Check the listing for details. 1PCS New HC-SR501 Infrared PIR Motion Sensor Module for Arduino Raspberry. Listed at 1.99 USD. The product is a new HC-SR501 Infrared PIR Motion Sensor Module designed for use with Arduino and Raspberry devices. This sensor module detects motion by sensing changes in the infrared radiation pattern in its field of view, making it ideal for applications where detecting movement is important. With its compact size and easy integration with various microcontrollers, this sensor module is a versatile and cost-effective option for robotics, home automation, and security systems, among other potential uses.