This is a pretty interesting walk though on how to process and read the microvoltage that an LED will put out when exposed to a light source . Who says you can’t teach an old component new tricks?
“Hook up a high-quality ultra-bright red LED by itself (no battery or other circuitry) to a multimeter in voltage measurement mode. Put the LED against a light source, such as a desk lamp. See the voltage? Now, hide the LED in a dark place. See a decrease in voltage?”
Via Make
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Um, last I checked, All semiconductor materials are photo sensative. granted some
more than others. and your article only shows that it is light sensative, not
color sensative.
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Some interesting (human EE filtered) related reading when you’re planing on using a single led for digital communication between micro-controllers:
http://electronicdesign.com/Articles/Index.cfm?AD=1&ArticleID=15980
Hope it helps someone =)
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Hey Jeff,
The article shows how to do it for one color, simply make the same circuit 2 more times for the others (RGB – Red Green Blue)
“Putting this all together – a color sensor can be made from a reversed LED and an op amp chip. In fact, TAOS did just that with their TSLR257 (red), TSLG257 (green), and TSLB257 (blue) sensors.”
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Lawrence, your comment was removed. Please refrain from posting negative non-constructive comments. We appreciate all feedback, if there are certain types of articles you enjoy more than others please let us know. 🙂
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How much current does a regular led produce in direct sunlight? Is that reading there in mA?