PC Autopilot program

[bendyone]

Any ideas how a laptop can be used to control a drive for a autopilot? Imput from a fluxgate compass / maybe wind inst. and a simple output to drive the motor.
Are there any programs out there?

 

[ShaunG]

Are you looking to use the PC to do the job of the autopilot computer. I like the idea, i use a PC for most of my Nav and have all the data on the network.

I can see a problem with providing the motor with power, i guess the were need to be a USB? powered board that has mosfets to power the motor.

I don't know of anything, if you find something then please let me know

ShaunG

 

[bendyone]

Thats the plan if it is possible, I guess for the motor drive if a couple of relays could be controlled via a USB port that would do the job.
Must be possible by how??

 

[ShaunG]

Someone has almost managed it

this site looks like a starting point, someone managed to do smoething similar a few years ago, looks as though an update may be needed http://home.combitel.no/gpsii/AutoPilot/

 

[snowleopard]

You build the hardware, I'll write the software. It wouldn't be hard to improve on Raymarine's offerings!

Split the profits.

 

[ShaunG]

I am now quite taken with this idea.

I am sure between us Forumites we have the skills to create something, as far as i can see we need the following:

1.PC based app to carry out the function of the course computer

2.interface device between computer and drive unit

3. Feed to PC with all NMEA data including fluxgate, Gyro if reqd, speed, heel angle if available, rudder position (anyone seen a NMEA rudder position sensor) wind etc.

4. Waterproof input device to change heading and enable/disable autopilot

I have number 3 in place already, i.e PC with all instruments using NMEA into a dedicated 12v PC. just missing the NMEA rudder position, i will look into sourcing one

I reckon that something like number 4 must already exisit.

I reckon there's a chance that number 2 may exisit.

i reckon i am screwed on number 1 - over to you snowleopard.

Anybody fancy a go at this?

 

[ShaunG]

Looks like number 2 could be done with these

http://www.controlanything.com/Relay/Relay/CAT_RELAY1

not USB but my poor understanding is that RS232 data is easier to write and output.

More than happy to purchase if peeps are interested

 

[Anthony]

there are lots of PIC chips that can interface to USB easily, in fact there are development boards that have USB interfaces on them with example VB drivers etc. personally I would go the USB / PIC route. This could also serve as item 4, with teh addition of a few waterproof switches. Actually come to that you could do the whole thing with a PIC but thats a different thread...

Ants

 

[ShaunG]

NMEA Rudder Sensor Sorted

Looks like there should be no problems with obtainin rudder position on a NMEA bus.

there are a couple of people doing NMEA Rudder sensor things

http://www.tinleyelectronics.com/products.htm

http://www.cruzpro.com/am30.html

i am sure with a bit more searching i could come up with a black box solution that is well priced an neat.

is there some money to be made here? components are not looking expensive but obvioulsy the knowledge and develpoment would cost loads (forumites)

can a better autopilot be built for less than a ray[word removed][word removed][word removed][word removed] - looking likley in my eyes

 

[Anthony]

I have no doubt that between a group of people on here we could get a hardware / software combination that works. The question is how many people have or want to rely on a PC for their autohelm (espically on a yacht where power is at a premium), and also it may take quite a bit of tweaking to get the algorythm correct so that it responds and predicts the correct amount of correction allowing for various hull designs, speeds and sea conditions etc; but feasbile yes!

Ants

 

[ShaunG]

as per ants reply there appears to be loads of options for controlling the software running on the PC with an input device, PICS seeming to be the most popular.

these people have some smart looking devices that don't appear to need to much work and seem to have the PIC and USB interface already there

http://www.matrixorbital.com/product_info.php?pName=glt240128gw

 

[ShaunG]

I agree with the PC problems.

i have been running one now for about 3 years and have had less problems with it than my raymarine autopilot.

However i think we are probably a few years away from PC's as we use them now becoming popular on small boats.

Superyachts and the like seem to use glassbridge PC based solutions at the moment and i can only see the use of the technology filtering down. Raymarine have tried it with the G series, which appears to be a PC running linux and Simrad are doing it with their glassbridge system. I think the 2 systems from major manafacturers have not taken off of the basis of cost.

Could we be there ahead of everyone else?

 

[wotayottie]

Most people using a PC will already have a set of instruments on board which will have an NMEA bus. The Cmap lappy program that many long distance types have (Cmap 93) has the capability of outputting the NMEA autopilot sentence though I doubt that it has the algorithms for sailing boats that a good autopilot has. Probably just a simple steer to a waypoint with built in adjustments for drift / leeway etc. So the bits that are missing are the ones which take that NMEA sentence and turn it into volts and amps for the drive motor.

In reality thats what most autopilot computers do.

 

[ShaunG]

good point wottayottie. i have seapro and it has autopilot output as well.

However, i think this is a APA/APB NMEA sentance that can send requests to a Course Computer. In this case some software would still be needed to change those requests.

On second look i might have just said the same as you. Are we therefore saying that if you already have a PC with some software that can output APA/APB and interface it to the drive. If this is the case then what do course computers do when interfaced to a PC based plotter?

I think a software app may still be needed to control response/ sea state etc

 

[skenn_ie]

SOB

I have SOB from Digiboat, a Plotter program that can accept and send data from/to most nav hardware. I don't know the details of it's use to drive the steering, but there are loads of devices to control motors with PC's. Have a look fat geckodrive.com. They are a family of PC - Motor interfaces

 

[bendyone]

Seaclear can output APA/APB NMEA as well as other things.
I like the way this is going, it seamed such a simple idea to me I'm surprised that someone has not already done it, hence my question.
I would need it to drive a hydraulic pump in the steering system. I'm up for testing it if someone can do the cleaver bits

 

[nimbusgb]

this any good?

http://www.trossenrobotics.com/store/p/5389-10A-Dual-H-Bridge-Controller-Board.aspx

2 channels allows forward reverse control

 

[bendyone]

Compass
http://www.trossenrobotics.com/sparkfun-compass-module-with-tilt-compensation.aspx

The bits are out there but what about the main software.

 

[nimbusgb]

I have source code for a PID controller loop if anyone is looking to actuully build software from scratch.

 

[bendyone]

My boat has not got a autopilot but has hydraulic steering so if I fitted a pump to the steering system (so I could also use a outside joystick to steer) I need something to control the pump. A usb controlled reversing relay.
I use Seaclear so if I could find a device to take the Nema APB message from seaclear and decode and convert it to a left / right signal that would do the basic job for starters. Some form of sensitivity would need to be added.