Matt Brailsford has taken an old cassette player and stuffed it full of electronics with a Raspberry Pi at the core. The player reads NFC tags which are embedded inside the physical cassette tapes to choose Spotify playlists and there is a custom circuit board beneath the old, physical buttons that trigger commands on the Pi to pause, stop, play etc. You can see a video of the player in action below. Photo credit: Matt Brailsford