This instructable will explain how to create your own light sensing LED,making some changes,programming the microcontroller,makingit on a breadboard and soldering the circuit.
A short video of it in action:
Step 1: How Can The LED Sense Light?
The LEDs will be sensitive to the light which has the wavelength equal to it or lesser than it.
When light falls on the LED a small voltage is produced this voltage produced can be fed to a microcontroller which can read it and follow the further instructions.
Step 2: Parts & Tools
~ PICAXE 08M2 Microcontroller - Sparkfun.com
~ 330 Ohm Resistor - Sparkfun.com
~ Green or Red LED(I used a green LED) - Sparkfun.com
~ 10k Ohm Resistor - Sparkfun.com
~ 22k Ohm Resistor - Sparkfun.com
~ Audio Jack - Sparkfun.com
~ Soldering Iron - Sparkfun .com
~ Solder Wire - Sparkfun.com
~ PICAXE Programmer - Sparkfun.com
~ ProtoBoard - Sparkfun.com
~ BreadBoard - Sparkfun.com
~ PICAXE Programming Editor - Picaxe.com
~ Audio Cable 3.5mm - Sparkfun.com
~ A to miniB USB Cable - Sparkfun.com
Note - Use only green or red LED and not any other color as the LED's of these two colors are the most sensitive to light.
The total cost would be around 5.55 $ assuming that you have all the tools.
Step 3: Programming
Here's the sensitive to dark code
if b0 < 10 then dark
Here's the sensitive to light code
if b0 > 10 then light
If the programming finishes properly a pop up window will appear saying success and will display the size of the sketch.If something goes wrong please feel free to ask.