N_Cook wrote:

Or at least translucent to visible. Hopelessly undiscriminating IR encoder &
decoder on a piece of kit but need to see the LED segment display , which
inconveniently has the IR Rx within it.
I've tried loads of normal materials like polythene,perspex, glass, mica,
silicone rubber.
I know black polythene will transmit the IR of PIR units and block visible
but there is more seperation of f there

Short pass filters are harder to make than long pass. You might try
Edmund Optics.

Cheers

Phil Hobbs
--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510
845-480-2058

hobbs at electrooptical dot net
http://electrooptical.net