I know there is a credit card sized passive device that will take charge = when exposed to visible light. On the card there is a small window which = is used to test ir remote controls (this device is used by tv repair = guys). It glows up when hit by the ir light. I don't know what kind of material it uses or where you can get it (I = just can't remember)... Anders ----- Original Message -----=20 From: "Jinx" To: Sent: Tuesday, June 12, 2001 12:52 AM Subject: [EE]: IR fluorescence > Many substances fluoresce under UV light. Are there any > which do so under IR or are the energy levels all wrong ? > I think short wavelength UV is converted to longer wave- > length visible light by the fluorescee and IR is longer than > visible. Just wondering if there's some quirk of nature/ > physics that would make it possible to use invisible flood- > lighting >=20 > -- > http://www.piclist.com hint: PICList Posts must start with ONE topic: > [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads >=20 >=20 >=20 >=20 >=20 -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads