HI folks....me again with another one of those...how would you do it questions... Some time ago, had a short discussion here about getting longer distances with IR LEDs, and my thoughts on this was to pulse them at a higher current to do this. So picture this setup. A square "bin" or hopper that gets objects ranging from a several inches square (small toys) to a larger item (stuffed animal) and on each side of the hopper is a row of IR transmitters and across is a row of receivers...8 pairs. So the original design when I arrived on the scene was just wiring ORing the rx and the tx was on all the time. However, with the angle of radiation from the tx, you could block the tx across from the rx (the pair) but the rx would still get IR from one of the adjacent tx. I think they told me...each tx IR would have enough angle of radiation to trigger the one across from it...plus each one to the side as well. So, even tho something might have blocked a particular tx beam, the ones next to it would still not allow that one to activate it (ie...turn it on and pull the signal low). OK, so the idea...first pulsing the tx with higher current, and second syncronize the tx/rx pairs so that only when the tx.1 was on, rx.1 would be looking for a signal. Works pretty good, each board has a PIC16F818 on it, and sending a sync from the transmit to the receiver so they lock up. However....as you pull the boards away....the alignment of the beams become more difficult. I didnt increase the power on the LED's yet...told them this morning to try that. But the issue as I see it.....there are now HUGE holes in the sensing pattern. The LEDs are about 1/2" apart and even tho the radiation pattern is the same, its no longer looking at the IR from the adjacent transmitter. So, looking for thoughts on how to get rid of the holes in the sensing field. The answer might be obvious, but you know how it goes...after staring at the problem for so long, you cant see the forest for the trees. --------------------------------- Sucker-punch spam with award-winning protection. Try the free Yahoo! Mail Beta. -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist