Making Waves: print out sound waves with the Raspberry Pi

For fun, Eunice Lee, Matthew Zhang, and Bomani McClendon have worked together to create Waves, an audiovisual project that records people’s spoken responses to personal questions and prints them in the form of a sound wave as a gift for being truthful.

Waves

Waves is a Raspberry Pi project centered around transforming the transience of the spoken word into something concrete and physical. In our setup, a user presses a button corresponding to an intimate question (ex: what’s your motto?) and answers it into a microphone while pressing down on the button.

What are you grateful for?

“I’m grateful for finishing this project,” admits maker Eunice Lee as she presses a button and speaks into the microphone that is part of the Waves project build. After a brief moment, her confession appears on receipt paper as a waveform, and she grins toward the camera, happy with the final piece.

Eunice testing Waves

Waves is a Raspberry Pi project centered around transforming the transience of the spoken word into something concrete and physical. In our setup, a user presses a button corresponding to an intimate question (ex: what’s your motto?) and answers it into a microphone while pressing down on the button.

Sound wave machine

Alongside a Raspberry Pi 3, the Waves device is comprised of four tactile buttons, a standard USB microphone, and a thermal receipt printer. This type of printer has become easily available for the maker movement from suppliers such as Adafruit and Pimoroni.

Eunice Lee, Matthew Zhang, Bomani McClendon - Sound Wave Raspberry Pi

Definitely more fun than a polygraph test

The trio designed four colour-coded cards that represent four questions, each of which has a matching button on the breadboard. Press the button that belongs to the question to be answered, and Python code directs the Pi to record audio via the microphone. Releasing the button stops the audio recording. “Once the recording has been saved, the script viz.py is launched,” explains Lee. “This script takes the audio file and, using Python matplotlib magic, turns it into a nice little waveform image.”

From there, the Raspberry Pi instructs the thermal printer to produce a printout of the sound wave image along with the question.

Making for fun

Eunice, Bomani, and Matt, students of design and computer science at Northwestern University in Illinois, built Waves as a side project. They wanted to make something at the intersection of art and technology and were motivated by the pure joy of creating.

Eunice Lee, Matthew Zhang, Bomani McClendon - Sound Wave Raspberry Pi

Making makes people happy

They have noted improvements that can be made to increase the scope of their sound wave project. We hope to see many more interesting builds from these three, and in the meantime we invite you all to look up their code on Eunice’s GitHub to create your own Waves at home.