MedPundit links to this BBC story about a Spaniard who has invented a device to translate baby cries and "tell harassed parents if their child is hungry, sleepy or tired". MedPundit (last entry on the 15th if the link doesn't work) lists the story in the category "Dubious Inventions".

Neither source mentions that an entire Simpsons episode was built around precisely the same invention. The title is "Brother, can you spare two dimes?" (third season), and the inventor is Homer's half-brother Herb, who had been living under a bridge.

I won't ask whether the machine works, but if it sells well, could someone from the show ask for royalties? Since Herb is a fictional character, who would be able to claim royalties? The writers, the producers, the Fox network as a whole? Whichever (if any) of them had the foresight to patent the idea? Only the last, probably, though I wouldn't know. The episode actually gives a patent number (214661767): I wonder if it is genuine. I also wonder whether anyone else has ever made money from 'borrowing' a fictional character's invention.