Does anyone know of a moderately cheap gadget that I could strap onto my head at night which would detect REM/non-REM sleep and that would trigger short bits of

Does anyone know of a moderately cheap gadget that I could strap onto my head at night which would detect REM/non-REM sleep and that would trigger short bits of audio that I had previously recorded? Is anybody out there doing anything like this which I could try to copy and see if this might work? Any references to anything related would be greatly appreciated. Thank you