I've been sketching a device to steer and control a solar electric boat, but as I have no experience of building electronics or writing code, I don't know how to proceed..
I have several ideas about what I´d like this thing to perform.
Primarily I'd have Arduino controlling a linear motor for turning motors. Some means of monitoring the angle. 2 pwm signals for the motorcontrollers (signal would have be transformed somehow in to a voltage as its usually controlled by a pot (10k)
these signals would be generated digitally as my ultimate goal is to have android (via BT) telling arduino what to do..
Arduino would have joystick, few buttons and a small display.
Secondary things would be monitoring, displaying and prehaps logging data from few sensors ( Battery state, motor currents, solar panels current, charge/discharge current, Compass heading, temperatures, wind...whatnot)
So my question is what would be the platform to start building this on? I haven't yet grasped what are the limits for arduino or how much resources would this project require..
Any Arduino can control a small electric boat, given the appropriate motor drivers, but some coding skills will be required. I suggest to start by buying an Arduino, downloading the free development system and experimenting with a bunch of the examples provided.
Controlling the speed of a motor will most likely require PWM, which you can learn about by controlling the brightness of an LED.
As for the boat, a used RC model could be a good place to start.
Hi,
the boat is a catamaran, 7 meters ~1ton, solarpowered. Aguess ill just dive in and see how far i get..first thing I need is a digital potentiometer, I see there is a huge variety of these available..all I know is it needs to ned 10K, and replace an analog one in the circuit..and ofcourse be compatible with arduino, any tips?
ave1miha:
I've been sketching a device to steer and control a solar electric boat,
You need to provide a lot more information about what you are trying to achieve. Initially I thought it was a model boat, but now it seems to be full size.
Will you be on board ?
Are you trying to make an auto-pilot or simply remote-control rudder control - which would be much easier.
If you are trying to make an autopilot
what do you want it to acheive?
what inputs will be available to it?
In either casehave you identified a suitable actuator that will have the power to move the rudder and which can be controlled with an Arduino?
Will it be sailing in freshwater or saltwater - which is much more damaging to delicate equipment.
WHAT circuit ?
How do you know it's a pot? Do you have the schematic? Why didn't you post it?
How do you expext us to help if you give us NOTHING ?
How about providing enough information to answer your question
So far all we have is "big" "boat"and "water"
That's not much to go on. How about filling in the blanks , ok
@Robin2,
"Are you going to be on board ? "
Seriously?
I take it you have never been sailing.
Currently , there is no such thing as an autonomous robotic sailboat.
Watch the "Americas Cup" races. It takes a lot of work kn the rigging to keep a sailboat going. Not enough tack and you don't have any thrust. Too much tack and you capsize. You can't go frompoint A to point B like a powered boat. You have to zig-zag from A to B . Then you have to decide how far to zig and zag. Too much zig-zagging and you waste time. Not enough zig-zagging and you waste time. Your angle to the wind needs to 45 degrees. The less zig-zagging the better. Anyone can sail slowly and inefficiently. The trick is doing it fast and efficiently which means maximum tack which = maximum risk.
Where can I get some of the good stuff you are smoking ?
If I told you , I would probably have to kill you...
YOU thought he might have a model boat (which he would NOT be on board)
boat ? (model or full size ?)
dimensions ?
weight ?
powered or sail ?
You got me. I completely missed the boat !
I saw this ...
the boat is a catamaran, 7 meters ~1ton,
and somehow (it was very late and I guess I wasn't paying attention) I missed
this:
solarpowered.
I do remember seeing it but it didn't seem to register. Maybe I thought the solar power was to power the electronics of the sailboat. I don't know but I missed it.
I built, owned and lived on a 35' sailing catamaran - with an autopilot.
Well congratulations on that. I could never build a boat. That's a hell of a lot of work. I did sail my father's 44 foot Hardin sloop a couple of times, and he had GPS and autopilot too but I think you know that all the autopilot does is steer the boat. If all there was to sailing was steering the boat, anyone could do it. As it stands, sailing is a demanding sport. If you have a jib in the front , a stay sail, a main sail and maybe a fore sail, each of those require an optimum angle to the wind. Plus , last time I checked, autopilots don't zig-zag, so that's not going to work. The autopilot is there for motor-powered use, not sailing. I don't know what would happen if you set all the sail booms to a fixed maximum angle (by wenching it to a certain position and leaving it there with a set length of rope) and then just stood at the helm and did nothing but zig-zag (and duck at just the right time ! ). I guess theoretically you could sail that way but it certainly wouldn't be very efficient.
What are the motors and what size are the batteries?
Amazingly those of the least concern to the OP at the moment.
This is all we know at the moment:
first thing I need is a digital potentiometer, I see there is a huge variety of these available..all I know is it needs to ned 10K, and replace an analog one in the circuit..and ofcourse be compatible with arduino, any tips?
No schematic.
Have no idea what this means:
it needs to ned 10K
"ned" is not in my vocabulary
How the OP came to this conclusion is unknown:
replace an analog one in the circuit
any tips?
Yeah, give us more information about the circuit you want to modify. The rest seems to be irrelevant for the time being. Post a schematic or a photo of the pot and post the voltage measurement across the pot as requested. Short of that, no tips.
It has nothing to do with racing. You can't go directly into the wind or directly with the wind. You have to be 45 degrees off from the direction of the wind and if you didn't zig-zag you would not be able to stay on course. If by some stroke of luck the wind was from exactly 45 degrees off from your course
you could just go straight from point A to point B without any zig-zag. If the wind was coming directly from your target landmark (straight at you) you would have to zig-zag to stay on course. If , on the other hand , you are implying that if you decide to go sailing you have no course other than to drive 45 degrees from the wind then of course I can't argue that.
raschemmel:
You can't go directly into the wind or directly with the wind. You have to be 45 degrees off from the direction of the wind
That was not my experience. There were about 90deg centred on the wind direction which were unusable. The other 270deg were usable apart from a very small angle directly downwind. Running downwind requires care and a preventer to avoid a crash-gybe and I would not trust that to an autopilot.
Being lazy I generally chose a course with the minimum requirement for tacking. If the wind is from the North and you want to go North wait until tomorrow.
A sailboat cannot make headway by sailing directly into the wind (see "Discussion," below), so the point of sail into the wind is called "close hauled", and is 22° to the apparent wind.
Ok, I was off by 23 degrees but I was correct about the above.
PS- A year who ever would have thought we would wind up arguing about sailing ?
Ok you lost me My comment was in reference to the 22 degrees mentioned in the link I posted. Are you saying that's wrong ? ( or that it only appies to big expensive racing yaughts yachts)
What do you suppose happened to the OP ? ( kidnapped by pirates ?)
He never answered my question about the pot. He wanted to pilot the boat with a joystick driven linear actuaor (not linear motor because that's a completely different technology based on a flat magnet) ( see his initial post for details). He said hd needed two PWM signals but never mentioned if he was talking about driving the actuator or the propeller or both. Maybe his funding got cancelled after I blew his cover.
@OP,
How much electronics experience do you have?
What is it you want from us ?
( is there a question in all this?)
raschemmel:
( or that it only appies to big expensive racing yaughts)
I don't know about big, but "racing" is certainly true which also probably means expensive. But experienced crew is also required. I couldn't do it on any yacht.
I don't know anything about that. My father gave all the orders and I just followed them. I ussually tried to steer for maximum tack until my father starting yelling that we were off course. ha ha ha
). I guess theoretically you could sail that way but it certainly wouldn't be very efficient.