GoBLE is a universal Bluetooth virtual controller on iOS. GoBLE allows you to connect and control robots, mobile platforms, drones or anything else such as unmanned aerial vehicle (uav) with your mobile devices via Bluetooth.
This virtual remote controller has an omni-directional analog joystick and six digital buttons packed in the classic game console layout, which is intuitive for everyone to start with. It is also compatible with DFRobot standard communication protocol, can be easily set to data transmission mode, and has a variety of sample codes for programming reference.
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Runs on both iPhone & iPad... and it's free.