Can you stop certain devices from using your wifi? For example if I only wanted my computer and phone to have wifi but not my ps4 would that be possible? And if so how could I add it back?
superhulk: Most routers support white lists or black lists. With a white list, only devices whose MAC addresses are configured into the router can use the connection. With a black list, devices whose MAC addresses are configured into the router are blocked from using the connection.
Of course, if you are the only person using the devices concerned, simply delete the WiFi profile (connection details) from the device that you do not want to use WiFi. If a device is not configured to use a particular WiFi it won't use it. Make sure that your WiFi is encrypted – WPA2 is the most secure encryption. You should also disable WPS in the router if it has this feature. A device cannot connect to an encrypted network if it does not have have the network's pass phrase.
Unfortunately, in Windows 10 (which does not apply to the PS4), Microsoft made the insane decision to include a facility whereby a Win 10 computer could automatically connect to an unencrypted WiFi network without any user intervention. I believe there is an option to disable this feature if you can ever find it. I have added this note in case others are reading this answer.
I hope this helps.
Just disconnect the device you don't want using the wifi at that time, then add it back when you want it back on
Change the WPA2 password on it and restart the router.
Give out new password to the device you only want to connect to Wifi
In your Router/s Settings there is an option to Block the MAC Address of the device you want to block.