Olin Lathrop wrote :

> Jan-Erik Soderholm wrote:
> > Actuly, if one had a spare tube of 12F629's, one could mount
> > one directly behind each LED, running on the INTOSC. Then you'd
> > get a natural "drift" between the lighthouses :-) :-)
>
> Actually that doesn't sound like such a dumb idea if you used a 10F200
> instead of a 12F629 for each LED.  For each lighthouse you'd
> need an LED, a resistor, and a 10F200.  Write a generic 10F program
> that had a dedicated area for the on/off times table, then customize each
> one on the fly.

Hm, using the SOT package with a SMD LED glued on top and power through
conductive paint on the map and you'd not even have to make holes in it... :-) :-)

Now, back to the real project...

One thing I thought about after my last post, is that "real" lighthouse
(that has an rotating prism inside the top with a constantly lit lamp
in the middle) doesn't just come "on" and "off". There is a typical
"attac" and "decay" when you look at it from some distance. Now, this
would probably be much harder to implement (PWM-drive of 20 LEDs from
one 16F877) then to just switch them on and off. Maybe using a
local 10F200 to handle only the PWM and a central larger MPU
that handles the timing ? Then all 10F200's could also have the
exactly the same firmware...

*If* one could get the LED's to switch on and off "softly", I think that
the overall visual impression of the map would be a bit better, but it
would of course work without that also...

Jan-Erik.

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