qwerty_asdf

Hello! I want as a hobby to work on this project: I want to find a board that when a button on it is pressed the signal H will be send in my mobile device. So I have some questions: 1) How are they going to be synced? As I think, the easier would be via Bluetooth. So the board I will use must have it. I have searched the web and I found arduino for that job, which is also easy to program it. But I search for something smaller and cheapier because I want to buld something specific as far as the cost in concerned and the size. So what do you suggest? I am thinkinh that I can be implement my own circuit wth the button but what must I use then for the bluetooth? Ideas?