Can a Raspberry Pi Zero W be turned into a WiFi router and using USB cable to debian computer as it's internet connection

Question

The question tells almost all. I have a Pi Zero W at my balcony. It's connected to my home router through wifi. For now it's running lighttp server, taking a picture every minute and measuring temperature and making a nice plot of last weeks temp measurements and showing them when asked.

Problem is that my home router gives a terrible wifi signal outside house (in balcony it works but 10 meters from there it dissappears) and I was thinking to turn that Pi Zero W to a wifi router because it is already out there and so I would be able to use my own internet connection when sitting in the park out there. I can always buy a usb-ethernet adapter and a long cable (10 m or more) and make it happen (I hope). But I have much nearer a small debian server running inside house just on the other side of the wall and would need only 2 m usb cable if I connect that Pi Zero W directly to it. That debian server does not have free ethernet ports but it has free usb ports.

As far as I understand it should be possible but I have had no luck in finding instructions how to do it. So any hints and links would be highly valued.

Answer 1

You can use USB Gadget Mode to use the OTG USB port on the Zero as a network port by adding dtoverlay=dwc2 to /boot/config.txt, and adding modules-load=dwc2,g_ether to the end of /boot/cmdline.txt. This will cause the Zero to emulate a USB network adapter if you connect to the Zero using the OTG USB port. Depending on the specifics of your debian server, this will work as a normal, albeit slow, network connection. By default, it's going to use lan-local (169.254.0.0/16) addresses, so you'll need to do some work to configure your debian machine indoors as a router.

The downside is that performance of both the on-board wifi and USB gadget-mode networking isn't the greatest. So yes, it certainly can be done, but the results may not be worthwhile.

Answer 2

If USB Gadget is enabled a virtual ethernet channel can be created over the USB interface. Adafruit have made a nice article about "USB gadget" that explains all steps in detail: https://learn.adafruit.com/turning-your-raspberry-pi-zero-into-a-usb-gadget/ethernet-gadget

There is restrictions like the onboard antenna in form of coverage/range. I would guesstimate that the restriction would be in the air interface due to distance between AP (RPi Z W) and your laptop.

The steps to configure this is not so extensive and worth exploring and following the URL provided should get you going in a jiffy.