A proximity sensor for the detection of hands on a steering wheel

An embedded coax proximity sensor for the detection of hands or other objects near a vehicle's steering wheel

The Need

The coming age of autonomous vehicles will require the development of many new technologies to keep the vehicle occupants safe even when no one is paying attention to the vehicle operation. At present, given the limited capabilities of autonomous vehicles, it is necessary for the driver to monitor the vehicle and take over driving in a split second. One way for the vehicle to recognize that the driver can take over control of the vehicle is to determine if the driver has his or her hands on the steering wheel. The location of the hands is also important to determine how attentive the driver is.

The primary hand sensor on the market is based on a capacitive sensor system similar to the sensor currently used in touchscreens. The disadvantage of this approach is that the sensitivity of the system is dependent on the electrical characteristics of the hand which may vary with individuals and even vary with a single individual based on the environment (e.g. dry versus humid). Also, if the driver is wearing gloves, the capacitive sensor may not work well. A second issue with the market technology is the electronic complexity associated with the sensor, which has a large footprint that makes it not feasible for use in a vehicle steering wheel. Thus, there is a need for a compact and universal sensor usable in a variety of conditions.

The Technology

A team of researchers at The Ohio State University led by Dr. Robert Lee and Dr. Asimina Kiourti has developed a novel sensor for detecting hands on or near a steering wheel. The coax proximity sensor developed can detect the presence and/or position of any possible object, especially those with large permittivity or conductivity, like human tissue, on the sensor. This sensor can be embedded into the steering wheel. Because the coaxial line is only partially shielded, the presence of a hand close to the coaxial line will affect the signal traveling through along the line. From the signal, one can determine the distance between the hand and the coaxial line as well as the location of the hand(s) on the steering wheel.


  • Driver assisted systems
  • Autonomous systems


  • Differences in hand properties do not significantly affect sensor: no need for calibration
  • Gloves or other hand coverings can be worn
  • Can detect the location of hand(s)
  • May be able to distinguish hand from other objects
  • Electronics needed for the sensor can be miniaturized.

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