The motion sensor triggers a motor...for this I have been directed to look at toys that replicate the movement I require.

an umbrella?  a grabbing toy, maybe a crane or something...

I've seen a flex that open and closes an animated flower on screen that looks great but isn't what I want.


I've been through boxes and boxes of the kids toys and the only thing 
I can find that might fit the bill is Nemo. 
Noah (my son) doesn't know I've taken it yet. 

The alternative is this Christmas present from his dad. Tempting though it is, forty seven pounds worth of plastic is too much money to hack into for me, maybe if it were a few years older...
so back to foraging.