Web Site: www.parallax.com Office: (916) 624-8333 Forums: forums.parallax.com Fax: (916) 624-8003 Sales: sales parallax.com Sales: (888) 512-1024 Technical: support parallax.com Tech Support: (888) 997-8267 PIR Sensor ( 555-28027) The PIR (Passive Infra-Red) Sensor is a pyroelectric device that detects motion by sensing changes in the infrared (radiant heat) levels emitted by surrounding objects. This motion can be detected by checking for a sudden change in the surrounding IR pattern. When motion is detected the PIR sensor outputs a high signal on its output pin. This logic signal can be read by a microcontroller or used to drive an external load see the source current limits in the features list below. NOTE: Revision B of this sensor provides many updates and improvements from Revision A. If your PIR Sensors PCB does not read Rev B, please use the information found in the Revision History section on page 5. Features Detect a person up to approximately 30 ft away, or up to 15 ft away in reduced sensitivity mode Jumper selects normal operation or reduced sensitivity Source current up to 12 mA 3 V, 23 mA 5 V Onboard LEDs light up the lens for fast visual feedback when movement is detected Mounting holes for 2 sized screws 3-pin SIP header ready for breadboard or through-hole projects Small size makes it easy to conceal Easy interface to any microcontroller Key Specifications Power Requirements: 3 to 6 VDC 130 A idle, 3 mA active (no load) Communication: Single bit high/low output Operating temperature: 32 to 122 F (0 to 50 C) Dimensions: 1.41 x 1.0 x 0.8 in (35.8 x 25.4 x 20.3 cm) Application Ideas Motion-activated nightlight Alarm systems Holiday animated props Copyright Parallax Inc. PIR Sensor ( 555-28027) v2.2 6/13/2012 Page 1 of 5 Theory of Operation Pyroelectric devices, such as the PIR sensor, have elements made of a crystalline material that generates an electric charge when exposed to infrared energy. The changes in the amount of infrared energy striking the element change the voltages generated, which are measured by an on-board amplifier. The device contains a Fresnel lens, which focuses the infrared signals onto the element. As the ambient infrared signals change rapidly, the on-board amplifier trips the output to indicate motion. The onboard jumper allows the user to select between normal operation and reduced sensitivity. The sensitivity of the PIR Sensor varies with temperature and other environmental conditions. Generally, when in reduced sensitivity mode, the PIR sensor will detect an object at up to half the distance it would in normal operating mode. For more information, see the Range section below. Range The PIR Sensors range is affected by: The sensitivity jumper setting The size and thermal properties of nearby objects Environmental conditions including ambient temperature and light sources The graph below depicts the approximate effects of known ambient temperatures on the PIR Sensors detection range of an average adult. The graph below depicts the approximate effects of known temperatures on the PIR Sensors detection range of an adult. Note: This device is designed for indoor use. Operation outside or in extreme temperatures may negatively affect stability. Direct exposure to sunlight or other forms of radiant heating may cause undesired operation. Copyright Parallax Inc. PIR Sensor ( 555-28027) v2.2 6/13/2012 Page 2 of 5