@Edent I love solutions like this. One way to get network wifi I found was to use an old phone (in my case one running Ubuntu Touch, but this works on any platform) sharing the mobile over wifi via "hotspot". Even without the mobile connection, all devices are on the wifi, and can see eachother for reliable connectivity. Don't even need a SIM in the wifi access point phone. Worked well for us playing silly games in a pub.