min is an electronic musical instrument prototype inspired by the theremin. A theremin is an instrument that uses the position of the musician's hand to determine the pitch of the sound emitted. Min is a minimalistic implementation of that, comprised of an ultrasonic sensor, a buzzer, and an Arduino Uno board.

What it does

Like a theremin, min uses the distance of the player's hand to determine the frequency of the tone. The distance is measured with an ultrasonic sensor and is then mapped to a specific frequency corresponding to a note on the musical scale. For example, middle C (C3) is 262 Hz. The further away from the ultrasonic sensor the player's hand is, the higher pitched the tone is. Information about the tone played, including distance, frequency, and name, is displayed on an LCD. The note range can be transposed and the play mode can be switched from slide to button mode by remote.

How I built it

min is built with an Arduino kit supplied Technica 2020, the Arduino IDE, and C++.

Challenges I ran into

min is my first foray into hardware. Initially, I was concerned I wouldn't be able to build much without an electrical engineering background, but basic knowledge of circuits seemed to suffice. The ultrasonic sensor wasn't accurate in its distance measurements if it wasn't obstructed by an object with a flat face. The Uno board has a flash memory of only 32,768 bytes (minus 0.5kB used for the boot loader program)!! Since I mostly work with high-level languages like JavaScript in VS Code, returning to a low-level language like C++ on a barebones IDE was a bit of a shock (I missed auto-formatters).

Accomplishments that I'm proud of

I built something! With my two hands!

What I learned

Arduino libraries are a lifesaver.

What's next for min

In its current state, min only supports monophonic play (melody without harmony). An additional sensor can be added to support a harmonic line.

Shout out to Xinquan Tian for mentorship.

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