A mount for the commonly used 18mm barrel infrared sensor that can be purchased from Amazon. I designed two options for the mount. One is threaded so you will only need one jam nut to lock the sensor in place and the other is a through hole so two jam nuts will be required. The mounting holes are sized for #10 screws and have two hole spacing options: A 1.5in center distance and a 1.414in center distance. The 1.414in center is designed to be mounted to 2x1 tubing using diagonal holes on a 1in x 1in grid. 

Link to purchase sensor: E18-D80NK