Custom bluetooth device

I am looking for someone to draw up a blue print for a customized bluetooth device. I am wanting a small bluetooth button that will open an app on a phone. Eventually I will be wanting the mobile app made but I am looking for the button to be not noticeable like in a necklace or a ring. I would want it protected so it doesn't go off by itself but is easy to get to in a quick manner. I am needing the blueprints of a working device for funding for my project. I am not sure if this can be done without the app itself but I am hoping that as long as I can sync that bluetooth device with a particular app then it should be fine. I do not need it to do anything else besides open or alert the app. The app should be able to do the rest. I am not sure how much a normal blueprint would be so I am open to bids that do not fit in my bidding range. I do not have funding as of yet so I am paying for this out of pocket until I can get the funds. I am open to suggestions about my project to make it happen.