Nice DX8 and hexcopter in the background there too. I've thought about doing something with Arduino and GPS to make a surveillance bot of some sort for fun. More of a Futaba guy myself, but I do use DSM2 for some of the BNF stuff (TX powered by Eneloops, of course), but I digress...
Oh, if anyone was interested, there is a TI-89 emulator for Android too on the Play Store (both free and pay versions). Doesn't come with the ROM though, but those aren't too difficult to come by. I think you can actually just download them from the TI site, perhaps only technically legally if you own the actual calculator, but I'm not sure.