One problem with the Honda Odyssey is that when you kill the ignition, power to the “power outlets” goes off as well. Wanting to provide internet access with the car off meant doing a little work, so I’ve built an “Automotive UPS (Uninterruptible Power Supply).” Now, I can’t take much credit for this “invention” — most of the ingenuity is embodied in the one piece of electronics in it, which is an automotive UPS module I purchased from PowerStream. It is intended for more permanent installation with a second car battery, but I wanted something more portable, so I connected everything up to a traditional UPS battery. Susan found the perfect case at Target, and I supplemented with a bunch of parts (such as the cigar lighter sockets), mostly from DigiKey.
What you see in the picture is my home-built UPS, which will be used to power the router. The router connects to the internet via the Verizon/Kyocera ExpressCard sticking out of the side. When in the car, it connects to an external antenna to hopefully get the widest coverage range. The router then provides internet access to other devices, mostly laptops, through wifi and ethernet.
Interestingly, Verizon offers a device with nearly the same capabilities now, the MiFi:
But in a much smaller package!