Pinhole cameras

A pinhole camera is an old concept. With a small enough hole an image can be projected on a plane opposite to it.

Incidentally, this mechanism is quite independent of the wavelength observed.
The optimal size of the pinhole is calculated by this formula:

Where f is the distance from the hole to the plane, lambda is the wavelength, and d is the pinhole diameter.

Digital back

The image, projected from a pinhole will be quite faint. To read it off, we need a good sensor.
Normally, that would be a job of a CCD matrix or somesuch, but that's not our way.

Photodiodes are made in a variety of wavelengths, and are normally senitive enough for the task. With only one photodiode it have to be moved across the image plane.

So, here is the basic design.
Make a box:

Make a pinhole mount in it:

Put a cartesian robot inside:

Put sensor on the robot:

And you got a camera. :)

Details follow on the next page