A number of different types of sensors can be used as Entry/Exit Sensors. Here are some recommendations.
The best Entry/Exit sensor is the Acuity 47 located in the door jam above the door. It works extremely well and it is almost completely inconspicuous. However, it will likely pick up dogs and cats as well as people.
The Acuity 47 in a ceiling of less than 8 feet also works very well. The sensor should be located in the room, not in the hallway.
The Acuity 47 in the door jam at dead bolt height also works very well, and dogs and cats will walk under it.
The Acuity 47 does not work as well one foot off the floor. Apparently, baggy pants can mask the change in heat of someone walking by. That is to say, the sensor may only work 95% of the time. However, it does seem to work better at three inches above the floor.
We've also had success with the Sure Action Pulsor - a set of 3 stress sensors connected under the floor of the door or under the first or last step of a set of stairs.
We have not been as successful with the indoor beam sensors across doorways, and they are more difficult to install and service. However, a high quality one such as the Takex (formerly Pulnix) PB-IN-75SW Photoelectric Beam Sensors may work indoors to create two smaller rooms out of one large room.
We do not recommend using contact sensors as Entry/Exit sensors because if the door remains open they do not work as an Entry/Exit sensor.
Outdoors, we recommend using the best quality long-range beam sensors such as the Takex (formerly Pulnix) PB-IN-75SW Photoelectric Beam Sensors. These should be placed across driveways and walkways at the edge of the property and between two different areas of the property to separate it into "Rooms", also.