Public Lab Research note


String and paperclip method for attaching Mobius camera to dowel pendulum rig

by tonyc | November 30, 2015 22:39 | 1,972 views | 7 comments | #12463 | 1,972 views | 7 comments | #12463 30 Nov 22:39

Read more: unstable.publiclab.org/n/12463


Find a safe, no-cost and teachable method for attaching a Mobius Actioncam to a dowel

The method:

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I started with a double "barrel hitch" knot, with the string ending in two overhand loops.

I took a keychain (could be a paperclip or whatever) and formed it into a horseshoe shape, with slight out-turn at the ends.

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I marked the dowel at approx crossing points, then nicked little slots with a knife.

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Then I put the dowel in place,, and spun the horseshoe to cinch it all down. Then I tucked the end of the horseshoe under the taught line to lock it in place (see main image).

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The whole unit is just a rubber stopper, small-end-up, over the dowel and going into the neck of a 1/2 soda bottle. I left one end of twine long, so it could protrude through the neck, potentially clipping it to a carabiner as a safety should it slip off the dowel for some reason.

Questions and next steps

What do you think? Is this too complicated? Is it actually worse than rubber bands, safety wise?

@pcoyle

I'm hoping to offer a complete kite aerial mapping kit and want to find a way to handle the connection between camera and rig that isn't rubber bands.


7 Comments

This looks excellent.

John Wells in Scotland has been working on pendulums for keychain cameras and settled on a coat hanger. A nice feature is that the top end of the coat hanger becomes the perfect thing to wrap the flying line around. He attaches the camera to the wire with Velcro (some adhesive backed Velcro patches and a Velcro strap should be plenty).

His pendulum is a transverse pendulum in which the lower end of the long shaft holds only a counter weight. The camera is up near the flying line but rigidly connected to the shaft. The counter weight damps swaying, but the camera does not have to experience the entire arc of the swings. A coat hanger would make an effective normal pendulum as well (with the camera at the lower end of the shaft) but I'm not sure the Mobius has enough mass to make a pendulum effective.

A soda bottle could be fit around the camera if desired, but the small mass of the Mobius does not demand much protection. Just a cage to keep the lens out of the dirt should be plenty. A cage could be formed from the end of the coat hanger. So one continuous wire does everything.

Total cost could be under $3 including a lanyard. Clothes hangers of 13 gauge wire are 50¢ apiece.

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More about John Wells' design here: http://www.armadale.org.uk/snaps.htm

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Very cool, Chris! Thanks for the ideas on this.

I still think my method is a bit fussy for public consumption, as it requires some dexterity to get the knots just right. ideally, the method would be simple to use and not hinge on a knot being executed perfectly to keep the think from falling.

I was playing with another idea, using a pair of zip ties, one actually suspending the camera, and the other sliding over to lock it in place.. The tail end can be secured by friction to a dowel, using a bit of tubing. I added a tack to make darn sure.

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Then Chris' point that you really don't need much to protect the mobius other than something to keep the lens out of the dirt made me think I could get rid of the bottle, and just make a tight sleeve to both protect the lens on impact, and keep the main zip tie from sliding out of position and dropping the camera.

And here's the result:

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A sleeve of plastic/vinyl of the right diameter could replace the DIY version in a kit, as long as it fit snugly and could slide on/off without getting too loose over time.

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big problem I can see is the zip tie allows a wobble that would introduce big jello effect and blur in real wind. I liked the dowel because it was more rigid. seems like a hybrid of all these can get us there. I'll keep tinkering

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I love the sleeve! very low profile in the wind, too. Why so against rubber bands?

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Mainly just safety. just looking for something that would be a "positive lock" between the camera and the kite so nothing squirted out, or in case a rubber band broke. It's so easy to nick a rubber band with normal use, and even though I'd totally fly one myself, I'd be afraid of hearing back that something broke or failed on it.

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Kind of dorking out on this, but here the thought is to put a stopper at the end of the dowel, so the camera, under tension from the sleeve, really can't fall out. With a bit of a filing job to let the zip tie end recess a tiny bit, it's really locked on there.

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And here's just an added bonus of protection if you make the sleeve with a couple ties and use the ends to give you crash legs. Sure there's better way to use thicker ties, or longer ties and then tuck them in to each other to give little loops. But the idea is there.

Bonus on this is you can press the buttons through the sleeve, and you can see all the status lights through the clear plastic.

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Tony, looks promising. The info from Chris is great as well. Lots of ways to go. Having committed many cameras secured with orange rubber bands to altitude, I'm less worried about their failure. However, in all these approaches, careful check for tears, loose connection, etc, is needed. Regarding the wobble, could use a couple of pieces of foam to snug the camera against the shroud.

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Committed to Altitude, the Pat Coyle Story, coming soon to a bookstore near you...

My final contribution for the day: I'm happy with how strong you can get a zip tie to lock onto the end of a dowel, and came up with the following, super-easy-to-teach method of getting the camera to lock onto the rig. The method is to cinch the zip tie down on the dowel as tight as you can, then slide it off, go one more click, and then jam the result back onto the dowel. It is on there

I then used the tail to wrap up, and tuck under the loops of the other two ties. The two ties are necessary to keep the camera in alignment, but you can easily slide them off to fuss with the camera. The friction of the ties on one another is just the right amount to let you remove them, but also trust them to stay in place in flight.

Protection for the camera could be added by tucking a couple strips of bottle plastic into the rig, having them protrude forward and away from the lens. Not going to fuss this part today, but consider this the devil-may-care model shown:

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