Favouring upwind slow flight for taking pictures

Posted by Drone-University.com on March 23, 2014 at 12:33pm

Before doing that, I would like to have your opinion.

I have always tried as much as I can to take advantage of nature forces instead of fighting it.

So I am starting from a fact : upwind flights are way slower than flying downwind.

I want to take advantage of that fact for taking pictures of my subject of interest ONLY when flying upwind.

That way, I could

a) fly much closer to the ground for more details and

b) even when taking 1 pic every 3 seconds,still having plenty of overlap.

1- Does that make sense or is it completely silly ?

2- If possible, I would love to limit the pictures to upwind flights. Do you know any way of doing that ?

That would mean only taking pictures between specific waypoints instead of every time I fly a distance of X. 

3691107268?profile=original

Thank you

upwind.jpg

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Replies

  • Eli Cohen March 23, 2014 at 7:34pm

    very sensible! upwind vs downwind makes a huge difference in pixel blurring through a relationship that is a function of focal length, aperture, sensor size, altitude, and ground speed. You can calculate it all out, I would be happy to share some code I have written to analyze different cameras.

  • iskess March 23, 2014 at 2:29pm
    Just use the command do_set_cam_trigg_dist. Set it to zero when starting a downwind leg and set it to your desired trigger distance when flying upwind.
    • Drone-University.com > iskess March 23, 2014 at 3:06pm

      Geat one, thank you !   :-)

    • Drone-University.com > Drone-University.com March 24, 2014 at 12:04am

      So basically mission would look like that one (simply given as an example)

      1- Before the flight, do_set_cam_trigg_dist is set to 0 ;

      2- Just before strategic waypoints 6, 12 and 18, do_set_cam_trigg_dist is set to 15 meters ;

      3- When the waypoints 7, 13 and 19 are passed through, do_set_cam_trigg_dist is set back to zero.

      waypoints.jpg

    • iskess > Drone-University.com March 24, 2014 at 12:15am

      That is exactly what I meant.

    • Drone-University.com > iskess March 24, 2014 at 12:23am

      Thanks a bunch Iskess !

    • 300km
      moglos > Drone-University.com March 23, 2014 at 9:06pm

      Another option (and I think much easier) would be to have a switch on your RC, hit the switch to start taking pictures, and then hit it again at the end of the upwind leg to stop. A switch would save you from having to dig into the APM settings and keep making changes, and writing them twice each lap.

      I use a gentwire USB trigger with a canon camera and CHDK, but it would work for most triggering systems, even the good old servo on the shutter button.

      One risk though (and I think it's a risk with the do_set_cam_trigg_dist method too) is that you can forget to turn the shutter trigger back on. I've turned it off when I was flying over a non-interesting area (I was worried about the battery) but I forgot to turn it back on. It seems like a pretty basic mistake, but when you're flying and checking your height, speed, rssi, battery, flight path etc it is easy to forget. For that reason I'd recommend just leaving it on the whole time if you can.

      From my experience the risk of distance triggering not working is greater. I really like the idea of it but it is hard to check that the camera and CHDK script is setup setup properly. I test it by setting do_set_cam_trigg_dist to 1 and listening for the shutter (it should go off reasonably often even if you're standing still). Then I change it back to whatever I need for the flight. But despite doing that I've had flights were I didn't get any images except for the test ones on the ground.  Any suggestions there much appreciated because distance triggering would be really useful.

      Because I'm using USB for the trigger, I can't get live video out of the camera, if that was possible I could use a FPV link to check that the camera is working during the flight. A workaround I've been thinking of would be to have a FPV camera pointing at the camera screen.

      Anyone got any better ideas for how to check that the camera is actually working in-flight?

    • iskess > moglos March 24, 2014 at 12:20am

      Moglos,

      I think you misunderstand that do_set_cam_trigg_dist is now a command that can be automated (Thank you Tridge!)

      There is no digging into the APM parameters like you fear. And there is no concern with timing your finger on a switch, or concern with loosing RC contact for a little while. Its launch it and watch it do its magic.

      To verify the camera is triggering, I simply tape the FPV microphone to the camera speaker and listen to her shutter make that beautiful music. However its never failed me.

    • 300km
      moglos > iskess March 24, 2014 at 1:27am

      I didn't know that, that's great thanks iskess and Tridge. It will also be handy if I fly a certain area at two different heights, you can change the trigger distance from one pass to the next.

      I thought about listening to the sound of the shutter beep through the FPV, but I thought it would be drowned out by the wind noise. Great to hear that it works, I'll definitely give it a try. Do you have a separate mic?

      Thanks for the great tips, awesome.

      (I set up my failsafe to shooting if RC contact was lost.)

    • Drone-University.com > moglos March 24, 2014 at 3:27am

      Quote

      I set up my failsafe to shooting if RC contact was lost.

      Unquote

      Can you explain furter please

      My failsafe is simply set up to RTL.

This reply was deleted.