Getting past a motion sensor can be tricky, but with an understanding of what areas they are designed to cover and their specific placement in a room, you can keep from setting them off without much trouble at all. Even though most motion sensors are designed to be very responsive to the movement in a room, they rarely have the capability to detect movement in every single place in the room. Once you know how to bypass setting them off, you can avoid waking up your family in the middle of the night.
Do not move at all once you realize that you need to bypass a sensor. Evaluating the area first is beneficial to understanding the environment around the sensor and determining what paths may be taken to bypass it.
Look for the location(s) of any motion sensors around you. Sensors are usually placed on ceilings or directly across from each other to cover a larger area. Once you see where they are located, you will be able to determine a possible path around their field of vision.
Move slowly along the walls in which the sensors are located, and as low as possible, while proceeding forward. Many motion sensors have blind spots that make it difficult to detect movement directly underneath them. Be aware that another sensor may be pointing in your direction from the other side of the room.
Get on your knees and crawl through any open spaces or in front of big pieces of furniture. Most motion detectors are calibrated in a way to make them pet-friendly, so try to stay as low as the average dog would be while moving through the room. Motion detectors are commonly configured to allow animals to move freely throughout the house without setting off any alarms.
Block the sensors with a piece of paper or cardboard. This will not work for all motion sensors, but it can be attempted in cases where there may not be very much room free from their line of sight. Place the paper or cardboard in front of the sensors very slowly, then attach it to the unit before proceeding.