I just read on the description of a YouTube vid that Parrot AR Drone creates its own wifi hotspot. How does it do that? Is it possible to do a similar thing for a UAV project I've been thinking about?
It has hardware inside that allows it to act just like a wireless router.
If you wanted to add a wifi hot spot to the UAV project you would effectively need to add a wireless router inside your device. If you had a PC connect you could them give it special drives so what it sends over wifi is what your device needs to be controlled.
To keep it simple, this will not be an easy task.
Roving Networks has some great solutions if you have a connection point. Your microcontoller interfaces through serial and it can act as a bluetooth hotspot. They also have modules that connect to wifi and then you can connect through sockets. This is relatively easy to do with C or java, as they have examples. The microcontroller will still just pipe serial data.
Past Experience with Roving Networks
In my senior design project we used a roving networks bluetooth module to get a bluetooth signal from a sensor connected to the OBD-1 Connector on a car. We placed the device underneath the dash and with a dongle from 40 feet (no line of sight as it was under the dash) still had a signal without a problem. This allowed easy debugging.
When you pick bluetooth the class determines the maximum range, you can get a class one radiator and they can actually use what could be licensed as class three. They just paid the licensing fee to go higher, but chose not to. The roving networks module actually used the maximum power of a class one bluetooth device and coupled that with good receiver sensitivity. The range was very well done.
I would buy a DD-WRT compatible router and flash DD-WRT on it, so you can get features like attached storage and hotspot management. Add ethernet to your device with whatever module you can get and connect them with a patch cable. Then on the software side, you could use Zerconf to let your client know what services it can access, e.g. video and control streams. I believe that many of these routers also support adding an RS232 serial port, and maybe you can communicate to the network via that, but I'm not sure, so you wouldn't have to add an ethernet module.
As an alternative to putting an access point onboard, there are some cellphones and PDA's that might have this functionality. They might be smaller and carry their own batteries but might add weight.