PIR Sensor SR501

HC-SR501 PIR Motion Sensor Module

Features:

• Motion Detection: Utilizes a pyroelectric sensor to detect motion by measuring changes in infrared radiation levels.​
• Adjustable Sensitivity and Delay: Features two variable resistors to fine-tune sensitivity and output delay time.​
• Low Power Consumption: Operates efficiently with minimal energy usage, suitable for battery-powered applications.​
• Easy Integration: Compatible with various microcontrollers like Arduino, Raspberry Pi, and others, facilitating straightforward integration into projects.

Specifications:

• Supply voltage of  DC: 4.5 V to 20 V
• Power consumption in standby mode: 50 uA
• Output voltage: 3,3 V
• Measuring range: max. 7M
• Viewing angle: up to 120 °
• Digital output:
  • High status – object detected
  • Low status – no object
• The dimensions of the base of module: 33 x 24 mm
• Bowl diameter: 23 mm
• Bowl height: 18 mm
• Total height: 25 mm (with elements mounted in the bottom of the board)

The digital output allows connection of the sensor to any board equipped with a microcontroller, e.g.Arduino, STM32 Discovery or minicomputer Raspberry Pi. Pins are gold pin connectors (pitch of 2.45 mm) for connecting the sensor by wires.

Thanks to a potentiometer, the user can adjust:

• T1– duration of the high state upon detection of the object
• T2– sensor sensitivity (distance, which detects the movement of an object)

With the jumper, which has to be self-soldered, mode of operation is selected from two available outputs:

• retriggering (jumper in H position) – the output reaches a high status, after the detection of the object and it is held for the entire time of detection of continued motion,the sensor, by default, is in this mode (no jumper)

• non-retriggering (jumper in position L) – the output reaches a high status only once, after detection of the object and then goes to a low status, regardless of whether the movement continues

Module Connections:

There is a 3-pin header on the assembly.  The markings are hidden by the plastic dome, so refer to the picture for the pin-out.  The dome can also be easily removed to see the markings.

1 x 3 Header:

• VCC =   Connect to 4.5V to 20V
• OUTPUT =  Digital sensor output (active HIGH) – Normally connects to a digital input pin on a uC
• GND =  Connect to system ground.  This ground needs to be in common with the uC

Applications:

• Security Systems: Detects unauthorized movement in surveillance areas.​
• Lighting Control: Automates lighting systems by activating lights upon detecting motion
• Automation Projects: Integrates into various automation systems requiring motion sensing capabilities.​
• Robotics: Enables robots to sense human presence or movement in their environment.