Public Lab Research note


The BRIT camera rig

by jbest | November 15, 2013 20:17 | 3,646 views | 2 comments | #9785 | 3,646 views | 2 comments | #9785 15 Nov 20:17

Read more: stable.publiclab.org/n/9785


Exploring different camera rig designs

Because I expect to eventually have more hardware than can fit into a 1 liter bottle, I decided to start exploring different ways to suspend and protect a camera. This is my first pendulum prototype that I made after learning that my picavet setup would not work well with a balloon. Eventually I'm going to try similar designs for dual camera surveys and then the addition of a Raspberry Pi (testing wireless control of cameras and access, etc).

My attempt and results

I built a very simple rig made mostly of 3/4 inch flat aluminum stock. The pictures below probably demonstrate the design better than I can describe, but I'll add a few notes about the choices I made. It is a simple cross of two pieces of aluminum with one piece bent down to provide a place to mount the camera and further extensions to protect the lens in case of a fall.

Parts:

3/4 inch aluminum stock
2 - screws and bolts - for attaching aluminum pieces
1 - bolt for camera mount
1 - nut for camera mount
string
fiberglass rod or other thin, light material for the tail
thin, stiff plastic for vane
electric tape or other for attaching vane to tail

Tools

hacksaw
wrench
screwdriver
drill
drill bits
file or Dremel (to de-bur holes so they won't cut string)
vise, clamps, or edge of a table, brick etc to bend aluminum

IMG_2922.JPG
The cross is secured by two screws and bolts. A fiberglass rod passes through the bent piece of aluminum and has a plastic vane attached with electrical tape to reduce spin. The camera is secured with a nut and bolt using the camera mount.

IMG_2924.jpg
The 50 lb kite string loops through the holes on the top of the rig and meet in loops at the top, 30 cm above the rig. They do not slide like a picavet would, the knot at the top holds the rig in a level position below the loops. I added a 2 meter extension to this when I saw that the rig was swinging too much.

IMG_2926.JPG
The long cross and the bent piece of aluminum keep the camera from touching the ground if it falls. I forgot that the camera mount is not centered so when lying on the other side, it barely touches so that should be extended in future builds.

The full rig weighs 80 grams alone and 220 grams with Canon A2400 camera. It worked really well for our purposes. The battery and SD card door is accessible without removing the camera, and all the buttons and screen can be used with the camera in the rig.

Questions and next steps

The only thing I'd change at this point is making sure the cross piece is long enough to protect the camera, but this isn't enough of an issue for me to fix this prototype at this point. You could probably shave off a lot of weight by using thinner aluminum stock, but I just used what I had on hand. Future iterations will accommodate dual cameras and other gear, but this one is a keeper for single camera use.


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2 Comments

That's a really original design. 80 grams for the rig is nice. I like the way the Picavet arm serves to protect the camera, and the way the camera controls are more accessible than in a soda bottle rig. I think you're right that slimmer stock would have plenty of strength for this. The best part of the design is the way one piece of bent aluminum serves as legs, camera attachment, camera protection, and suspension attachment. This got me thinking of modifications to exploit that concept. Your design is kind of a hybrid between Picavet (four rig-attachment points) and pendulum (hanging from one line-attachment). Your design eliminates an advantage of both the Picavet and the pendulum. They both damp or prevent spinning, but your single string attachment does not, so you added a vane. That vane will be a problem on no wind ballooning days when the rig slowly spins until the vane hits the balloon line and then starts bouncing back and forth, possibly increasing spinning motion.

The Picavet version below would be for kiting when a two point attachment to the kite line will damp motion. The pendulum version is for kites or balloons. The attachment to the line would be like Becot's design which damps swing and eliminates spinning. Both of these designs not only make the camera controls accessible but make it easy to see the LCD (both are essential features). The legs could be extended and wrapped into a cage to protect the camera as much as you want. Once the 3/4" aluminum stock is split lengthwise it should be easy to shape. These designs do not pack away very compactly, but you can't have everything.

PendulumPicavetDes2k.jpg

In the Picavet version it is important to keep the four Picavet eyes well above the camera (the center of mass) so it will self-level. Also, my rectangle of eyes might not work as well as a square or diamond. In the pendulum version the upper arm has to bend in so it is centered over the mass. I guess we have to call these the Gumby rigs.

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Ha! I like the name "Gumby rigs". Thanks for the link to the Becot design, that gives me some ideas for the future. Spinning was the main problem on our first flight because I was using a Picavet on a balloon with no wind to speak of so I had no horizontal distance between the attachment points. The spinning caused almost a third of our images to be too blurry to use. On the flight for which I used the above design, it certainly did spin, but not fast enough to blur so we were able to use 100% of the images. As you mentioned, the vane did make it "ping pong" back and forth as it hit the tether but it was never fast enough to cause problems. Under different wind conditions, we might not be as lucky. We were experiencing wind on the ground between still and 2MPH but it was quite above that (don't know how much) at 50m and above. If someone needs constant orientation, this design probably would not work without modification. But since we were taking many images and stitching in software, my only concern was blurriness. Thanks again for the tips!

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