Our friend Arjan van der Meij made this charming musical instrument from a signal generator, a servo motor, an Arduino and a processing program. He wrote an instructable for it so you can build one, too.
He also wrote about his experience with the project in Dutch on makered.nl. Projects like this one, that started with a question (“Why don’t you build a machine to do it?”) are great for learning new skills. I often get asked what things someone should get for learning electronics, and my answer is usually that the first thing you need is a project that you want to make so that you’ll have motivation to research what you’ll need.
Arjan wanted to learn tinkercad, and used this project toward that goal by modeling the knob adapter he’d need for connecting his servo to his signal generator knob. Even if you don’t want to make a musical instrument from a signal generator, this project may provide inspiration for trying out new techniques.