[Clare] isn’t the most musically inclined person, but she can strum a guitar. Thanks to a little help from an Arduino, she doesn’t even have to do that. She built the strumbot, which handles ...

That’s the gap between notes of the same name. For example, play an A note on your guitar, and the gap either up or down the fretboard to the next A note is an octave. That next A along will be ...