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Ultrasonic Sensor testing...

Discussion in 'Inspire 1 Discussion' started by Wormwood, Mar 9, 2015.

  1. Wormwood

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    Out of curiousity, I'd like to know if the ultrasonic sensors maybe contributing to the accidents On this forum. One circumstance that's more consistent than others regarding these crashes is a loss of control while relatively close to the ground. So combine this with the ultrasonic ambient noise from pest deterrents, automotive backup sensors & blindspot sensors, garage door sensors, some residential motion lighting & garage parking sensors, I believe there's enough floor noise & the ability for automated systems to generate high levels of noise instantly without warning could confuse the inspire...

    I've done a little research but have found 0, could anyone who read anything similar please post a link?

    Thanks,
    Wormwood
     
  2. Kilrah

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    The ultrasonic sensor would only be affecting height control, has nothing to do with horizontal placement.
     
  3. Wormwood

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    Then why does it have two sensors? I thought this was used with IMU's to maintain attitude?
     
  4. damoncooper

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    Optical and ultrasonic
     
  5. blade strike

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    Yep, ones for position hold and the other is for height.
     
  6. Wormwood

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    Au contraire mon frere... There's two ultrasonic sensors & one visual, so what's the purpose of having two ultrasonic sensors? I can't believe DJI would spend the effort on redundancy for that & not something else...

    Wormwood
     
  7. blade strike

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    Ones an emitter and the other side is the receiver.
     
  8. Wormwood

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    Bladestrike is it at all possible that automotive backup sensors or ultrasonic pest deterrents confuse the Inspire enough to cause an unstable situation? 40kHz range is extremely common for all ultrasonic devices, but how much weight does the Inspire put on the ultrasonic sensor readings for control?

    Thanks,
    Wormwood
     
  9. blade strike

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    I wouldn't think so.. these devices don't have that great of range. 10' under optimal conditions.
     
  10. qbizzy

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    The sensors are a great feature. I filmed inside an empty parking garage. The Inspire kept the same distance from the ground even while we went up a ramp. The same occurred when we descended down the ramp on another shoot.
     
    lrwskyfilms likes this.
  11. Merko

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    What happens if you fly through a large window? When you are passing the window, it will just raise up a lot, and possibly crash in the windowframe?

    I don't plan to do that, but would be nice to know how it behaves, if people plan to film through objects :)
     
  12. The Editor

    The Editor Moderator
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    I do not believe the ultrasonics are an issue in any of these sudden sideways movements upon landing scenarios - It is only there to bounce and listen for 40kHz return path for low altitude calculations using doppler , However........ the thought did occur to me that dependent on how much priority the Inspire puts on the optical tracking via the down facing camera there could be some situations where the Inspire thinks it is drifting but isn't.
    I'm thinking shadow edge of fast moving clouds or maybe even some leaves etc which are blown sideways by the prop wash during decent.
    If the algorithms are written such that once the craft has a 'lock' on the ground pattern it puts more emphasis on the optical tracking than on the gyros/accelerometers, if that ground pattern suddenly moves sideways (leaf blowing etc) the Inspire can only assume it has drifted in relation to it's world (again, I am making assumptions here that there is a priority hand-off to the Optical flow at very low altitude)....

    Just an hypothesis......

    Personally, I would like to see the option in the app to turn the optical flow completely off if the user has no use for it in a given situation,