Resistive Versus Capacitive


Resistive sensor interface solutions  use pressure sensitivity to activate and enable user controls. As such, they are passive components, requiring no dedicated microprocessor and only minimal battery power. See how this compares with capacitive controls.

 

FSR

Capacitive

External microprocessor
  • No ASIC or microprocessor required
  • FSR connected to host processor
  • Saves cost, space and battery life
  • Required
  • Contributes to cost and power consumption
  • Requires extra space (5.5 x 5.5 x 1.0 mm min.)

Enhanced capabilities

  • Force sensing provides enhanced scrolling

  • Not a force sensor

Power Consumption
  • No dedicated processor required
  • No power required in untouched state
  • Average measurement current <20 ľA
  • Measurement requires 1000 ľA
  • Sleep mode requires 70 ľA

Activation

  • Finger, stylus, actuator, gloved finger

  • Requires direct skin contact

Mechanical
  • Thickness as low as 0.012 inch (0.30 mm)
  • Surface contaminants do not affect operation
  • Long life – over 2 million actuations
  • Thickness of 2.5 mm or greater
  • Water and other contaminants can impact performance

Cost

  • Low cost, no microprocessor required, high volume production process

  • Higher cost from dedicated microprocessor, some suppliers require complete module purchase

Notes

  • Available options include PCB assembly, narrow tail pitch, EL and LED lighting, metallic actuators, PC over silicone actuators

  • Inadvertent actuations a nuisance; some suppliers leave customer to design, procure and integrate sensor