. For instance, if a hydraulic line blew (pump failed), the throttle and direction (forward/neutral/reverse) could be come uncontrollable. That would leave the boat possibly barreling down the lake/river while the operator takes time to fix the situation (mechanical means of moving one or the other) or hitting the E-stop.

Hydraulics are the easiest to consider, but are generally the least reliable. They are also the least efficient (more electrical power in, than the advantage you get out). They are typically hard to control (distance......where to stop....how long to let it move, not easily repeatable), unless using a pretty expensive neutral spool valve (Parker brand......they make nice proportional ones).

I suggest you place the E-stop to the ignition (hard wire). That way if something does go awry, you can stop the boat in pretty short order.

Just as a suggestion, the best practice for anyone working on a project, such as yours, is to make a list of "what if's". That will help you determine some of the necessary thoughts on the design and programming.

I'm not preaching to you, I am merely offering suggestions that many people do not think about.

Just to show you I like the idea....you could probably ditch the hydraulics, and google "servo city". They have some nice large servos (or even larger servo frames) which would be extremely easy to control, and are pretty fast. They have a significant amount of torque, and would probably be much easier to deal with than hydraulics (less weight too). You would need to make sure and waterproof them well.

I would like to know more about the project, for I could offer some more suggestions (like monitoring engine RPM......could be important in certain applications......and not that hard to do). But if you have reasons for not expanding on the idea, I understand completely.

James L

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James L
Partner/Designer
Lil Brother SMT Assembly Services (http://www.lil-brother.com)

Are you addicted to technology or Micro-controllers..... then checkout the forums at Savage Circuits (http://www.savagecircuits.com). Learn to build your own Gizmos!

Moooools
01-27-2010, 03:27 PM
James and others

I have certainly thought at great depth about the what ifs of this project. And I am aware of what could happen if I don't get it right.
So thank you for your concern.
As for the hydraulics, I only really thought of that because that was what our previous boat had for its auto pilot (direction control). I will not pretend to be an expert or even to know anything at all about hydraulics so I will heed your advice.
As for the servo idea, I would most definitely like a mechanical link between the throttle lever and the carb, as it is safer and also provides more feel. I do not want an electronic link, if you get what I am saying.

As for the E-stop on the ignition wire I think that is very wise. And I was thinking of having more E-Stops beyond the one on the controller. But I had not though of the ignition one.

I can not get it through my head yet how to keep a mechanical connection with using a servo, but tell me if you have any thoughts on how to do this.

As for more info on the project, The boat is a glen-l designs 16' missile.
The engine will most likely be an LS2 although I don't know yet.
If there is any other information you need feel free to ask.

Thanks for all the help, please keep it coming.
Max

James Long
01-27-2010, 07:08 PM
Moooools said...
James and others

I have certainly thought at great depth about the what ifs of this project. And I am aware of what could happen if I don't get it right.
So thank you for your concern.
As for the hydraulics, I only really thought of that because that was what our previous boat had for its auto pilot (direction control). I will not pretend to be an expert or even to know anything at all about hydraulics so I will heed your advice.
As for the servo idea, I would most definitely like a mechanical link between the throttle lever and the carb, as it is safer and also provides more feel. I do not want an electronic link, if you get what I am saying.

As for the E-stop on the ignition wire I think that is very wise. And I was thinking of having more E-Stops beyond the one on the controller. But I had not though of the ignition one.

I can not get it through my head yet how to keep a mechanical connection with using a servo, but tell me if you have any thoughts on how to do this.

As for more info on the project, The boat is a glen-l designs 16' missile.
The engine will most likely be an LS2 although I don't know yet.
If there is any other information you need feel free to ask.

Thanks for all the help, please keep it coming.
Max


Max,

I believe a mechanical connection could be retained if you drive the control with a servo (manipulate the carb via the control, not directly). I know of an instance this was done recently, but not sure if it totally applies in this situation. The control lever would need to be modified to where a servo could be engaged to drive the lever should you want automatic control. It could be as simple as having a pin you push in to engage the servo to the control lever. You could use a magnetic coupling device (permanent magnets), but then you would be manipulating the servo all the time (when using manually), and that is not good for the type of servo I had in mind (gear drive type). You could use a electromagnet engagement system, but then you are back to a possible loss of control should that de-energize during use.

As for the E-stop, I would make every E-stop button a step in the loop for the ignition (all in series). Then if any are tripped, the ignition will stop firing. That is pretty simple .......just use the wire which powers the coil. This is the same principle as a commercial E-stop.....all of the E-stop buttons are wired in series controlling a main power relay. If any are tripped, the relay de-energizes to stop the whole machine (removes all power).

Sounds like a very interesting project, but I must ask.....why???

