Accurate mechanocardiogram sensors using amorphous star-shaped core multivibrator combined with a magnet

New non-contact type accurate mechanocar-diogram sensors are presented using an amorphous star-shaped core multivibrator combined with a small magnet. These sensors can detect magnet displacement from 0.02 μm to 15 mm. Accurate mechanocardiograms (heartbeat cardiogram, phonocardiogram, and blood-vessel pulsation) are stably detected by fixing a small magnet on the chest wall or the blood-vessel position. A prototype sensor is fablicated with a microchipped multivibrator circuit and a filter which uses a 3 volts and 9 mA power source.