Sundials and improvised compasses

I joined iPhone Nation a month or so ago. The iPod touch was my gateway drug. It seemed harmless enough at the time, but things got out of control. Now I’m one of those people. One of those iPhone people. You know the kind. Even I think we’re insufferable.

Anyway, I’ve been having fun with the applications available at the App Store, and one that caught my eye was Masayuki Akamatsu’s Compass. Here’s a little video on how it works.

In a nutshell, here’s the theory. If you know where you are, and you know which way is north, and you know what day of the year it is, you can build a sundial that keeps very accurate time. (If you don’t know what day of the year it is, you can build a sundial that’s reasonably accurate, but that’s another matter.) Stated another way, if you know what day it is, and you know where you are, and you know what time it is, then you can build a sundial that will tell you which way north is. It turns out an iPhone has all the information it needs to build just such a north-pointing sundial. Which is to say: a compass. No magnet required.

I had a similar thought four years ago when I was noodling around with some sundial code in MATLAB. I even wrote a contribution for the MATLAB Central File Exchange called Building Sundials. That contribution came with some explanatory text that closed with this statement.

Suppose you were lost in the woods, equipped with only a computer, a printer, and a copy of MATLAB. How would you orient yourself?

I meant it as a joke, but that’s essentially where the iPhone has gotten us.

Okay, I admit that a real compass is cheaper than an iPhone. And it works at night. Without batteries. And when it’s cloudy. But still… Hey, did I show you my beautiful new iPhone?

Pandora Radio on the iPod touch

A few weeks ago I wrote about how my iPod touch serves the purpose of a laptop in the kitchen. With the advent of the new iPhone 2.0, I was able to upgrade my iPod software (for $10) and get some of the new iPhone Apps. Among the apps are two that I suspect I’ll use a lot: Pandora and

I’ve been hearing good things about the Sonos system, but that seemed like overkill for my needs. I just want to listen to nice music when I’m in the kitchen. Sonos lets you pick any music you have on your computer and listen to it anywhere in the house. But here’s the problem: I can’t be bothered to pick out music, even the music that I own. I get lazy and listen to the same few things over and over. I actually prefer the way Pandora and present my musical options. Just pick an artist or a genre and press “go”. That’s about my speed.

This is what convergence looks like for me. I’m happy getting my music streamed to me through my wifi-enabled iPod using these two services. The iPod sits in a little speaker mount next to a big Bose radio/CD player that I never use anymore.

How does my iPod know where I am?

For years my wife has wanted to be able to check email from the kitchen downstairs. Seven years ago she convinced me to buy a laptop for this purpose, but it didn’t get used much, partly because of some trouble with the mail client she was using at the time… checking for mail from two different locations is a pain from a non-web client. Since then she converted over to Gmail, which solved that problem. So she wanted to try again with the old computer. We even went to the trouble of refurbishing the old crappy seven year old laptop (she insisted), and oy! what a dog it was! It worked, but everything took so long.

The solution to the problem turned out to be an iPod touch. I suppose I shouldn’t be surprised, but it’s amazing how much better a computer it is than that old laptop. It’s small and handy and also doubles as the source of music in the kitchen.

The iPod touch is essentially a really thin iPhone without the talky part (or the camera, sadly). It can’t make calls, but it can talk to a WiFi network. I knew it had the basic features I wanted, but I was nervous about the virtual keyboard being too much of a nuisance. I am happy to report that it makes an excellent kitchen computer, especially in a kitchen as small as ours. The instant-on startup time is a wonderful thing, compared to even a modern laptop, and the wireless connectivity is terrific. My son Jay is autistic, so I spend a lot of time walking around near him to make sure he’s not getting into trouble. The touch has just the right form factor for carrying unobtrusively while I check email and Twitter, and then slipping into my pocket when Jay needs my attention.

It took me a long time to get with the mobile revolution, but I’m happy with this as an entrĂ©e.

One thing I’m still puzzled about. The mapping application, Google Maps, works really well, and if you push the little “tell me where I am” button, it accurately positions you on the map. I knew this feature existed, but I thought it worked because of cell phone tower location technology. But this iPod is not a cell phone. I would have guessed that all it knows is my IP address, and I didn’t think IP addresses could be pinned down to within a hundred yard radius. So… how does my iPod know where I am?