Like millions of other people, Wanda Diaz Merced plans to observe the August 21 total solar eclipse, when the moon’s shadow will sweep across the sun and, for a few brief moments, coat parts of the United States in darkness. But she won’t see it. She’ll hear it.
Diaz Merced, an astrophysicist, is blind, with just 3 percent of peripheral vision in her right eye, and none in her left. She has been working with a team at Harvard University to develop a program that will convert sunlight into sound, allowing her to hear the solar eclipse. The sound will be generated in real time, changing as the dark silhouette of the moon appears over the face of the bright sun, blocking its light. Diaz Merced will listen in real time, too—with her students at the Athlone School for the Blind in Cape Town, South Africa, where she teaches astronomy.
“It’s an experience of a lifetime, and they deserve the opportunity,” Diaz Merced said.
To capture the auditory version of this astronomical event, the team turned to a piece of technology measuring only a couple inches long: the Arduino, a cheap microcomputer popular with tech-savvy, DIY hobbyists. With a few attachments, Arduinos can be used to create all kinds of electronic devices that interact with the physical world, from the useful, like finger scanners that unlock garage doors, to the silly, like motion-detecting squirt guns. Diaz Merced’s collaborators equipped an Arduino with a light-detecting sensor and speaker, and programmed it to convert light into a clicking noise. The pace of the clicks varies with the intensity of the sunlight hitting the sensor, speeding up as it strengthens and slowing down as it dims. In the moments of totality, when the sun’s outer atmosphere appears as a thin ring around the shadow of the moon, the clicks will be a second or more apart.