Plywood Cam

Capture the moment of ignition

An Astrocam takes to the skies with a D12.
Plywood cam was born the night before a rocket launch. In it's first incarnation, it was an R/C receiver, servo and cheap camera (Vivitar T200... $10.00 US) screwed to a piece of plywood, hence the name. With an average of four good pictures from a roll of 24, it was decided that the human operator needed to be taken out of the picture, so to speak. In it's latest form, Plywood Cam is controlled by the rocket's exhaust. It's simple one IC circuit rotates a servo that pushes the button on the cheap camera. The circuit is triggered by a photocell.

Delay timing is accomplished by simply adjusting the arm of the servo (with the potentiometer) a certain distance from the button. All the parts from Plywood Cam can be found at Radio Shack (except the servo).

The 555 timer IC and it associated parts can be mounted on a little perf board (also available at Radio Shack). Drill two holes in the aluminium panel to mount the potentiometer and the slide switch. The battery pack is attached to the back of the box. The servo will be mounted later on the side of the box with double faced foam tape. Two more holes are required for the battery wire and the photocell wire. These will be drilled through the plastic box. The photocell is placed in a 18mm motor mount and glued in at one end. This will act as a lens to reduce stray light from fooling the trigger. When the photocell has sufficiently cured mount it on a piece of 1/8 inch launch rod.

Now it's time to build the plywood ring which holds everything together. The four pieces of plywood will be glued together with epoxy to form a 2.5 inch deep picture frame. The exact dimensions of your frame will depend on the camera and box size. Place the box and the camera on a table and arrange them so that the camera button faces one wall of the box. This is where the servo will be mounted. Make a note of the dimensions of your arrangement and cut the plywood accordingly. When the epoxy glue has set up enough, mount the camera with elastic bands. Do the same with the control box. Mount the servo with double faced foam tape. Make sure that the servo arm can trigger the camera.

To use Plywood Cam, set the camera up a distance of about 1.5 yards from the rocket. With the camera looking up at the rocket, compose the picture so that there is some sky above the rocket. Mounting Plywood Cam on an old tripod really helps. Set the photocell on the shady side of the rocket and point it at the flame, about 12 inches away. Turn on Plywood Cam. Turn the potentiometer so that the servo arm is close to the camera button. Arm the camera. You're all set.

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