Capacitive sensor

Touch less - respons without pressure or touch

Further development of capacitive touch-sensitive switches has resulted in so-called touch less sensors or proximity switches. These sensors detect the mere close approach to the sensor surface. Direct contact is therefore no longer necessary.

Therefore, capacitive sensors are ideally suited for applications with strict hygiene regulations or with required protection against vandalism. The touchless sensor can be mounted out of view behind non-conductive surfaces such as glass, plastic, tiles, stone, ceramic, wood, textiles or wallpaper.

How does it work?

Capacitive proximity switches operate based on a similar principle as touch-sensitive capacitive controls or touch screens. As one approaches a proximity switch with a hand, an electric charge is extracted from the circuit. The evaluation electronics detect the change and trigger the appropriate function.

An application might, for example, switch from stand by to operating mode, when the capacitive sensor is approached. Mechanical switches and buttons can be replaced by electronic solutions, thus contact is no longer required.

Pros and cons

Pros

  • Clean and hygienic solutions due to non-contact operation
  • Increased comfort
  • Can be used for energy efficient applications
  • Robust with only minor wear and tear
  • Suited for input units exposed to high-risk of vandalism
  • Ideal for visually high-quality applications

Cons

  • Electromagnetic fields as well as moisture and temperature fluctuations may cause malfunctions.
  • The greater the detection range, the more susceptible the sensor will be to malfunctions.

Applications

Capacitive proximity switches promote energy efficiency. For example, those devices with higher energy consumption such as screens can switch to standby mode earlier. Additionally increasing ease of use, a device can detect when an operator is approaching and automatically switch to operating mode before contact is made.

Among others, capacitive proximity switches are now used in the following areas:

  • Applications with high quality surface designs (switching lights on/off, opening drawers)
  • Applications with strict hygiene requirements (touchless operation)
  • Industrial PCs
  • Input devices in the public sector