Taking basic pictures with lego mindstorm or any other robotic device :

A theorical approach

©Philippe Jadin

You should visit my robot page first (if you care...)

This document describe how first experiments were made by Paul Nipkow (1884) to make a tele-vision system. This can be extrapolated to mindstorm with a light sensor, a motor, and a rotation sensor. No practical tests were made yet, but if anybody is interested, and has made some experiment, please contact me. I'm very interested by the subject.

The Nipkow disk is a disk with holes in it, placed in spiral. Each hole give one line of video signal. With 16 holes, you get 16 lines. While one hole is scanning the projected picture, several samples are being taken, which do represent the horyzontal resolution of the signal. Take a look at the pictures bellow, and let me know if you do understand something... Sorry for the poor clarity, but i just have no time by now... I'll post more info's latter.

fig 0. the Nipkow sytem as described in "Sciences & Vie n°831 December 1986)

(Image © Sciences & Vie)

Fig 1. Overview of the system

fig 2. Left view

fig 3. top view (very usefull, as no label can be read :-)

fig 4. perspective view

fig 5. A zoom on the disc. Note that the size of the projected picture is different from the range given by the holes. To see the exact way it works, look at the first picture. The others will be fixed later...

To be continued...