Arduino Outdoor Sensor system

I have a robot and I would like to be able to have it detect indoors from outdoors. What sensor(s) can I use to accomplish this. I have thought about sonar pointing towards ceiling but the rooms might be large >25 feet.

Thank you for your help

You use photocell sensors to look for sunlight or darkness under cover.

Hm... interesting question.

The ceiling test could give a "false indoors" if the robot went under a tree or something, and the light / dark test won't work since both indoors and outdoors can be light or dark from time to time.

Tricky AI problem this: we as humans "know" what it means to be indoors or out, but to define that (which is what you have to do before you can test for it) is amazingly tricky. One of those things that separate us from machines?

You would have to calibrate it to know when it's outside. There is a tremendous difference in light when your outside then, when your inside a building. Being human and using our eyesight to realize we're outside is how we would interpret this.

There was a video of a guy who made automatic sunglasses. When you would outside, the sunglasses would flip down. In the video, he would be standing right inside a house with the door open and soon as he stepped out, the glasses would flip down. Walk in one step, and they would flip up. Granted, he didn't walk around outside under shade, but in the video, he wasn't ever in direct sunlight. So, I really think the idea of using photosensors would work with the right algorithm.

I will search for the vid and if I find it, I will post it here.

Is there any UV sensors I can use? I would not know were to get one or how to make one. I do have a UV led though

Did someone say detect outside during the day?

What if you are outside at night? How would you detect that??


What if you are outside at night? How would you detect that??

I would like to know how to do that as well.

Detect bat calls?