magic backpacks

Magic backpacks lets you bring your toys to life. Strap a backpack on to your teddy bear, and suddenly it has some behaviors- it says "whee" when you throw it in the air, or giggles when you hold it upside down. If it senses your warmth, it purrs like a kitten. In the dark, it gives off a gentle glow.



Here's an earlier description of this idea.

The trick is tighten up this idea. How do you "program" the behaviors, or at least decide which outputs map onto which inputs? Maybe the whole thing is really simple- each backpack has exactly one behavior (e.g. a light), and you can either just turn it on with a button, or attach a sensor pack that controls it in a pre-defined way. Then the question is, what is a good range of outputs that could do something satisfying when you attach them to a teddy bear, an action figure, a toy train, a baby doll, a race car, etc.