Tom=E1s =D3 h=C9ilidhe wrote:
> Exactly, I'll multiplex them one LED at a time. This way, I'll have no
> need for drivers at all.

Only if you can tolerate very dim LEDs.  If each LED will only be on for a
short time, the current during that short time will need to be large to get
the same average current.  For example, if you have 50 LEDs with never more
than one on at a time and you want 10mA average for a LED that is lit, then
you'd need 1/2 amp thru the LED during the brief time it is on.  You have to
look carefully at the maximum instantaneous current spec for the LED.  You
would probably exceed it with your propsed scheme.

> Plus I can work off two AA batteries (i.e. 3 volts).

Without a boost supply for the LEDs at least, the LED brightness will vary
greatly over the battery life and the batteries won't be usable even when
there is still some life left.

> Are you definitely sure that the 887 running at 8 MHz will be good
> enough?

There is no way to tell because you haven't explained what exactly it has to
do beyond multiplexing the LEDs.


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