I would understand if you were building an autopilot on one of Glen L's large cruisers, but it is unusual to not be at the helm of a smaller boat......there are very few places to visit on a small craft while underway. http://forums.parallax.com/images/smilies/smilewinkgrin.gif

James L

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James L
Partner/Designer
Lil Brother SMT Assembly Services (http://www.lil-brother.com)

Are you addicted to technology or Micro-controllers..... then checkout the forums at Savage Circuits (http://www.savagecircuits.com). Learn to build your own Gizmos!

Post Edited (James Long) : 1/27/2010 11:13:20 AM GMT

Moooools
01-28-2010, 04:52 AM
Okay. I see where you are coming from.

I think servo will be a better way to go. I will have a think on that one.

As for why: it is not so much of an auto pilot as it has no control over steering. there are a lot of people who can drive a boat, but very few who can drive a ski boat. Steering is easy it is the throttle control that is the hardest. So the idea is to be able to set up a launch control to pull the skier out of the water properly and then to be able to maintain a constant speed with ease. Also, there are so many factors affect the speed of a boat, it would be nice to just let the processer take care of it.

Thanks
Max

James Long
01-28-2010, 05:20 AM
Moooools said...
Okay. I see where you are coming from.

I think servo will be a better way to go. I will have a think on that one.

As for why: it is not so much of an auto pilot as it has no control over steering. there are a lot of people who can drive a boat, but very few who can drive a ski boat. Steering is easy it is the throttle control that is the hardest. So the idea is to be able to set up a launch control to pull the skier out of the water properly and then to be able to maintain a constant speed with ease. Also, there are so many factors affect the speed of a boat, it would be nice to just let the processer take care of it.

Thanks
Max


Ah...I see. I never thought about the speed control of a ski boat. I have been skiing about as long as I have been riding a bike.....and have been driving a ski boat for about the same time. It is a natural thing for me I guess.

You may want to add one more sensor. I ski rope tension sensor. If a person set the system to "launch" with the ski rope not taught, there would be one unhappy skier sitting back there. I have had it done to me before with a skilled driver.....so I know it is easy to occur. I know I have done it several times as well.

The ski rope tension sensor shouldn't be that hard, but it will depend on the rope connection point. If using a bridal, it will be somewhat more difficult. If using an arch or pole, it should be pretty easy.

Although with the tension sensor, the uncoiling of rope while hopping off the top of a boat house will not work. I had a friend that did it all the time....it was a hoot to watch. The girl never got wet. She started from the top of a boat house (it was a patio on top), and she sat back down on the pier/dock after letting go. She would do it all the time.......I was never brave enough to try......figured I would hop to late or too early. She would even slalom starting that way....but she wasn't successful every time with only one ski. Hitting the water with the ski level, is much more critical when only riding one, at least by my observations.

I had an uncle which could ride a frisbee as well.....try that sometime. I've tried.....it's almost impossible. It's harder than barefooting. Your feet are way too close together.

Anywho....enough off topic........

James L

James L

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James L
Partner/Designer
Lil Brother SMT Assembly Services (http://www.lil-brother.com)

Are you addicted to technology or Micro-controllers..... then checkout the forums at Savage Circuits (http://www.savagecircuits.com). Learn to build your own Gizmos!

Moooools
01-28-2010, 04:18 PM
That is a very wise thought. Although no boat houses around us, just beaches and water. So it should work jus fine.
And yeah we are all pretty fine behind the controls but it would just help us out in the sub perfect conditions we are used to. Or if we stick an inexperienced driver behind the wheel.

Great to know you are an avid skier, if I run in to issues it will be good to know there is someone out there to help me out on both sides.

James Long
01-28-2010, 04:32 PM
Moooools said...
That is a very wise thought. Although no boat houses around us, just beaches and water. So it should work jus fine.
And yeah we are all pretty fine behind the controls but it would just help us out in the sub perfect conditions we are used to. Or if we stick an inexperienced driver behind the wheel.

Great to know you are an avid skier, if I run in to issues it will be good to know there is someone out there to help me out on both sides.


Well....I have seen people start off standing on skiis in the break water.......but you wouldn't want any slack there really. It is also a dangerous maneuver. If you fall in those first few feet.....you are going to have sand burn.

I would say "was an avid skier". I don't ski any more (not on water any way). My back just can't handle it. I'm usually the one in the boat with the throttle.

I think you have a good idea for the path you will take. You will have to let us all know where you need help.

I think you have probably covered all the bases otherwise. You'll do fine.....but there there can be a bunch to learn if you haven't done much "tinkering" with micro-controllers.

Enjoy the adventure.....

James L

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
James L
Partner/Designer
Lil Brother SMT Assembly Services (http://www.lil-brother.com)

Are you addicted to technology or Micro-controllers..... then checkout the forums at Savage Circuits (http://www.savagecircuits.com). Learn to build your own Gizmos!

Post Edited (James Long) : 1/28/2010 8:37:44 AM GMT