I need advice on creating a simple device, a proximity sensor that will beep/signal when triggered/breached ?. Just like a car, but the thing will be static (like on a wall). Trying to create something to help my blind doggie to get her bearings in the house (like the bathroom door, etc). I’m a software guy (C#, etc) so I can code, but never done a project like this. Any suggestions would be appreciated. Thanks in advanced.