Monetizing and Open Source

I would love to be able to go part time at my (currently full time) work and spend more time doing Android dev, but to do that I'll need to be making something out of it. Long term, I'm thinking about the monetization of Wake Me At and other Android development that I do.
There seem to be three options:

1. Charge for the app
2. Put ads on the app
3. Ask for donations

The problem is, I'm a bit of an open source advocate. If we assume that everyone in the world is bad, and they are going to do their very best to get something without paying for it, then 1 and 2 are a problem. I can charge for the app, but then someone could just download the source code and get it for free. Likewise, they can download the source code, and remove the ads. Asking for donations is the only evil-proof source, but then the evil people just won't pay.

But I think people are both lazy and not evil. I think, I hope, that if I were to charge 99p for an app, it's not worth their while to go and download the source, compile, etc. Hopefully at least some of them will do it purely to support my work. Likewise, and possibly even more so, with ads (though I hate ads, as a general rule): hacking into the code to remove the ads won't be easy for non-programmers. I wonder if the source of the ad hooks will even be open-sourcable... it might have private information in it (though I would think that's unlikely).
Anyway, this is just me thinking out loud. All thoughts gratefully received.

Project One: Wake Me At

I realized (thanks to zabdiel's comment on my first post) that I hadn't actually posted on what my first Android app was going to be (assuming you don't count my funky live wallpaper: maybe I'll put that up here some day, might be useful to someone).

It's intended for train travellers (but could have other uses). It's intended to be the electronic equivalent of hanging a sign round your neck saying "Please wake me when we get to Nuneaton", but getting your phone to wake you with an audible (or otherwise) alarm, using its GPS or other location services.

There appear to be apps like this for the iPhone, but I'm deliberately not investigating too much: I'm going to do it anyway as an exercise in learning Android developing, and if it's very different to the other available apps it might stand more of a chance of getting noticed.

Code can be found here:
   http://github.com/spookypeanut/Wake-Me-At

Current state of the app is that you can click a button, and it pops up a map with your current location marked with a (rather too large) X. Still very early days!

It begins (a little late)

I felt I should have a blog about my android development, so here it is. When I created it, a few weeks ago, I thought Android development was going to be very quick and straightforward: it probably would be, but my Java is *very* rusty, and I'm rapidly coming to the conclusion that I don't learn new languages / apis / tools as easily as some. I'll get there, but it's gonna take me longer than I had hoped. Anyway, in the meantime, here's a link to the github repository of my first app, in case you want to follow my (slow) progress.

http://github.com/spookypeanut/Wake-Me-At