Photomapping Camera Stabilization using Silicon Gel

I am new to this site within about the last month, trying to get up to speed for aerial mapping using a UAV, currently using ArdupilotMega with a skywalker for vertical mapping. In mounting a small camera inside the fuselage of the Skywalker, I experimented with silicon gel for vibration isolation, which appears to be promising. The current testing used a Canon SD1200 IS camera because it was available, but I would plan on using something with a larger imaging sensor in the future (http://www.rcgroups.com/forums/showthread.php?t=1351104).


The test flight in the video above used the SD1200 in video mode in order to collect a continuous record of vibration and performance, stabilization was turned off for the flight.

 

I am now starting on roll stabilization using Alpo's code technique. I also need to solve camera triggering, hoping that an IR trigger solution will work. Since I may move to a Sony Nex-5, I need a non CHDK canon option for triggering.
The silicon gel approach looks very effective so far, in the future I will order some gel tape with adhesive backing for a more integrated solution and to adhere the camera to the mount, somewhat like double sided foam tape, except gel. The gel is very effective for high frequency vibration if the surface area used is matched well with the weight of the object. Their may be issues with lower frequency vibration, but that is likely the case with almost any design. Any suggestions, advice, and observations are appreciated.

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Comment by Steve on June 9, 2011 at 10:25am
Comment by Ritchie on June 9, 2011 at 12:40pm
There are plenty of tutorials on doing Canon IR control I have done it with a ProMini two outputs and an old remote IR LED. Could easily be done with an ATTiny85 and you could then call it instead of tieing up the flight control loop.

Developer
Comment by John Arne Birkeland on June 9, 2011 at 2:47pm
It could just be the recording, but it sounds like you have some vibrations in your motor. Have you spent some time making sure the propeller is "perfectly" balanced and looked over the motor? The reason I ask is because the Skywalker foam acts like one big vibration dampener in itself. And I get good results without adding extra dampening beside the velcro I use to fasten the camera (and some rubber bands to make sure it stays pressed against the velcro).
Comment by Philippe Petit on June 9, 2011 at 2:56pm

Another method for triggering a sd1200 camera is the CHDK. With this tool you could trigger the camera via USB using the relay of the APM. For the CHDK (Canon Hack development kit, sound more bad ass then it is) check http://chdk.wikia.com/wiki/SD1200IS . This is actually critical, as you need a certain firmware version of the camera, but maybe you are lucky.

Triggering via usb would have to be performed with a skript which can be run via CHDK , the guys at mikrokopter.de did something similar (here is the link, but unfortunately its on german http://www.mikrokopter.de/ucwiki/CHDK).

To trigger via usb, you would have to use the relay switch, (after some soldering on the usb cable to the appropriate port on the APM board). The necessary arduino code for steering the relay can be found in the documentation of APM ( http://code.google.com/p/ardupilot-mega/wiki/Relay ).

Perhaps you find it useful. Good luck and have fun

Comment by Cliff Gill on June 9, 2011 at 2:59pm

Steve, I saw some mentions of Moon gel, that does look about the same. I did receive some adhesive backed material from vibrationmounts.com and it looks slightly slightly stiffer, but the adhesive backing may be helpful over both the toy silicon and the moon gel.

Ritchie, thanks for the suggestions, I'm hoping to find something very simple and almost plug and play? I was thinking of triggering the camera with a gentles trigger (http://www.gentles.ltd.uk/gentled/shutter-zoom.htm) . These commercial IR triggers appear to often be configured for a single make of camera? I can't use the same one for Canon and for Sony, (anyone tried this?). Gentles indicates that one can use both an RC receiver to release the IR, or it can be triggered simply by shorting one of the wires to ground. It would be convenient not to tie up one of the extra Servo channels on the APM (save them for pan, tilt and yaw on a camera).  In the short term I could use one of the extra servo channels on the APM directly with the gentles IR trigger, and later then go with your approach when I needed pan, tilt, and yaw? Ideally I would like to program all of the photo trigger locations into the flightplan as camera trigger waypoints, rather than making the camera shoot continuously, or doing it manually, is this typical? Does your new camera control software release make this fairly straightforward?

Comment by Cliff Gill on June 9, 2011 at 3:14pm

John, Thanks very much for the observations. I have not balanced the prop yet, partly to see how the gel method works under non-ideal conditions. But I am going to balance the prop as you suggest and see if it quiets.

Philippe. My long term plan is to use a Sony Nex-5 (or other very compact APS-C format camera, canons don't offer this yet) which would rule out the CHDK option, I believe? However, for the short term, your USB via CHDK and the relay switch might be my best option. Also, the relay switch would be an obvious answer to shorting the gentles IR trigger without using an APM servo channel. thanks.

Comment by Philippe Petit on June 9, 2011 at 3:57pm

yes, the chdk is only available for a very small collection of canon compact cameras. However, ir-operation of the camera sound good. Another Idea would be to short wire the trigger somehow. But maybe ive never seen this kind of modification for a reason.

How are you intenting to tile and pan the camera? Have you found someone who coded this already in APM? I saw some videos (and figured it couldn t be so hard as you already have the necessary pan and tilt angles.) But i never saw someone who documented it in the Forum. That is why i ask.

Comment by Cliff Gill on June 9, 2011 at 6:18pm
Philippe, I may only roll stabilise, as so far I am fitting the entire gimbal within the skywalker airframe, and more gimbal axis will take up much more space. I am only familiar with two options for camera orientation control: Ritchie's (http://diydrones.com/profiles/blog/show?id=705844%3ABlogPost%3A3725...) and Alpo's (http://diydrones.com/profiles/blogs/easy-camera-roll-stabilizer-to). My triggering plan currently will be to use the integrated relay to short the Gentles IR trigger device, this should allow me to use any camera that the gentles is compatible with.

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