Protection of wide-range QCR load sensor using robust outer case for stable detection of biosignals

We present a super wide-measurement range load sensor with high-durability for multi-biosignal sensing in daily life. We employed quartz crystal resonator (QCR) load sensor with super wide range (from 6 × 10^-5 to 30 [N]) for sensing of biosignals ranging from mN order (e.g. heartbeat) to 100 N order (e.g. body motion). Furthermore, we implemented an outer case which makes the sensor durable against unexpected loads in practical use. The outer case increased the durability of the sensor 88 times higher than the sensor without outer case. Finally we succeeded in simultaneous sensing of heartbeat (≈ 100 [mN]) and body motion (≈ 25 [N]) with identical sensor.