Hi again,
So after some more research I've come to the conclusion that the ultrasonics aren't going to do what I would like - not a wide enough beam and unnecessary accuracy.
Perhaps if I say what I would like 'something' to do, someone may say "oh, you want one, two, n of *these*".
I have a digital wind chime thingy that now works ok on the RPi. What I would like is to be able to put it outdoors with *something* that will *see*when large objects, like people, are coming towards and moving away from it and then I can make use of that data to send force in pmpd to the chimes and then the chimes can klang into each other.
Been looking at the kinects but it seems I'll need GEM to be able to explore Matthias's very excellent looking freenect lib which is a no-no on the RPi currently.
My friend and I have rounded up a nice solar panel, we've got some old broken soundstick speakers that we've hacked into and a weather-proof box plus a pole to hang it all on. Should be a nice little project when it's done but a we're bit stuck on this problem at the moment...
Any suggestions people?
Cheers,
Julian