Hi, this project was my christmas present to my girlfriend this year. What it does is that every time the bear is hugged, the heart fades in, pauses, and then fades back out. I got the bear's skin from build-a-bear. The brain of the bear is a LilyPad Arduino Board. It is powered by a 1000mah 3.7v LiPo battery that is rechargable via a usb cable that is stored inside the bear. The bear senses the hug with a 4.5" flex sensor that is sewn into the back of the bear. For the heart, I made a paper template and sewed the LEDs in place on it. I then just sewed the LEDs into the bear with a red felt heart covering them.
I removed the thread that was already in the back and replaced it with some velcro for easy access. I also stuffed him myself cause I really didnt feel like trusting the build-a-bear people to not hurt the electronics.