[user24]

I'll tell you what else seems to always be listening - the camera on the MacBook Pro, even when the little green light is off.

Cover the camera with your finger or shine a flashlight/mobile phone screen into it, watch the keyboard lights react. It's obviously listening for light level changes.

I just wonder how much data you could collect from the sensor without the green light turning on?

edit: I'm wrong, see my reply to jcromartie

[jcromartie]

If you look closely, there's actually another dot next to the camera. That's the ambient light sensor.

[user24]

You're right. I thought that was the LED but it's not.

Well now, what am I going to do with this tin foil hat I just made?

[jsilence]

Not sure about this one. Fiddling a little bit, I'd rather say that there is a light sensor left of the camera. Blanking only the camera does nothing, blanking the spot just left of it triggers the backlight dimming.

[Argorak]

To be precise: in old macbook pro versions, the sensor was in the speakers. The unibody macbook moved it next to the camera:

http://osxdaily.com/2010/05/22/where-is-the-ambient-light-se...

[meepmorp]

Yeah, this used to cause trouble for me at work. The way my office was lit, moving my hands too far over the (right?) speaker would suddenly change the kb lights and screen brightness. Turned the auto brightness after a couple hours and never re-enabled it.

[wladimir]

Right -- I'm not sure about the MacBook, but in many cases the webcam led is software-directed, not hardware-directed. So a small change to the driver (or firmware) can make it record without enabling the led.

[ugh]

In Macs it’s directly wired to the camera. If the camera receives power the LED also receives power.

[wladimir]

That's interesting. Seems they thought about it and chose the most secure way, then.