Dave Bryan, who is a security penetration tester (and president of the Hack Factory), bought a Raspberry Pi a few weeks back and decided to use it to wardrive around Minneapolis. He took a RasPi Model B and added a 32-gig SD card, a ReaTek wifi adapter, a mag mount wifi antenna, a GPS receiver, and a 12,000 mAh USB battery pack.
From that I did a little bit of driving and biking with this tool kit, passively looking for and logging networks. I could have easily used my NinjaTel phone (and will attempt this in the future), but I wanted something that I didn’t have to mess with to much and would have a long battery life to “power all the things”.
From this I found that out of 6,164 APs identified, that only %5 had WEP configured (which is flawed). That is a total of 327 APs that still had WEP enabled. Not to bad as a basic health check. Of course more data would always be better.