HackerRemote is a Bluetooth 4.0 (BLE) remote app for your electronic projects, such as robots and copters. It can be used with arduino and a BLE to serial module, such as RedBearLab BLE Mini and DFRobot Bluno.
This app has several virtual keys and a virtual screen. When the keys are pressed or released, the key state are autonomically sent to BLE devices. And the app can also receive strings from BLE devices and display them on the screen.