Touched by your presence

Switches and buttons have design constraints such as having to cope with a wide range of temperatures and humidity plus constant contamination from users. Not only are there far more switches and buttons in contemporary car design, but they also have to be installed into increasingly more contoured control surfaces. They must be cost effective, which rules out the use of hermetically sealed switches. One increasingly popular approach is the use of capacitive touch switches (cap sense). With no mechanical parts, plus the ability to conform to contoured surfaces, cap sense switches provide the reliability and cost effectiveness required by the industry. The switch is finger activated responding to the conductivity in the finger. The author explains the technical process including the mathematical equations involved and illustrates different parts of the process in diagrams. Because capacitive sensors have no mechanical parts, they can be placed on previously unused spaces such as the front of the steering wheel, or on window space. The sensors could also have security applications, such as the ability to send information to the owner's mobile phone, about inappropriate attempts to open the car door.


  • English

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Filing Info

  • Accession Number: 01109246
  • Record Type: Publication
  • Source Agency: Transport Research Laboratory
  • Files: ITRD
  • Created Date: Aug 25 2008 7:57AM