Capturing network users' status and auto exporting logs

Hi all,

Bit of a weird one, but i'm getting a little desparate on where to look for some answers to this.

What do I need?

I'm actually in the middle of a networking 'art project' thing of sorts, where I'd like to run a private internet server where users can join, access the interent at their leisure and when they leave the network, a log file is saved automatically saying when they connected, their device name (IP, MAC and whatever else information if possible) and when they left the network. This log file would ultimately be printed through a reciept printer as a kind of representation of network activity in real time. So e.g.:

You connect to the network at 10:50 --> Leave network at 11:00 --> Log file is saved with Info --> Print

What do I need now?

Software! I cannot for the life of me find the proper software to do this. I'm utterly gimped on a mac as I'm not at home with my PC for a while just to add to the trouble. I gave wireshark a go, but I don't know how best to filter it, as the packet stream is so thick its hard to decipher what is and isn't useful. I would like to have set up some auto logging on something like NirSoft Network manager, but thats PC only. So if anyone knows how to filter Wireshark for connections, or of any software capable of logging connection status that would be awesome!

Thanks so much!