Notes on Kite Aerial Photography: Equipment

A Low Cost Ice Trigger
Notes from Bill Nelson


Toward the end of 1997 I exchanged a few messages with Bill Nelson about the development of low-cost KAP rigs based on reusable cameras.  It seems the most vexing problem about designing a low cost rig is the timing mechanism to release the shutter.  I like many others have used a mechanical destabilizing timer from the model aircraft world -- not really low cost at $25.  Bill described his development of a truly low cost mechanism and kindly agreed to share it with you.

The following is Bill's description of his approach as described in his e-mails, the photographs are images of New York that Bill took with his rig.

Cris Benton, April 1998


msspqa.gif (43774 bytes)Massapequa, Long Island, looking south toward the Great South Bay taken with the ice cube timer, triggering a disposable camera of the "panoramic" type. (30K jpg).

Bill Nelson's Ice Trigger Notes:

Four years ago I decided to take some kite pictures of my own, and I wanted to find a way that was cheap and simple.

I succeeded. Here's the story.

My first idea was to get my hands on a hypodermic syringe and head for the Empire State Building to begin testing; the reduction in air pressure at a thousand feet would push the plunger of a sealed syringe outward. I figured I could set the syringe up in such a way as to trigger the camera when the kite reached a planned altitude -- but too complex.  So...

Next my local hobby shop owner suggested I use a dethermalizing timer (as you did); but after some kite flying experiments with one eye on my wristwatch, I decided that six minutes would not allow enough time for my kite to reach the desired picture taking altitude (in the beginning I had plans to send a camera up very, very high--but more about that later).

I'm sure I could have used two or more timers in some sort of gang arrangement, but I wanted to find a simpler way still. I remembered reading in a kiteflying book written in the 1920s of a suggestion that a burning fuse be used as a timer. Though cheap, that seemed dangerous and too unreliable. Still, the idea had some appeal; it would have been a simple and inexpensive. (Though the idea of a lofted storm match gives us Californians a scare - we are prone to serious wildfire here.  Ed.)

The idea of a burning fuse inspired me to develop what I called a "wet fuse"--a string made from paper-mache, or a cube of sugar -- that would weaken as it soaked up water. To accomplish this, I needed to add water to the material over time, thereby gradually weakening the material until it broke and tripped the camera. I thought of various ways to do this, the most basic being a version of the ancient water clock (just a container of water with a drip-hole). But then I thought... ICE.

msspquaw.gif (41787 bytes)Massapequa, Long Island, looking west, toward New York City (30K jpg).

Thinking I could use a melting ice cube slowly to soak and weaken a paper towel or sugar cube to its breaking point, I suddenly realized that the ice cube itself could be the timer!

Here's how I did it. I made a small balsa wood tower (it looked liked a miniature oil derrick) to suspend a coil-spring loaded plunger above a disposable camera's shutter button. The spring loaded plunger was held aloft against the pressure of the coil spring by monofilament that passed up and over the top of the tower, and over an ice cube which sat on a shelf to one side of the tower's top. From over the ice cube the mono descended at a 45-degree angle to a fastening point on the camera body.

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As the cube melted, the mono would slacken and gently begin to lower the plunger to the shutter button until the shutter tripped. The thing allowed some timing adjustment too: How long it would take to trip the shutter depended both on the size of the cube and on how far the plunger was retracted from the shutter button.

ballfield.gif (42191 bytes)Picture  taken over a schoolyard in Selden, Long Island (New York), in 1990 or 1991.The pink Ande monofiliment I used as kite string can be seen as a pink blur descending to where I, a white and black speck, am standing (33K jpg).

This whole assembly was then turned upside-down (in addition to being the more stable configuration, this prevents the ice as it melts from dripping onto the camera). The camera was then fastened to the kite string by means of a Popsicle stick taped at right angles to the camera body, then fastened fore-and-aft to a taut kite string by spiraling the kite string around the stick and securing the string to the stick’s ends with tape. The stick helped to keep the camera generally pointed in the right direction for a photo of the ground with a little of the horizon usually showing.

There were some other, finer points:

  1. To better secure the cube (slippery devil), I would file a notch in the ice cube for the monofiliment to ride in as it passed over the cube.

  2. I also fastened the camera to the string some distance down from the kite--instead of to the kite itself--so that I could first send the kite up a bit to develop some real lifting power.

    This also allowed lowering the camera to ready it for the next picture--without having to land and re-launch the kite for each shot.

  3. With the kite aloft, I would take another ice cube from the cooler and place it beside me to better predict when the ice cube on the kite had melted.

  4. My kite or kites (in light airs I would use two kites flown on the same string) were the run-of-the mill little plastic jobs first made popular when sold as "Bat Kites."

The experiment was a success. I can’t remember the ice cube timer ever failing me. I did have many problems with blurring (too-slow a shutter speed, though I admit I might have found a more stable way to "fly" the camera.) I managed some passable photos from heights approaching seven to nine hundred feet. I lost interest when I found that it’s illegal around here to fly a kite more than a few hundred feet because of air traffic. That ended my plans for stratospheric flights. Too bad; there was plenty of room for improvement.

I even dreamed of using wind power to wind the camera for repeating shots (I noticed that if you held the shutter button on those disposable cameras down and advanced the film, the shutter seemed to go off whenever the film advanced to the next frame. So, with half ping-pong balls on arms connected to a vertical axel ending in a gear or rubber wheel pressing against that serrated film advance wheel at the back of the camera....

Alas, I had other demands on my time.

cpbridge.gif (34222 bytes)A drawbridge that leads to Captree State Park in Long Island, New York (17K jpg).

Of course having to predict when the ice cube was aloft long enough to have melted was an inexact science, and you might think that watching that ice cube beside me melt was boring, there were always spectators to keep me entertained.

You see, I used a stout fishing pole and multiplying reel to fly the kite, which I did at the shore with a cooler for the ice cubes and a small tackle box for assorted tools, string, and monofiliment beside me, making for some humorous exchanges when passers-by would ask "Catch anything?" And I, holding the rod the while and with no camera in sight, would reply "Not fishing, taking pictures." It’s a wonder the butterfly nets weren’t after me. I guess they figured I was harmless in that location, being far removed from traffic and all.)

Lastly, not counting the price of the disposable camera and the price of a freezer, the apparatus could be built for a lot less than $10. In fact, there’s probably enough junk lying around the average garage or basement to do it for the price of the glue--if you needed that even.



oldcam.gif (39055 bytes)
Bill Nelson also sent an image he found in an old book, "Kites and Kite Flying," published by The Hamlyn Publishing Group Limited (1978). This image shows a large Cody with two(!) large cameras mounted on the kites "wings." Curiously, the caption that accompanied the picture made no reference to the two cameras, reading instead: "Cody kites can be scaled up to a considerable size by reason of their strongly braced construction. The balance created between their lifting and stabilising surfaces makes them very suitable for man lifting." (34K jpg).




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