On Tuesday, July 14, 2015 at 7:07:23 PM UTC-4, wrote:
I bought today a "hands free" garbage can for the kitchen. It said on
the box that it has a motion detector for hands free operation. The
unit as a whole is well made and has features I like. The problem is
that when slid under the counter the motion detector detects the
underside of the counter and the lid opens and stays open. So it must
detect reflected IR, whether moving or not. The under counter position
is where it must go. The hands free opening is why I bought it, it is
for use in the kitchen. All the electronics are in the top, which
comes off in order to remove the garbage receptacle. So I need some
sort of sheet IR absorber so that the thing will work properly under
the counter. I can operate it manually but I don't want to touch the
garbage can when I'm cooking and have food of one sort or another
stuck to my fingers. Anybody have any ideas? I thought about maybe
taking the thing apart and putting a mirror inside that would make the
sensor see at an angle so that it wouldn't detect the underside of the
countertop but then it might open when someone walks past. So it looks
like what I really is a good IR absorbing material that I can fasten
somehow to the countertop underside. Any suggestions?
Thanks,
Eric

Black electrical tape works very well at blocking all the
light from (Si) photodiodes. I don't know how much
is absorbed vs reflected. But it's easy to try.

George H.