Touch buttons

I should add, that it is HP Elitebook. The touch button is a transparent plastic part, probably with LEDs under it.

If it doesn't take any pressure to activate, it most likely senses the capacitance of the finger. It's quite possible it's just contacts under a "dome", too.

Look up "cap-sense". You can start here:

For most uses, they suck. I would think this would be one where they would

What is a "labtop"?

Come on silly, that's the roof or the next floor up!

Jamie

My Dell monitor has these capacitive touch buttons. The led lights when the finger is about 1" away from it and the button activates when you touch the led. If you slowly touch the led the button does not work. If you touch around the led, the button does not work. Which makes me believe there is more than just a led in there.

Cheers

Why? It could be sensing the capacitance change to the LED. There is usually a land pattern for the sense circuit, though. The fact that it doesn't do anything, if touched around the LED, suggests that there isn't, though.

Or perhaps this...

Cheers

An LED sensor would tend to discriminate against people with darker skin, apparently.

--Winston

Ok, there is something "more than a just an LED in there". There's two. Actually, that sounds like a better idea than cap-sense. OTOH, cap-sense sounded good, too, before I actually had any experience with it as a user.

A racist touch button?

Most palm's and fingers I see tend to be lighter skin tones, but you never know....

Cheers

It may use LED as a bidirectional sensor,Paul Dietz, 2003

Lyn