light up

This is not a tutorial -- I have a new flexible foam prop that I developed. I want the eyes to light up on activation and also to add a dimming effect. I would like to know if anyone has any experience doing something like this? My plan is to embed a 1" diameter, spherical casing with an LED...

I'm trying to build a character (I'm in the development stage) that has a exposed heart on his chest. I want it to light up and beat with sound. I'm willing to settle with just a light-up heart, but I don't want it to be color changing. I was thinking as a last resort I could get the color...