Trumpeted as the world's smallest pyroelectric infrared (PIR) sensor, the IRS-B210ST01-RI measures 5 mm x 4.7 mm x 2.4 mm. The component is also said to be the only surface-mount PIR sensor available on the market. It includes dual 0.85 mm x 1.2 mm electrodes with a field of vision of ±70º horizontal and ±50º vertical. Operating temperature range is -40°C to +70ºC and operating voltage in the range of 2V to 15V. Sample price is $1.88. MURATA ELECTRONICS NORTH AMERICA INC., Smyrna, GA. (770) 436-1300.