SparkFun Forums

[No1Daemon]

Hi all

A while ago I posted several posts all over the net to get some assistance in writing an Arduino sketch to control a steering rudder of a Kontiki fishing vessel via GPS and/or Magnetometer.
Post links are
http://www.google.co.nz/url?sa=t&rct=j& ... 4169,d.dGY
http://www.google.co.nz/url?sa=t&rct=j& ... 4169,d.dGY
http://www.google.co.nz/url?sa=t&rct=j& ... 4169,d.dGY
http://www.google.co.nz/url?sa=t&rct=j& ... 4169,d.dGY
And I am sure there is another I forgot.
The Kontiki is a semi submerged torpedo that travels on the surface powered by a trolling motor and has the fishing line attached to the back, usually off centre so the tension of the line holds it on a reasonably straight course out to sea.
I have one fully home built and also have programmed a timer that can be set in increments of 5 minutes and is activated with a magnetic reed switch. After the timer expires the motor stops and a weight hitched near the back of the kontiki sinks to the bottom so your line which usually has approx 20-30 hooks on traces attached lies on the bottom.
The line is on a large reel on the beach and after waiting an appropriate amount of time for the fish to take the bait you reel in the line, dragging the kontiki back to shore and start filleting(hopefully)

I have long wanted to include some sort of control to make the kontiki go in a straight line instead of leaving it to tension/waves/currents.
The logic goes like so
Point Kontiki towards target
Press button/activate reed switch to set bearing
Place in water
Kontiki controls a steering rudder according to the bearing to go straight ahead as per direction it was pointed
Timer stops motor

Should be fairly simple for some of you. I am a novice still when it comes to Arduino but I have managed to make a working GPS model using a Microsoft streets GPS unit and get nmea data back etc
I have also managed to make a 3 axis magnetometer following a few tutorials on line that seemed to work, needed a little calibrating but seemed pretty accurate.

So I would like someone with a bit of technical knowledge and Arduino no how to hold my hand and assist me to put it all together.

Or if anyone can suggest a better alternative I am open to suggestions.

Commercial units are available but are expensive so I want to program my own plus it will be far more satisfying and fun and teach me a lot about programming etc.

To see the commercial units please look at the following links
http://www.google.co.nz/url?sa=t&rct=j& ... 4169,d.dGY
http://www.google.co.nz/url?sa=t&rct=j& ... 4169,d.dGY
http://www.google.co.nz/url?sa=t&rct=j& ... 4169,d.dGY
Any help would be greatly appreciated
Steve

[fll-freak]

You first need to decide between a GPS and an magnetometer solution. Both have pros and cons. The big difference is that a GPS does not give you a heading unless you are moving at a reasonable clip. But GPS could get you to an exact point regardless of cross currents. A magnetometer solution would be great for heading hold, but would be subject to the magnetic interference of your electric motor as well as cross currents.

Once this is decided the algorithm can be designed and implemented.

[No1Daemon]

My apologies for the late reply, I never got notification a post had been made.
I have decided on a compass one and found a post on this site which has all the neccessary code.
I just need to creaste a timer and I am good to go.

Thanks for the reply.