Hi! I helped build Shortwave. There are some interesting limitations to the ibeacon and corebluetooth APIs that we used - corebluetooth can broadcast in the background (but not receive) while ibeacon can receive in the background (but not broadcast).

Our goal was to be able to recognize that two shortwave users were within range of each other, even if both phones were locked, so we had to find a way to make these two APIs work together.

I'm working on a blog post that details how we did this. I hadn't thought of open-sourcing the code, but people seem interested so I'm more than happy to do so. I do have to warn you - this was my first foray into objective-c, so I'm sure there will be some shortcomings :)

I'll post it to hackernews when I wrap it up. I'm also @alonsoholmes on twitter, in case it doesn't make the front page.

Cheers!

- ah

Hi, We are working in a project that also uses Bluetooth Low Energy for nearby interaction (though is not a chat). So we do some similar stuff to have Beacons advertising in the background. Due to the demand we saw here, we decided to open source our library which is called AltBeacon. You can find it in https://github.com/CharruaLabs/AltBeacon , we need contributors so feel free to check it and contribute.

It's actually very simple. We've released a much more featured version of this at http://getloopd.com