HC-SR501 PIR Motion Sensor Module - Infrared Human Detection, Adjustable Delay and Sensitivity, for Arduino and Raspberry Pi DIY Projects

The HC-SR501 PIR Motion Sensor Module is an essential component for makers, engineers, and hobbyists looking to incorporate human presence detection into their electronics projects. Utilizing passive infrared technology, this sensor detects motion by sensing changes in infrared radiation emitted by surrounding warm bodies. Whether you are designing an automated lighting system, an intrusion alarm, or a smart home monitoring array, the HC-SR501 delivers reliable performance and flexible configuration options. Its robust design and wide compatibility make it a staple in the DIY electronics and microcontroller community.

At the core of the module is a pyroelectric sensor covered by a specialized Fresnel lens, which focuses infrared energy onto the sensing element. The onboard BISS0001 IC processes the signals received from the sensor, providing a stable digital output when motion is detected. The module features two user-adjustable potentiometers: one for adjusting the sensing distance from approximately three to seven meters, and another for setting the output signal hold time from a few seconds to several minutes. Additionally, a jumper selection allows users to toggle between two trigger modes: single-trigger mode, which yields a single pulse per detection event, and repeatable-trigger mode, which continuously resets the output timer as long as motion persists.

Operating voltage ranges from DC 4.5V to 20V, with a very low quiescent current draw. The digital output signal provides a high level of 3.3V and a low level of 0V, ensuring direct compatibility with 3.3V and 5V logic inputs on popular development boards. The standard detection angle spans a cone of approximately 100 degrees, covering a generous field of view. The sensing distance is manually adjustable, spanning a range of 3 to 7 meters depending on ambient temperature and lens configuration. The operating temperature range accommodates standard indoor environmental conditions.

This motion sensor module is perfectly suited for a wide array of DIY projects, including automated corridor lights, burglar alarms, visitor counters, robotics obstacle or presence detection, and interactive art installations. It integrates seamlessly with microcontroller platforms such as Arduino, ESP32, and Raspberry Pi, enabling smart automation scripts that respond dynamically to human activity in the room.

When integrating the HC-SR501 into your circuit, ensure that the power supply matches the specified voltage range. Allow a warm-up period of approximately one minute upon initial power-up for the pyroelectric sensor to stabilize and calibrate to the ambient environment. Position the sensor away from direct sunlight, heating vents, and air conditioning units to prevent false triggering caused by rapid temperature fluctuations or air drafts. Connect the VCC, Output, and Ground pins directly to your microcontroller or power bus using standard female-to-male jumper wires.

1x HC-SR501 PIR Motion Sensor Module