Description:

PIR sensors, often referred to as, "Passive Infrared" or "IR motion"  sensors, enable you to sense motion. Everything emits a small amount of  infrared radiation (IR), and the hotter something is, the more radiation  it emits. PIR sensors are able to detect a change in average IR levels  of their detection zone (e.g. when a human enters a room, that room will  increase in temperature slightly) and hence sense motion. 

This  one's great, as it can be powered  via the Raspberry Pi's 5V output, and  be read directly from the Raspberry Pi's GPIO input (as the sensor has a  digital 3.3V output!)

This PIR includes an adjustable delay  before firing (approx 0.5 - 200 seconds), has adjustable sensitivity and  two M2 mounting holes! It runs on 4.5V-20V power (or 3V by bypassing  the regulator with a bit of soldering) and has a digital signal output   (3.3V) high, 0V low. Its sensing range is up to 7 meters in a 100  degree cone.

Specifications:

• Input Voltage: 4.5V - 20V
• Current Draw: <50µA
• Digital Output: 3.3V (High)
• Digital Output: 0V (Low)
• Working Temperature: -15°C to 70°C
• Delay Time: 0.5 - 200 Seconds
• Sensing Angle: 100° Cone
• Range 5m - 7m

Dimensions:

• Sensor Lens Diameter: 23mm
• Length: 24.03mm
• Width: 32.34mm
• Height (with lens): 24.66mm
• Centre screw hole distance: 28mm
• Screw hole diameter: 2mm (M2)

Contents:

• 1x HC-SR501 Motion Sensor

Resources:

• PIR Sensors and the Raspberry Pi
• Python Library