The world’s smallest televisor
This machine is called The Nipkow Nipper because Paul Nipkow invented the mechanical scanning disc in 1883.
Most NBTV (Narrow Band TV) builders like to produce as large a display as possible. I decided to try and go smaller if possible.
I have an old Ensign Selfix 120 rollfilm camera that can take 2 1/4 x 2 1/4 square inch images on film and thought that if I could photograph a 12 inch dia Nipkow onto this film it would give me an image some 2 inches diameter, quite a tiny Nipkow disk The resulting NBTV picture will be approx .180 inches x .120 inches. from this spinning disk.
The scanning image holes will be .004 inches dia and the sync holes about .012 inches dia.
An infra red opto fork is not suitable for the filmed Nipkow sync hole images as the emulsion does not obscure the fork's emitter. A tiny light detector is used with a change of voltage detector to create the sync pulses.
I made a jig to hold my old Ensign Selfix 120 rollfilm camera (104mm lens), together with the club's Nipkow disk on the same rig, mounted approx 2 feet from the camera to get my 2 inch dia Nipkow disk image on film. This image cut out to form a 2 inch dia Nipkow disk, to be sandwiched between 2 large perspex washers for film stability.
The film used was Fujichrome reversal. 12 shots on one film to give various exposures for best results.
I used a piece of frosted material positioned where the Ensign Selfix's camera's 120 film runs to examine the camera's image of the Nipkow disc to get the camera focus correct. (Close up lenses required.)
Unfortunately the photos produced were not in sharp enough focus so I took a underexposed shot and using a tiny needle pierced the film right through were the scanning images were. This also gave more light through the film. The bottom pad controlled
the hole diameter.
To enable this tiny picture to be seen a small video camera is mounted on the left hand side and its picture is shown enlarged on a vertically mounted car reversing monitor.