Hi,
I'm new to Arduino, and have a great idea for a project. Part of this project is to detect if you're indoor or outdoor in general (so not that I install some sensor in my house only to detect this). Would there be some general approach to tell the difference between indoor and outdoor, and if so, how would you do it?
Thanks!
Jan Willem Tulp
If you're in Scotland, you could detect if it is raining or not.
good call @awol 
I would say there is no specific factor like light conditions, humidity, temperature, ... , which could tell you precisely wheather you're in- or outdoors.
For what kind of project do you need this capability?
Maybe something like an ir-diode on the ceiling and an ir-receiver attached on your project could do the trick?
An GPS-Shield would mabye work too, but the accuracy indoors is mostly bad.
@Jan Willem
How do you detect if you are indoors or outdoors? what is your internal algorithm?
How big may the detector be?
I would check for UV light which is almost non existant inhouse.
Furthermore you couldl have a light detector that does an FFT on the light signal to detect a serious 50Hz (or 60Hz) component.
An GPS-Shield would mabye work too, but the accuracy indoors is mostly bad.
Actually, that might give you the answer - if the GPS can't see any satellites, assume you're indoors 