[sdiy] super-nice LED interface ..

[Colin f]

> I'm not personally impressed by this, I think  capacitive 
> sensors are more
> practical.
> You are going to need a certain amount of processing to try 
> to work out what
> is going on.

I don't think it would be too arduous to get something simple going.
Drive every LED on the odd rows on for a very short pulse to detect a finger
on the even rows.
Then pulse the even rows to detect fingers on odd rows.
Then have a longer period scan of all LEDs to indicate their current status.

But you're going to need a lot more processing if you're going to make it
insensitive to ambient light...
Notice that the photos show it being demo'd in the dark.

Cheers,
Colin f