Here’s a post I made on the Google Plus Raspberry PI community back in the 2012. Reading this again I remembered how actually useful has been and I didn’t want to get it lost
It explains how to easily share the internet connection of your Android phone with the Raspberry PI.
“I want to share something i found very interesting and useful in my first tests with the PI.
If you want your PI to access the Internet without ethernet or even outdoor, you can connect it to your android phone (it may/should work with other phones too) with the USB-microUSB cable, and then activate the USB tethering on the phone. This shoud create a new interface usb0, and simply typing ‘sudo dhclient usb0′ on the PI should get the ip from phone and use it as router. It works with both 3G and wifi connection active on the phone.
It can be useful to previously edit /etc/network/interfaces adding the line
“iface usb0 inet dhcp”
in order to make it automatically get the ip when you plug the usb cable and activate the tethering.
Once the PI is connected, you can also connect to it from the smartphone, via ssh or whatever you want, because the phone and the PI are actually connected with ethernet over usb.
To discover the PI’s ip from the phone, you should use apps like Fing for android scanning the network 192.168.42.0/24 which in my tests (with a Samsung Galaxy Note with ICS) was the network used by the phone’s dhcp after connecting it to the PI.
It’s been very useful in my tests because simply editing the interfaces file made me able to control the PI from the smartphone and have it connected to the Internet, without needing a PC to configure anything.
I even managed to run an X server on the phone to display the graphics of applications executed on the PI, even if it was quite slow.
Hope it helps, and sorry for my bad english.”