Smartphone as a touchpad and keyboard (for the moment it only works as a touchpad) using an additional bluetooth device, which implements the USB-HID specification.
It is necessary to build the additional device, it can be created with a microcontroller and a bluetooth module, the application sends a data string (touch + "," + left + "," + right + "," + Dx + "," + Dy + "," + "c" + "," + "0" + "\ n") that can be interpreted with a microcontroller and a bluetooth module that together behaves like HID.
Some of the things that could be done with the app:
1. Simulate a graphic tablet.
2. Work like a mouse.
3. Function as a keyboard. (function to implement).
Note: My application is not yet in optimal condition so there may be problems when using it.