David Usher's "HEARTBEAT" device
A musician David Usher and his team from Foulab in Montreal created a device that converts heartbeats into midi signals and engages audience into performance.
David Usher is an outstanding figure. He is a world-famous artist, best-selling author, entrepreneur and keynote speaker. David has sold more than 1.4 million albums worldwide, had 10 No. 1 songs on Canadian radio, and won five Juno awards.
He is passionate about new technologies and their application to art and media. His company, Human Impact Lab brings together artists, designers and programmers to work on a vast range of innovative projects.
One of their projects is called “HEARTBEAT”. The initial inspiration came to David while he was thinking about the dynamics of the concert and possible ways to engage audience into a creative process. “How could we get the audience to power the band?” he asked. Curiosity and desire to experiment with technology forced his team to start looking for an answer to that question.
This is how an idea of a heartbeat to midi device, that can read a person heartbeat and produce a midi note, was born. Usher contacted Rupert Brooks from FouLabs in Montreal, and they had embarked on a long journey of testing different heart rate monitors, building customized circuit boards and writing algorithms.
While simple in principle, the tricky part is that the human heartbeat is actually fairly irregular and the ear picks up this irregularity very quickly. To make this work in an aesthetically pleasing way, it was necessary to smooth out the rate, but remain reasonably responsive to changes in heart rate. Simple linear filtering was not enough, and an adaptive algorithm had to be developed. The heart beat rate must fall on one of a set of stable rates, and, it must not change back and forth between these rates too rapidly. Rupert chose multiples of 5bpm. There is also hysteresis in the changing between these rates. To change from one rate to another, the computed interbeat delay is averaged over the last 12 beats and must move more than 80% of the way to the next BPM rate before the switch is made. The code for the project is available on GitHub: https://github.com/str4w/HeartbeatMidi
In the beginning Rupert tried using various boards, but eventually he switched to Arduino Nano and 9V instead of AA batteries purely for space reasons, so the whole thing fit in an Altoids tin. Two LED's were placed on the box - one to indicate detection of the heartbeat, and one to indicate the output of the note.
It took them around 8 months to complete and in 2013 the project was finished. Since then, at concerts, David Usher and his band always use the “HEARTBEAT” with their fans. Inspired by the pulse of their fans, the musicians improvise new songs and give joy to the audience.