People are starting to look seriously at the iPhone 4 as a robotics controller. It's got a full IMU and otherwise looks appealing. You can get all the hardware chip and sensor specs from this excellent iFixIt teardown, but here's just one example: the GPS chip.
It's a Broadcom chip and the refresh rate is "up to 2Hz". The user-accessible data is provided by the OS so the refresh rate in practice may vary, but the hardware looks pretty promising.
Comments
You right, engineers are just conforming to Apples development conditions that require code singing and such. If their job is a bit like mine (engineering technician) I often go "out of the box" to get things done. I'll bet Apple Engineers do the same, personal achievement is a great motivator (hence the odd looking patent applications).
I ran across this for interest sake. Combo with an Xbee setup you could shoot data back and fourth!
http://resolvehax.blogspot.com/2010/10/iphone-serial-port.html
Cheers.
no problem causing USB port
The iPhone navigation works just fine moving 70m/h in a car, and it works on an airplane as well...
@Ryan Fraser
Honestly, I think the apple engineers don't really try all that hard to lock it down. I recall a while back when the engineers submitted some diagrams to the patent office, a couple of the icons on the iphone's screen were jailbreak-only apps, which means the engineers were using jailbroken devices.
I also agree with you when you say that iOS is a pleasure to develop for, xCode is by far my favorite dev environment and it is one of my top reasons to use a mac. Nothing comes close, I can code many times faster in xcode than in just a plaintext environment or even a nice, organized environment like the arduino IDE.
My AR drone is waaaaay easier to fly with the iPad than my best 450 heli and a traditional tx. The ballistics are great and using a WIFI repeater I don't get nearly as manny drop-out as the 2.4 ghz tx.
IOS is a pleasure to develop for, even in an open source environment.
Might be kind of cool to have one IMU that you could just pair with what-ever machine you happen to be operating.