Open Source Boat Controller Project

Discussion in 'OnBoard Electronics & Controls' started by MurphyLaw, Aug 7, 2018.

  1. MurphyLaw
    Joined: Aug 2012
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    MurphyLaw Senior Member

    And then their idea of open source is a lot different from mine, you take a $20 chip and add on a $5 chip and the total is $150 ??? There are so many "open source"projects out there that rely on your purchasing their $150 >$300 board which is in fact a $20 board.

    I counted more than a dozen of these on one page alone.

    reg.jpg

    Registered this registered that, like wtf, learn open source.
     
    Last edited: Aug 22, 2018
  2. MurphyLaw
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    MurphyLaw Senior Member

  3. BMcF
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    BMcF Senior Member

    Very impressive progress. I'm following your laser range-finding research/testing with a keen interest.
     
  4. MurphyLaw
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    MurphyLaw Senior Member

    This is the cheapest entertainment in town that's for sure. A car wind shield motor, a ladder and a pool. It's hypnotic and very cool.

    I was really doubtful whether the motor would have enough torque to drag a foil around, was sure the motor would overheat quickly, if it could manage at all.
    But the motor did not even get noticeably warm after running for 5 minutes and it recorded a speed of 0.55 revolutions per second on standard speed. Which is 12kts, perfect speed as if you are not foiling properly at 12kts, you will battle to get much faster using your hulls in all but the strongest winds.

    It also bears out the principles of flight, that you can fly a barn door if the rest of the package is right. I was trying to find out the maximum foil size the motor could drag around but the piece of aluminium plate would keep flying out of the water.

    No need to waste stupid amounts of time trying to create the perfect foil shape, what is more important is the complete package, then when I have that right I can look at foil shapes.

    I need to get some 3mm threaded bar and other goodies and now I can move onto creating my first foiling craft.
    testing.jpg
     
    Last edited: Aug 26, 2018
  5. MurphyLaw
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    MurphyLaw Senior Member

    I can see from this already that the camera and laser need to be mounted in front of the foil as the rooster thrown up from the keel slicing through the water will interfere. But I have a bullet proof design to measure the height above water regardless of spray but it needs to be built into the keel.
     
    Doug Lord likes this.
  6. Doug Lord
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    Doug Lord Flight Ready

    Sounds good!
     
  7. MurphyLaw
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    MurphyLaw Senior Member

    Here's an updated connection diagram. I am still under $100 for all the equipment so far.

    The Raspberry Pi Infra-red camera is about $30 **you need to get a different cable to the one supplied with the camera to fit the Pi-Zero***

    The Raspberry Pi Zero is about $15
    The Uno is about $15
    The servo is $10
    The laser range finder is $ 15
    The ultrasound is about $15
    The BNO 9 axis sensor $15
    A wind shield motor should be less than $25. If you can't get one for free from an auto breakers yard you need to work on your people skills. They are never going to get more than scrap metal value for it.
    A ladder. You must live in a **** hole if you don't already own one;)
    The aluminium pole is an old TV antenna pole, scrap metal dealer $1

    You don't even need a swimming pool to do this, the test rig is just a ladder that you can put on the roof of your vehicle, if you rig up supports like fishing rod holder spikes, that you could just push into the bottom of the lake/sea/river bed, 12mm reinforcing bar for concrete will work great. easy enough to bend in a vice to make loops for the ladder legs to sit it, then you could support it over any lake,river,pool
    latest-circuit-diagram.jpg
     
    Last edited: Aug 27, 2018
  8. BlueBell
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    Location: Victoria BC Canada

    BlueBell Ahhhhh...

    Ahhh, a pressure sensor...
     
  9. MurphyLaw
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    MurphyLaw Senior Member

    On the Rasberry Pi you need to type

    raspi-config

    Then you need to enable the following;

    Camera
    SSL
    Serial port.

    Then setup the Pi for remote login via WiFi. (Download a tutorial or wait until I produce an image later where you will have to do nothing.)

    Then you need to download a program called "Solar Putty for windows"

    Then you logon via Wifi to your Pi.

    You then modify a file caller rc.local in your /etc directory by typing

    nano /etc/rc.local

    and add this code just before the exit 0 at the very bottom of the file.
    Code:
    stty -F /dev/ttyACM0* 115200 raw -clocal -echo
    cat /dev/ttyACM0 > /root/mylog.txt
    This code will make all the data from the Arduino go to a file called mylog.txt on the Pi. Reboot the Pi and from then onwards, any data from the Arduino will be in that file. When you power the system up it will do this automatically, then you can logon whenever you want to via wifi to pick the data up, or observe it real time.

    Now all you do is logon via Wifi to the Pi and all the data will be in a file called mylog.txt

    I am going to overlay the data onto the video later this week so you will have a video with the data in text displayed.
     
    Last edited: Aug 26, 2018
  10. MurphyLaw
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    MurphyLaw Senior Member

    No I will create a baffle like on a car exhaust, one cylinder full of holes, the laser or ultrasound shines down this cylinder, the aim is to make the holes small enough to stop any spray from getting into the cylinder but not so small that the cylinder does not change its level of water quick enough in response to outside changes in level. You just have a bunch of holes on the side of the keel the rest of the cylinder inside the keel.

    Tested physics, if the spray is bad enough then you use another cylinder on the outside with holes in it, baffling technology, that is the problem, how to suppress spikes in level, aka spray, with the same technology an exhaust suppresses spikes in pressure.

    It will work, the key will be using enough baffles and the hole sizes to suit the application.

    Venturi effects are significant when the size of the hole is small compared to the surface it is on,when the surface is full of holes, so the hole size is larger than the surface it is on, then they become insignificant.....I think.... that is my ****-to-remember about the venturi effect.
     
    Last edited: Aug 26, 2018
  11. MurphyLaw
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    MurphyLaw Senior Member

    I am going to hinge the foil at the very front, so if the foil control fails then the foil will go to the position of least drag from the forces of nature, that will be important, the foil must return to the position of least drag if anything goes amiss. This will mean that any craft will just start to drop off from foiling and will not pitch pole violently forward. When I start investigating foil shapes I will place the pivot just in front of the centre of effort of the foil.
    hinge1.jpg
     
  12. BMcF
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    BMcF Senior Member

    We used pressure sensors to sense depth and control bow height on SWATH systems way back in the day. Total PITA...very sketchy and unreliable due to fouling issues mainly. Not as big an issue for a recreational craft that lives on a trailer though...so there is that.
     
  13. MurphyLaw
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    MurphyLaw Senior Member

    A baffled sensor would be unlikely to have all the holes blocked and you could pick that up in software, the sensitivity would drop off. Strong laser is probably the best but you are going to battle with commercial approval because any laser strong enough to cut through spray is going to damage the eyes of anyone looking into it. But I think you can do it with camera alone because of the colour of the spray under infra-red light, teach the software to recognise spray, the same way a human watching a video could tell what was spray. The best autonomous vehicles use a multitude of sensors which gives you the advantage of fault recognition and redundancy which is my preferred method.
     
  14. BlueBell
    Joined: May 2017
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    Location: Victoria BC Canada

    BlueBell Ahhhhh...

    Thanks Murph.

    I know what you've described as a "still-well".
    They are used to measure tsunamis, very small ones.
     
    Last edited: Aug 27, 2018

  15. MurphyLaw
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    MurphyLaw Senior Member

    Yep you have to be born in Victorian times to come up with anything new in engineering, like user names, DaftOldMan345.....name already taken, hahaha
     
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