PIR Motion Sensor HC-SR501

PIR Motion Sensor HC‑SR5​01 – Motion & Position Sensors
The HC‑SR501 is a compact, low‑cost passive infrared (PIR) sensor that detects the heat signatures of moving objects up to 7 m away. When a warm body passes through its 120° field of view, the sensor’s built‑in comparator triggers a digital HIGH output, making it ideal for Arduino, Raspberry Pi, or micro‑bit projects. Its adjustable sensitivity and delay‑time potentiometers let students fine‑tune detection range and response time without any soldering, giving them immediate, hands‑on feedback on how hardware parameters affect software behavior.

Working with the HC‑SR501 introduces learners to core STEAM concepts: electromagnetic radiation, signal processing, algorithmic decision‑making, and real‑world system integration. Students will design motion‑activated lights, security alarms, interactive art installations, and data‑logging devices, while exploring topics such as energy efficiency, human‑machine interaction, and the ethics of surveillance. Key features include a 3.3 V–5 V operating voltage, dual‑mode (single‑pulse or continuous) output, built‑in hysteresis for noise immunity, and a compact 16 × 24 mm footprint that fits neatly on any breadboard. Its simplicity and versatility make the HC‑SR501 a cornerstone sensor for any STEAM curriculum, empowering students to prototype, iterate, and bring dynamic, sensor‑driven ideas to life.