On Fri, 28 Dec 2001, Jinx wrote:

> > How much LEDs (of the average, 5mm/20mA kind) must I roughly
> > use to make a 7-segment display that has good visibility in
> > 'average' outdoor daylight? The application is a countdown display
> > for a car race, each digit 20 .. 50 cm high. Any experience, URLs?
>
> I thought it would be far simpler and cheaper to use magnetic
> segments made of aluminium. One side is black, the other side
> is fluoro-yellow, and they can be flipped using a (home-made ?)
> solenoid pulling a lever. They can also be made larger with no
> increase in cost. A good source of thin aluminium sheet is printing
> plate. Ask at any decent-sized printers, they throw a lot out

Another option would be a colored plasic sheet with 7 segments masked off,
lit by brake lamps under PIC control with MOSFET drivers.  No moving
parts, which I like better.

Dale

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