Because the device needs to have as long a range as possible, I wanted to play with the BLE121LR, a Bluetooth Low Energy module from BlueGiga which boasts 200m range (though I've never gotten it that far). I'd used it once before, but wanted to try again. For the first prototype, I tried an engraved PCB. Unfortunately, this module has pads on the bottom instead of castellations, so it was essentially impossible to solder it properly on the single sided board. I couldn't ever get it to program. Bummer. So this was a failure. I did get to play with a couple RGB LEDs to pick the one that I liked the most.

After populating:

The back. It's painful doing single sided boards where you have to do airwires.

The other part was finding an enclosure. I wanted something waterproof (to keep rain and dust out), that glows, and would be fairly sturdy. I found these blinkies on Amazon (http://smile.amazon.com/gp/product/B005XOUPS0)