Medical sensor is powered by music

A new type of miniature pressure sensor designed to be implanted in the body is powered by acoustic waves from music. Credit: Birck Nanotechnology Center, Purdue University)= 

WEST LAFAYETTE, Ind., Jan. 26 (UPI) -- A new type of implantable medical sensor can be powered by external sounds like music -- and rap music works best, its U.S. inventors say.

Researchers at Purdue University say the miniature medical sensor is powered by acoustic waves, including those found in music such as rap, blues, jazz and rock.

The sensor contains a vibrating cantilever, a thin beam attached at one end like a miniature diving board. Music within a certain range of frequencies, from 200-500 hertz, causes the cantilever to vibrate, generating electricity and storing a charge in a capacitor, Purdue engineering professor Babak Ziaie said in a university release Thursday.

"The music reaches the correct frequency only at certain times, for example, when there is a strong bass component," he said. "The acoustic energy from the music can pass through body tissue, causing the cantilever to vibrate."

When the music stops or the frequency falls outside of the proper range, the cantilever stops vibrating, automatically sending the electrical charge to the sensor, which takes a pressure reading and transmits data as radio signals.

"You would only need to do this for a couple of minutes every hour or so to monitor either blood pressure or pressure of urine in the bladder," Ziaie said. "It doesn't take long to do the measurement."

Playing simple tones within a certain frequency range also can be used.

"But a plain tone is a very annoying sound," Ziaie said. "We thought it would be novel and also more aesthetically pleasing to use music."

"Rap is the best because it contains a lot of low frequency sound, notably the bass," Ziaie said.