GRAB a handful of pistachio nuts and you will usually find several with shells that are closed so tightly they cannot be eaten. But soon you might be able to enjoy the snack without this frustration. A gadget that listens to the distinctive pings made by nuts when they bounce off a surface could help to sort open-shell nuts from uncrackable closed ones.
Ripe, open-shelled pistachios, which fetch top dollar as a snack food, have to be separated from sealed unripe ones, which are normally shelled mechanically for use in ice cream or cake mixes. But the spinning drums that…
