Robert Rolf wrote:

> Edson Brusque wrote:
> >     I'm wanting to make a sensor to tell the distance from an object (user's
> > hand) using an IR emiter (LED) and an IR detector (IR
> > fototransistor/fotodiode).
> >
> >     I've make some tests with little sucess.

I assume your looking at intensity differences, which will only be repeatable across
the same types of surfaces.

> >     The sensor need to be able to detect the distance from 0-50cm, and I'm
> > only having voltage variations from 0-6cm aprox.

> I would suggest using the Polaroid Ultrasonic ranging modules

No, they won't work very well at distances less then about 30cm.

Here is what you need:

Sharp GP2D02

Here is a link that describes it:

http://www.sharp.co.jp/ecg/sys/gp2d02/gp2d02-fea.html

http://reality.sgi.com/barry_detroit/GP2D02_1.html

I've used them before, and they work fairly well once you calibrate them.


-Jeff