Constant Current Led Drive

wkrug said:

Have You thought about IR Receiver Chips like for a TV Set?
The sending Diode has to be modulated with 38kHz and the Part spit's out a digital Low / High signal.

Vishay writes something about 45m Range.

Click to expand...

Yes. I was thinking of HS0038BD for that purpose. To be honest, im not sure about this receiver is suitable such as my application requirements. For 20cm max distance , i think this can be handle. For receiver , im thinking of use TSAL6200 ir leds.
But need to be sure and want to know your thinking about the receiver sensing angle .
As i told before , each ir receiver must detect ir light from in line with it. So it musnt detect any of other ir leds. Now here i need some help about choosing right component for max 20cm distance between barriers.

There is" Relative Radiant Intensity vs. Angular Displacement" curve at the datasheet but im not sure how to synthesis this informating to my application. I think this is the key for above question.
Is anyone know , how to use this curve ?

I've read the full thread and have no idea what the OP is trying to do. Are you trying to measure distance by the reflective intensity? What has the picture of a fence got to do with it?

Mike.

Pommie said:

I've read the full thread and have no idea what the OP is trying to do. Are you trying to measure distance by the reflective intensity? What has the picture of a fence got to do with it?

Mike.

Click to expand...

Or how are the 100 LEDs arranged, or why do they need to get brighter at greater distance, and greater distance from what?