There is a pretty well-populated list of optical sensor manufacturers at http://www.sensorsportal.com/HTML/SENSORS/OptoSens_Manufacturers.htm for starters. Also, another rather large list of manufacturers and suppliers is located here: http://www.thomasnet.com/products/optical-sensors-73749350-1.html. As for information on them, wisegeek.com has a good article on them here: "http://www.wisegeek.com/what-is-an-optical-sensor.htm" Hope this helps!
You can find them at AMeds.com Look under health care.
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You can post information regarding the types of sensors your looking for on industry specific websites. Many manufactures look to these sites for leads.
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You can find more information on optical drives on internet review sites or blog post made by users. More information can also be found at local stores.
There is some info at http://www.keyence.com/products/sensors/ultrasonic/ultrasonic.php. They are a manufaturer of them.
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Find the manufacturers information from the different vendors through NAPA or O'Reilly's. Then you can typically find the information via the web.
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