LEDs as light sensors

Step 5 Add some programming

Now that we have some nifty LED sensors (aka - normal LEDs) it's time to make them do something. I make a quick Arduino sketch that turns on an LED when it gets dark. The code is very straightforward; when the voltage from the sensing LED goes below a set level the Arduino knows it is dark and turns on an LED. I used the red super brights for the sensors because they had the best range (IR was too sensitive).

Testing:

Straw diffuser on the blue leds for a dark detecting night light:

Note: This program is just a simple example I thought of and made in a few minutes. This is by no means the only thing you can do with this concept. The meat of this instructable is in the experimenting.

Now that you know how to use LEDs as light sensors go and make something awesome!

Comments

[kcd12321]

Really interesting and cool. The straw had a great effect.