Useful for robotics, interactive media, industrial assembly line, etc. The infrared wavelength is part of the Sun's natural light spectrum. While is a nice fit for indoor projects, outdoors with plenty of sunlight and reflective surfaces on its sight is not advised. It's incredibly repurposable and can be used for a lot of different projects. The adjustable screw on its back makes it very convenient for different purposes. After digital read shows on your Arduino pin and then you are ready to go. It is a great sensor choice for quick prototyping.
Use it on a robot for wall detection and wall follower, or as some of the projects listed below as a trigger system. Its round shape with the screwable holders makes it a good choice for a homemade assembled robot, with a hole of its diameter and the holders you can place it aiming at different positions on a robot. Or even place it near your PC to turn on and off your monitor.
Project 1. Summer inspiration-DIY automatic curtain lift
List of hardware: