TRW Unveils Proximity Horn Button

Steering wheel architecture could be simplified by replacing the usual mechanical horn button mechanism with a directional proximity sensor, says TRW Automotive Holdings Corp.

The company is working on capacitive technology that sounds the horn through a sensitive conductive coating over the entire steering wheel airbag cover. The coating is linked to a fixed sensor and requires no pressure to activate.

TRW says its system can be "tuned" with smaller sensor fields to prevent the horn from being activated accidentally. Such fields could, for example, detect the difference between fingers accidentally brushing across the face of the steering wheel and a hand purposely approaching directly from the front.

TRW points out that switching to an electronic system would improve airbag mounting by eliminating the moving parts and cost and bulk of springs, contacts and clips required in mechanical horn buttons.

The company predicts the technology will be ready for production by 2014 and says "several" carmakers are interested.