Solved! Me and some friends are going on a 5 hours coach journey Is there some form of "battery powered switch"

[Klonoalunar]

For example. a small device perhaps i could even use a mifi device
so that we can play lan games on the way to our destination and on
the way back.

 

[WildCard999]

You could probably use a cellphone as a wifi hotspot however that will probably use quite a bit of data.

 

[Klonoalunar]

We dont really need access to the internet but i have a mifi device that i accidentally broke the sim adapter for, perhaps i could use this without a simcard
and connect via that

 

[WildCard999]

Try your wifi device without the sim and see if it works. If not I'd think you should be able to buy another sim adapter?