Position Hold flights at High Altitude with the OptiFlow Tricopter (OFT) v1

Successful high altitude (>100m AGL) position hold tests flights with an optical flow sensor on a Tricopter (OFT) UAV.
Tests flights:
1) Fast climb rate to about 100 m AGL in hold position mode with only the throttle command.
2) At 100 m AGL, a 360° turn has been done (wind 14 km/h from SE) with only the yaw command.
3) Fast descend from 100 m AGL whith the horizontal stabilisation active.

All the tests flights have been recorded with a GoPro HD Wide video camera

More infos at:

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  • Hi Jean-Louis Naudin,
    Today I tried to do of_loiter but after switching flight mode to OF_LOITER form STABILIZE is simply flying here and there and altitude is increasing in step wise. but if I switch to OF_LOITER with less than 50% throttle then its simply landing. I'm not getting whats the problem. So please help me to sortout this problem.
    Ravi Kishore MV
  • Developer

    I actually bought a flymentor and opened it up to see what was inside and it looks suspiciously like an ADNS2620 (or maybe ADNS2610) mouse sensor!  You will definitely need some part of the controller to know it's altitude because the feedback from the optical flow sensor will become less and less as you get higher.  I.e. at 10m it's feedback will be 10x less than at 1m.  At 100m it will be 100x less.  Eventually you'll get down to the point where the sensor cannot sense any movement or at least it will be unable to distinguish between the horizontal movement and the movement caused by rolling/pitching of the airframe.

  • Developer

    Hello Fouad,

    I have tested a friend flymentor 3D but unfortunatelly I haven't yet succeed to work with it at high altitude.

    Regards, Jean-Louis

  • @Hai,

    Did you ever get flymentor3d to work in high altitude ?

  • Moderator
    Hey Jean, are you going to post that tutorial you mentioned.  I just received my flymentor3d, it was rather cheap so I thought I'd give it a try.  Unfortunately my last crash has me waiting on a new landing gear.
  • Thanks for the prompt response and for cracking this code!
  • Developer

    This is CCD camera with a custom processing.

    I recommend you to look this video:

    Regards, Jean-Louis


  • Can you tell us about the underlying sensor? Is it a AVAGO mouse chip or a CCD with custom processing? Or something else?
  • Developer
    I shall soon post a full tuto about this... stay tuned
  • Moderator
    So what lens did you replace it with (and how), and how did u tune the new lense?
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