If that is the case, then super bright LED should be considered.  This
will shake the requirement.  The traffic light in my
country(Singapore) would be all converted to LED matrix in the next
year.  Don't ask me what are they going to do with the good old
traffic lamps would be replaced.  I don't know.

Ling SM

>This circuit is *VERY* similar to traffic lights on major
intersections with
various patterns involving left and right turning lanes, etc.  I
suggest a
search in some other electronics lists for how they handle traffic
lights -
varying matrix loads, pre heating, pwm, etc.  It's all been done
before, so
don't try to re-invent it, ask those who did it.

>>     I have to make a 220volt lamp matrix of 7x5 lamps=35 lamps.
With it, I
> will be able to "draw" different letters. If they were leds, I would
only
> need to control a row (or a column) and do refreshment in every
other
> column
> (or row).
>     Does anyone know how to control all these lamps using the fewer
lines
> of
> a Pic micro, and also fewer triacs ?