Monday, November 14, 2011

X-Band Motion Detector by Parallax

The X-Band Motion Detector is a common ingredient in security systems and automatic door openers, and can detect movements in a room, yard, or even on the other side of a wall. It’s a Doppler radar sensor that operates in the X-band frequency at 10.525 GHz, and indicates movements with oscillations in its high/low output. Sensitivity is manually adjustable with a potentiometer on the back of the device, offering direct line of sight detection from roughly 8 to slightly over 30 ft (~2.4 to 9+ m).


  • Operation frequency of 10.525 GHz
  • Able to detect motion through walls and windows
  • More immune to false triggers than passive infrared motion sensors
  • Active-high enable pin with internal pull-up resistor
  • Trim potentiometer on the back for manually adjustable sensitivity
  • 4-Pin SIP header for breadboard or through-hole prototyping
  • Built-in series resistor for compatibility with the Propeller microcontroller and other 3.3 V devices
  • Plated test point hole for monitoring pre-comparator signal

Key Specifications

  • Power supply requirements: regulated 5 VDC, 8 mA
  • Communication: High (3.9 V) / low (0 V) signal oscillates with motion
  • Dimensions: 1.83 x 1.87 x 0.69 in (46.5 x 47.5 x 17.6 mm)
  • Operating temp range: 32 to 131 °F (0 to 55 °C)

Application Ideas

  • Security systems
  • Automatic door openers
  • Automatic lighting
  • Nuisance animal deterrence