[sdiy] super-nice LED interface ..

[Paul Perry]

----- Original Message ----- 
> but .. all LED's are on in that demo, so does this mean that the
> array has LED's that are 'off', but still being used as a detector,
> or does it mean that LED's can be used as detectors even when lit?
>
No, as you can see from the diagram on the page, the leds alternate in such
a way that
ones adjacent to the point being examined are on, and the light diffuses
through the finger
(or possibly reflects from it) to the middle one, which is at the same time
in receive mode.
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.

paul perry melbourne australia