Can we use Pyroelectric infrared sensor outside?
Yes, they can be used outside.
However, when the sensor is used outside, since there are many factors which generate a thermal change, it is more difficult to use the sensor outside than inside.
When sunlight and wind directly contact the sensor, an output may occur by reacting to the change in temperature caused by such factors.
Install the sensor in a location where there is no direct contact from sunlight and wind, and where there is no condensation.