Norwegian scientists at the SINTEF Telecom and Informatics laboratory have invented an earplug with a built-in computer that conveys speech but blocks out unwanted and harmful sounds.
The earplug, dubbed the Personal Active Radio/Audio Terminal (PARAT), contains a miniature loudspeaker and an inner and outer microphone.
The inner microphone measures noise in the ear. Initially, the earplugs block out all noise, but an electronic chip transmits selected sounds.
In quiet conditions, the earplug ‘opens up’ and the wearer is able to hear everything normally. However, as soon as PARAT registers significant noise, it shuts out unwanted sounds, and transmits only normal speech.
PARAT’s electronic circuitry is built into a tiny chip embedded in the earplug and is said to combine with a radio to provide a communication terminal for use in a noisy environment.
Vibrations from the voice of the user are transmitted to the inner microphone in the earplugs through the tissues of the head.
When PARAT is turned on, it first analyses the sound reaching the wearer’s ear, looking for voice signals. ‘It knows what areas of the spectrum voices are produced in, and it looks at the time variation and frequency content of the signal,’ explained Jarle Svean, senior researcher at SINTEF Telecom and Informatics.
The internal microphone is said to ensure that the loudspeaker’s volume is at a safe level, and also serves to pick up the wearer’s own voice through the ear canal.
To demonstrate the potential of the device, PARAT was tested at SINTEF Telecom and Informatics laboratory with powerful loudspeakers generating a cacophony of noise.
The researchers fitted a mobile phone with earplugs, which acted as a speaker for the caller and as a microphone for the phone user.
The researchers believed that a phone conversation would be impossible in these conditions but, with the help of the earplug connections, the voice of the caller could be easily heard by the user.
PARAT has also been designed so that it can home in on a single voice, shutting out the complaints directed to those of you who happened to forget Valentine’s Day.