This app uses ARKit on iOS to display WiFi strength by adding a colored sphere to the scene. Please note that the app using a private API to access WiFi signal strength, so it will not be approved on AppStore.
This idea is from a video made by a google engineer Ken Kawamoto.
AR Sensor is the Android app made by him on Google Play
Thanks @CTKnight for provide origin information.
Push the green download button, then just run it in Xcode