Here are more pictures. Sorry that the pictures are rotated. All parts are from Lowe’s. I decided to just use masking tape across the sprinkler pipe where it enters the electrical box hole. Just wrapped the tape until inserting the tube into the box was snug to prevent water going in. The sprinkler pipe is pushed in until it rests on the motion sensor and it is centered over the sensor. Cut the tube to the length your want to eliminate false alarms. Mine is about 3 inches. I drilled some holes in the bottom of the electrical box so it has some breathing room since the temperature can get up to 105 degrees.
