you should contact m.rueger or yoshiki since I remember at esug last year they show how people linked a heat sensor to etoy.
It is "World Stethoscope". The website is a bit out-of-date in terms of the hardware, but basically the hardware converts various sensor readout into the pitch of sound, and the eToys code can use the pitch as a variant of number tile.
Ask the author Mr. Kazuhiro Abe (I think he is on this list as well) about the latest hardware and software.
-- Yoshiki