This is a good tool to detect the intruders on your WiFi.
Disclaimer: it seems that the publisher's website is closed. The software may no longer work on your computer, or run with recurring error message.
Wi-fi connection is now available everywhere so that programs meant to crack them became widely used. For you to avoid your Wi-Fi network being hacked there are two solutions: set complicated password to your network or use Who Is On My WiFi.
Who Is On My WiFi helps you identifying who is hacking your network. For that, you have to set a list of authorized users which is used as a reference. Once done, launch the application and it will do the rest.
Who Is On My WiFi is working permanently. As long as you log on your computer, it will automatically run. And once an intruder invades your network, the software sends you a notification with the unknown device on your network.
This is a trial version. It seems that the full version is no longer available for purchase.