Hand Grip Sensing on the Steering Wheel by a Layered Velostat and Silver-Based Textile Sensor

This paper presents the design and experimental characterization of an unobtrusive, low-cost layered sensor for hand grip detection on a steering wheel. The sensor is composed of multiple layers of piezoresistive Velostat film sandwiched between two flexible electrodes made of 99% silver-based conductive fabric. Experimental tests were conducted in the time domain to evaluate the sensor's performance under various pressure conditions and mounting configurations. The results indicate that the sensor resistance drops significantly, by a factor of approximately 2.4, when a force of around 1N is applied, facilitating reliable detection of the driver's grip. Furthermore, preliminary data suggest that the magnitude of resistance variation correlates with the hand's position on the sensor, offering a potential pathway for identifying hand placement on the steering wheel, to be investigated in future works. Impedance analysis revealed a band-pass behavior in the 20kHz to 200kHz range, which remains consistent after installation on the wheel. These findings demonstrate the feasibility of using Velostat-textile composites for non-intrusive driver monitoring systems.