Sharing cellular Internet without a hotspot or Bluetooth

For the past couple of years, Team 3489 has created a mobile app for capturing scouting information. Last year, we used Internet-over-Bluetooth to get internet connectivity to our six tablets so that they could push data to Firebase. Unfortunately, the Bluetooth connections kept silently dropping, which is a problem when you’re trying to capture information in real-time!

We’re trying to set up a Raspberry Pi and Ethernet solution this year, but have run into issues with not quite enough networking knowledge to pull it off. For a deeper explanation of what we’re trying to do, what hardware we have, and what we’ve already tried, check out our post on the Raspberry Pi forums:

If you have suggestions for us, feel free to reply on the Raspberry Pi forum or on this forum… I’ll be checking both places. Thanks in advance for sharing your knowledge with us! Go teams!

If the pi doesn’t work out, one could use a laptop with linux and set it up as a router/DHCP server (use with an external Ethernet switch, obviously). Same thing as what it sounds like you want to do with the Pi, but on x86 (32 or 64) you sometimes get better driver support than on ARM.

At least for me, USB tethered phones show up as USB ethernet devices (on my laptop’s Arch install at least) so once connected and tethered it shouldn’t be any different than a “normal” linux DHCP server/router setup.

As for the linux side, laptop or pi, I’d suggest using DNSmasq. This is what DD-WRT and other router firmwares (optionally) use for DHCP serving. I’ve seen links where people have set up pi’s as DNS servers using such, so using it as DHCP instead should be possible. As for routing, use iptables.

This is for arch, but most of it (other than the installation of packages) should more or less work on any distro: