Have you ever been making a project with LEDs and found that those clear bright LED's hurt your eyes? Have you ever used a tri-color LED and really wanted more of a blend of the colors, rather than seeing the three separate colors?
You could just buy diffused LEDs, but that is not the point. Also, it is impossible to find diffused tri-color LEDs.
One quick and dirty way to diffuse the light is to use a small piece of drinking straw. Yep thats right, if you cut off a piece of straw and just slide it over your LED, it will diffuse it for you until you find a better way.
The favorite solution at hacktronics is: sandpaper. Your old woodshop teacher would be proud. Its pretty simple actually. Find some fine grit sandpaper (use something over 200), and lightly sand that clear LED until the entire lens becomes cloudy. This will make the light glow across the surface of the LED lens.
Below is the before and after. For this example we use the Red and Blue colors within the LED to make a purplish color.
In the original, non-difussed LED, you can see on the paper, the two seperate colors of red and blue. However, after we diffused the LED lens with sandpaper, you can see that the color is blended, giving the LED that purple glow.