Breadboard FFT Guitar Tuner
Nikodem Bartnik’s pocket-sized tuner works with guitars and ukuleles!
When playing the guitar, Nikodem Bartnik uses a tuner to keep things... in tune. To most musicians, a guitar tuner is a pretty standard piece of equipment that just works, and likely not something that's given much further thought. This, however, wasn’t good enough for Bartnik, who wanted to understand it further and built his own!
He started prototyping the device with a Seeed Studio Grove Beginner Kit, creating a breadboard circuit that uses a fast Fourier transform (FFT) to resolve different frequencies. With this knowledge in-hand, as well as the open source amplifier circuit from the Grove board, he was able to transfer this functionality over to a PCB design.
The result is a very small unit that would be easy to stuff in your guitar bag or pocket for mobile tuning. It runs for around 10 hours on a single CR2032 battery, and with a bit different resistor setup, could probably be used for much longer if needed. As an extra bonus, it can be used to tune a ukulele, by holding down the device’s button. It lights up four LEDs when switched to signify the little instrument's four strings.
Be sure to check it out in the video below, where you can see his guitar skills on display in a few short bursts. He also shares his experience using a solder paste stencil for the first time, which would be helpful for those contemplating such a labor saving tool!