Development of electrolarynx with hands-free prosody control

The feasibility of using a motion sensor to replace a conventional electrolarynx(EL) user interface was explored. Forearm motion signals from MEMS accelerometer was used to provide on/off and pitch frequency control. The vibration device was placed against the throat using support bandage. Very small battery operated ARM-based control unit was developed and placed on the wrist. The control unit has a function to convert the tilt angle into the pitch frequency, as well as the device enable/disable function and pitch range adjustment function. As for the forearm tilt angle to pitch frequency conversion, two different conversion methods, linear mapping method and F0 template-based method, were investigated. A perceptual evaluation, with two well-trained normal speakers and ten subjects, was performed. Results of the evaluation study showed that both methods were able to produce better speech quality in terms of the naturalness.