Light Sensors

Cameras@ LED@ Wearables@ Infra-Red I/O@ Fiber optics

Richard Ottoson says:

...a quick rule of thumb about opto's:

• Photo diodes have about a 1us response time,
• photo transistors have about a 10us response time, and
• photo darlingtons have about a 100us response time.
• CdS (Cadmium Sulfide) photo resistors have about a ___s response time.

These times assume a "reasonable" resistor value. There are amplified optocouplers that are in the 100ns range as well.

A Primer on Photodiode Technology http://www.centrovision.com/tech2.htm has some simple circuits for photodiodes, and tons of nit-picky detail on how they work.

Brian Kraut says:

Go to your local disco and theatrical lighting supply store and ask for for a gell sample book. Voila, about 100 different color plastic filters in 1 X 3" size. Some of them even have spectral response graphs for each sheet.

James Newton Says: " For optical interruption sensors, don't forget your standard super low cost "mechanical" mouse! " +

Phototransistors +

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