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.

Bye.

> -----Original Message-----
> From: Gabriel Callao [SMTP:gcaffese@YAHOO.COM]
> Sent: Friday, 12 November 1999 0:19
> To:   PICLIST@MITVMA.MIT.EDU
> Subject:      220volt lamp matrix
>
> Hi all,
>
>     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 ?
>
>
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