Sound-based Pistachio Sorter

No cure for cancer yet, but finally, via Engadget, we’ve got a way to separate the closed pistachios from the open ones:

Now Tom Pearson, an engineer at the US Agricultural Research Service in Manhattan, Kansas, US, thinks he has the answer. He developed a sound-based sorter after noticing the different noises the two types of nut made when they struck the ground. “I could pick the types out perfectly without looking,” he says.

Pearson’s machine drops 25 nuts per second onto a steel plate, where a microphone picks up the impact sound they make. Signal-processing software detects the shorter ping of a closed-shell nut, and opens an air valve to blast it off the line.

Now, if they could apply the same principle to dividing the gross peanuts from the good ones.