jbm@eos.UUCP (Jeffrey Mulligan) (12/31/88)
From article <743@optilink.UUCP>, by brad@optilink.UUCP (Brad Yearwood): > Which brings me to a question. There is a second LED, presumably infrared > emitting, in the Mouse System mouse, to the left of the red LED. If you > look carefully (particularly if you cover the red LED), the infrared LED > appears to have a pale bluish-gray glow. If you look even more carefully (particularly if you exclude all ambient light), the infrared LED or whaterver it is is completely dark. Presumably the blue-gray appearace is due to ambient light being concentrated by the lens of the thing, which may have a bluish tint. -- Jeff Mulligan (jbm@aurora.arc.nasa.gov) NASA/Ames Research Ctr., Mail Stop 239-3, Moffet Field CA, 94035 (415) 694-6290
dsb@Rational.COM (David S. Bakin) (12/31/88)
From article <743@optilink.UUCP>, by brad@optilink.UUCP (Brad Yearwood): > Which brings me to a question. There is a second LED, presumably infrared > emitting, in the Mouse System mouse, to the left of the red LED. If you > look carefully (particularly if you cover the red LED), the infrared LED > appears to have a pale bluish-gray glow. The Mouse System mouse is an optical mouse. Light goes out, some light goes back in. The second "LED" isn't a led, its a photosensor. I would guess. -- Dave ---------------------------------------------------------- Dave Bakin (408) 496-3600 c/o Rational; 3320 Scott Blvd.; Santa Clara, CA 95054-3197 Internet: dsb@rational.com Uucp: ...!uunet!igor!dsb
ornitz@kodak.UUCP (barry ornitz) (01/03/89)
In article <501@igor.Rational.COM> dsb@Rational.COM (David S. Bakin) writes: >From article <743@optilink.UUCP>, by brad@optilink.UUCP (Brad Yearwood): > >> Which brings me to a question. There is a second LED, presumably infrared >> emitting, in the Mouse System mouse, to the left of the red LED. If you >> look carefully (particularly if you cover the red LED), the infrared LED >> appears to have a pale bluish-gray glow. > >The Mouse System mouse is an optical mouse. Light goes out, some light goes >back in. The second "LED" isn't a led, its a photosensor. I would guess. > >-- Dave Guess again, Dave. I thought this sounded funny, but I just opened up my PC Mouse to be sure. There are two LED's, visible red and IR. Next to the LED's are two spherical lenses mounted in holes in the printed circuit board. These lenses focus the reflected light via a reflector on the top cover of the mouse to two associated photodetectors mounted on the circuit board. A second giveaway is the fact that the mouse pad is printed in two colors giving a different contrast to the red and IR beams. Barry ----------------- | ___ ________ | | | / / | | Dr. Barry L. Ornitz UUCP:..rutgers!rochester!kodak!ornitz | | / / | | Eastman Kodak Company | |< < K O D A K| | Eastman Chemicals Division Research Laboratories | | \ \ | | P. O. Box 1972 | |__\ \________| | Kingsport, TN 37662 615/229-4904 | | -----------------
asmith@ihuxv.ATT.COM (00704a-Smith) (01/04/89)
In article <1574@kodak.UUCP> ornitz@kodak.UUCP (barry ornitz) writes: >I thought this sounded funny, but I just opened up my PC Mouse to be sure. >There are two LED's, visible red and IR. Next to the LED's are two spherical >lenses mounted in holes in the printed circuit board. These lenses focus the >reflected light via a reflector on the top cover of the mouse to two associated >photodetectors mounted on the circuit board. A second giveaway is the fact >that the mouse pad is printed in two colors giving a different contrast to >the red and IR beams. > Barry Yes. Optical mice work with two pairs of LEDs and photodetectors. One pair is used to detect horizontal motion while the other is used for vertical motion. The stripes are different colors because the LED's operate at different frequencies so as not to interfere. One color stripe runs horizontally while the other runs vertically. Art Bug? What bug? That's a feature!! The ideas presented here have nothing to do with reality or my employer.