Any fancy tool to declare and log new loggers to a network ?

Why not block all access to the network except for your devices, it's a standard feature of most routers, if the device's MAC address is not listed in the allowable "Whitelist" they cannot log into the router. this is useful as every device has a MAC address that is totally unique on the planet. the other option in addition is to use a 30+ character random passphrase and change it daily or weekly - they usually get bored of stealing bandwidth quickly and pick on someone else

Other options are not to broadcast your SSID and change it regularly too

I stopped bothering to hide my SSID when I read this
Debunking Myths Is Hiding Your Wireless SSID Really More Secure - HTG

the other half have those weird android apps that can find out WIFI passwords in a weird undeclared way

I don't know what this refers to. I just rely on using a very strong WiFi 'Security key' [password].

Why not block all access to the network except for your devices

And I agree with Barman58 that this is a very effective measure that is even better than a very strong Security key.

Denis

This one is free but maybe you won't want it running if it never detects anything:

Bitdefender Smart Home Scanner - Free IoT Vulnerability Scanner

Online DNS hijacking check:

F-Secure Router Checker — Is your Internet connection safe? | F-Secure

@Barman58 @Try3 @Callender
Let me share with you how hacking Wifi has advanced and how idiots around me are just doing routines they can find on the internet to do it with minimal knowledge of what they are doing yet is very effective .

- Basically they use a popular Linux Distro called BlueTrack (BackTrack with few more hacking tools added)

- The Wifi scan on such distro can detect hidden SSIDs

- They use something called the Evil Twin hack , they add 2 wireless adapters to their PC where one tries to clone MAC address and SSID of the victim router with a higher through-put gain so trap any of your Wifi devices to connect to it rather thinking this is an Access Point then your device tries to authenticate handing them the Wifi password then the second wireless adapter broadcasts back to your Wifi router all your device requests so that it is actually playing as an undetected middle man that steals your password with ease

- They can also change MAC address to any found on the network , White Listing does not help much

- But can a clones MAC addresses co exist on same network without colliding ? Theoretically no but in reality what happens is that last one to connect gains access to the network while the older one is revoked , so they pick a MAC address of a device not in use or has low traffic to clone , the device will still show connected to Wifi but yet won't be having internet which you might not come to notice until late and all you can do is restart your phone or reconnect your Wifi etc.

- Also there are enormous numbers of Apps on Google Play Store that can give you passwords for SSIDs you try to connect to by downloading them from an online database , how is that database maintained or how they manage to recover all those sort of passwords is unknown , probably a popular app steals them from victim phones or they exploited some Google service , who cares

So like you see non of the trivial advises work on these approaches , I am surrounded by idiots who had been taught by pros

The only mean I can see fit to overcome all these blahs is to constantly monitor for the number of devices on the network , as even devices with cloned MAC addresses count as an extra one , so if anybody knows a tool that can do so please share .

You could use the command line options of NirSoft's Wireless Network Watcher to count /identify the connected devices.

Perhaps the most covenient way would be to put it in a batch files that also processes the result so you get a warning if the count / device list is incorrect.

Denis

1 NirSoft's Wireless Network Watcher has its own methods of logging its results and they are described on its download page.
2 But you would then need to be able to write a script that reads the log, extracts device names and reports back to you. That's the only alternative to stopping what you are doing and reading the results yourself.
3 The whole job would be controlled by a Task scheduler Task which you set up to run frequently.

If you don't have the necessary skills then you will be better off with one of the solutions Callender suggested.

Denis