Roff
Well-Known Member
I know there have been discussions on these forums of LEDs as light sensors, but I don't remember seeing one used like this.
Fig. 1 **broken link removed** is a night light that uses the same LED for sensing and for illumination. I breadboarded it, and it worked. I'm not sure how useful it would be, but it demonstrates the principle nicely.
Fig. 2 supposedly works in the opposite fashion, but I didn't test it.
EDIT: Here is a more complicated, earlier version of the same idea.
Fig. 1 **broken link removed** is a night light that uses the same LED for sensing and for illumination. I breadboarded it, and it worked. I'm not sure how useful it would be, but it demonstrates the principle nicely.
Fig. 2 supposedly works in the opposite fashion, but I didn't test it.
EDIT: Here is a more complicated, earlier version of the same idea.
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