Adafruit PIR_Motion_Sensor
The sensor in a motion detector is actually split in two halves. The reason for that is that we are looking to detect motion (change) not average IR levels.| Part No. | PIR_Motion_Sensor |
|---|---|
| Datasheet | PIR_Motion_Sensor Download |
| Manufacturer | Adafruit |
| Description | PIR Motion Sensor |
| Buy | Stock & Price |
PIR Motion Sensor Created by lady ada Last updated on 2020-01-25 05:57:43 PM UTC Overview PIR sensors allow you to sense motion, almost always used to detect whether a human has moved in or out of the sensors range. They are small, inexpensive, low-power, easy to use and don't wear out. For that reason they are commonly found in appliances and gadgets used in homes or businesses. They are often referred to as PIR, "Passive Infrared", "Pyroelectric", or "IR motion" sensors. PIRs are basically made of a pyroelectric sensor ( (which you can see below as the round metal can with a rectangular crystal in the center), which can detect levels of infrared radiation. Everything emits some low level radiation, and the hotter something is, the more radiation is emitted. The two halves are wired up so that they cancel each other out. If one half sees more or less IR radiation than the other, the output will swing high or low. Along with the pyroelectic sensor is a bunch of supporting circuitry, resistors and capacitors.
