I currently have my Raspberry Pi 3 configured so that it provides a wireless access point. I mostly followed this tutorial, although I changed a few things. I would like to be able to see every device that has been on my access point. Is there a way to do this? If possible I want to be able to see the date on which the devices first came onto my wifi also. I want this so that I can have a count of how many different devices have been on my wifi.
The following command will show you devices currently connected to your hotspot:
arp-scan --interface=wlan0 --localnet
If your hotspot is not on wlan0 adjust the interface option appropriately
Of course you'll have to do more work on formatting the output of it. It was the above command that helped me in the project based on the same tutorial that you followed.