You didn't add the brand of your router.
If it's Mikrotik, you could make a Virtual AP, set password and vola.
Alot of AP have WPS, so you dont have to give your password, using this and MAC filtration, you could remove MAC address of person you gave access to your network and thats it.
Or simply change your password, gave them it, use MAC address filtration and even if they know your password they won't be able to connect.

This was the easies way without using external servers/services.

How to create a guest timed Wireless Pass Key
When computing the N-point FFT of some signal, the result is always divided by N. I can understand why this is the case for a summation over the N points, but often the result of the FFT operation is a vector of length N rather than a summation. Why then is the length-N vector that is the output of the FFT scaled by the number of points (N) used to compute the FFT? Thanks.
