When it comes to audio, the number of speakers you want is usually governed by the number of tracks or channels your signal has. One for mono, two for stereo, four for quadrophonic, five or more fo… ...

The BBC's vast sound effects library is open to the public. Thousands of clips can be downloaded for free, and people have been pulling out all kinds of weird sounds. NPR's Chloe Veltman did, too.

So we knew we’d need a button, some sound files, a little bit of Python code, and, of course, a Raspberry Pi. A new Pi is $35 , but we found an old Raspberry Pi 2 in my desk drawer, which was up ...