The HC-SR501 PIR Motion Sensor Module detects human and animal movement using infrared sensing, with an adjustable 3–7m detection range and 5–200s delay. Operating at 4.5V–20V, it provides a digital HIGH/LOW output and low power consumption. Ideal for security systems, automatic lighting, robotics, Arduino, ESP32, and Raspberry Pi projects.

The Piezoelectric Knock Vibration Sensor Switch Module detects knocks, taps, vibrations, and impacts with adjustable sensitivity. It provides both digital TTL and analog outputs for easy integration with Arduino, ESP32, Raspberry Pi, and other microcontrollers. Featuring an onboard LED indicator and compact design, it is ideal for security systems, alarms, automation, robotics, and DIY electronics projects.