Dave Bell wrote: >Well, I *have* seen solar powered walkway lights, too. This does bring to >mind the "Sun Pointer" motorized "dial" that was published. I could see a >long arm carrying a pin spot, that would rotate through the solar path, >180 degrees out of phase with the real sun...
Many years ago a group of students demonstrated their 'robot fire engine' to a visiting VIP. The sensor was basically a scanning parabolic reflector and a thermistor arranged to home in on a fire then squirt water on it.. To make the demonstration more realistic a real fire was lit in the courtyard and the robot was sent to put it out. After an initial scan it quickly ignored the experimental fire because it detected a much bigger one high in the sky! Having carefully aligned its hose it then tried to put the sun out. In hindsight it had all the makings of an interesting mechanical sundial. Tony Moss -
