The Elecrow Crowtail – Mini PIR Motion Sensor 2.0 is a compact, efficient and cost‑effective motion‑detecting module designed for embedding into DIY electronics, IoT, robotics, alarm and automation systems. Using a PIR (Passive Infrared) sensor chip (S16‑L221D), it detects the infrared radiation changes caused by moving warm bodies (like humans or animals), converting these into digital signals for microcontrollers to act on (e.g., trigger an LED, send alert, switch on lights). This module features on‑board digital signal processing (DSP) and includes filters that provide high immunity to radio frequency interference (RFI) and noise, helping reduce false positives that many PIR sensors suffer from. It has low power consumption, making it suitable for battery operated systems. Its “crowtail” compatible interface simplifies connecting to Crowtail base shields or compatible microcontroller boards. With a compact form factor, it’s unobtrusive yet effective. The sensor’s detection range is over 2 meters under normal conditions (≈25°C), with sensitivity in the range of ~120‑530 µV output from the PIR chip. Its physical dimensions are about 20 × 20 × 18 mm. Common applications include intruder alarms, presence/occupancy detection, automating lights, or anything needing motion detection in a small space. Overall, it’s a reliable mini PIR motion sensor for projects seeking reliable motion detection without high cost or high power draw.