A very inexpensive one is Accutrans at  http://www.micromouse.ca/ 

it's free and un crippled to try but only $20.00 American so that's a pack and a half of smokes up here...well 2 packs...LOL...it's an honour system so please honour him if you like it and keep it..

 

Once in a while I look around,
I see a sound
and try to write it down
Sometimes they come out very soft
Tinkling light sound
The Sun comes up again