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ProxSense® Capacitive Proximity & Touch Controllers

Azoteq offers Proximity and Touch controllers for a wide range of applications.

Azoteq's ProxSense® offers:

  • Sensitivity of 0.1fF – 100x more sensitive than competition
  • Signal to Noise ratio of 1000:1 (competition <30:1)
  • Only company that can provide robust proximity solutions
  • Integration – lower system cost
  • Robust – auto tuning of electrode, changing environment, water, grease & dust
  • Fundamental patents on proximity and touch wake up

Theory of Capacitive sensing

  • Capacitive sensors measure a change in capacitance (increase or decrease)
  • Human body, hand or finger acts as a capacitor
  • Proximity or touch by a human changes the capacitance of the system
  • Capacitance changes are small
  • Touch – 10 pico Farads
  • Close proximity – 1 pico Farads
  • Proximity – 50-100 femto Farads
  • Charge transfer – measures capacitance by transferring charge from sense electrode to internal capacitor
  • Inexpensive PCB pads to sense a touch or proximity event
  • No mechanical parts
  • Front panel materials – glass or polycarbonate
  • Buttons protected from harsh environments

Self Capacitance

  • Controller measures capacitance of the sense electrode relative to ground
  • One connection for each touch switch
  • Hand or finger adds capacitance to circuit

Mutual Capacitance

  • Controller measures capacitance between two sense electrodes
  • Two connections for each touch switch
  • Hand or finger subtracts capacitance from circuit
 Self Capacitance  Mutual Capacitance

SelfMutual

Azoteq has more than 39 patents issued and pending on capacitive sensors technology and the proximity and touch user interfaces.

Contact Azoteq for more information about capacitive proximity switches, download a datasheet, or request an evaluation kit today.

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