Cool Additions to the iPhone
I've said it before, but I'm going to say it again: I think the iPhone would be a lot cooler if it had a temperature sensor on it. In terms of technology, all it is a single temperature controlled resistor (called a thermistor), probably worth about 5 cents. But it would be cool to be on a patio and be able to see how hot it is.
I also think that if everyone opted in to given this data to a central repository, that it would be possible to increase the accuracy of our existing weather models a great deal. Currently weather models are primed using sparse initial conditions. For example, in Vancouver, I believe the only data comes from downtown, the north shore, and a weather station out in Richmond. So, three points representing a whole city.
Another good idea came from my friend Alex - having a pressure sensor in the iPhone would also allow it to report altitude fairly easily. That would also be another great point for weather data, and another interesting piece to submit to a public repository.
Anyways, just a few random ideas. But given that the iPhone already has a compass, both a temperature and a pressure sensor don't really seem like crazy ideas to me anymore.