A team of students at Johns Hopkins' Whiting School of Engineering has designed a stethoscope for NASA that delivers accurate heart and body sounds to medics trying to assess astronauts' health on long missions in noisy spacecraft.
Space is serene because no air means no sound. But the inside of the average spacecraft—with its whirring fans, humming computers, and buzzing instruments—is about as raucous as a party filled with laughing, talking people.
"Imagine trying to get a clear stethoscope signal in an environment like that, where the ambient noise contaminates the faint heart signal. That is the problem we set out to solve," says recent graduate Elyse Edwards, who teamed up on the project with classmates Noah Dennis and Shin Shin Cheng.
The students worked under the guidance of James West, a research professor in Electrical and Computer Engineering and co-inventor of the electret microphone technology developed for telephones and used today in almost 90 percent of the more than 2 billion microphones produced each year.
Together, they devised a stethoscope that uses both electronic and mechanical strategies to help the device's internal microphone pick up sounds that are clear and discernible in the noisy spacecraft, even when the device is not placed perfectly correctly on the astronaut's body.
"Considering that during long space missions there is a pretty good chance an actual doctor won't be on board, we thought it was important that the stethoscope did its job well, even when an amateur was the one using it," Dennis says.
The device also includes many other improvements, including low power consumption, rechargeable batteries, mechanical exclusion of ambient noise, and a suction cup so that it sticks firmly onto the patient's chest, Cheng says.
The project was developed during a two-semester senior design course offered by the Whiting School's Department of Mechanical Engineering in which teams of three or four undergraduates are each given a small budget to design and build a prototype requested by a sponsoring business or organization.
Though developed for NASA's use in outer space, this stethoscope could also be put to use on Earth—in combat situations, where ambient noise is abundant, and in developing countries, where medical care conditions are primitive.
West plans to use the device to record the heart and lung sounds of infants in developing countries as part of a project to develop a stethoscope that knows how to identify the typical wheezing and crackling breath sounds associated with common diseases. This would allow on-site medics to make preliminary automated diagnoses.