LCD display

LCD can be added or removed to configure the radio. The idea is that you don't need the LCD while flying, so while bother with it on the radio ? LCD is just needed to tune the configuration. A connector on the radio allows to plugin the LCD when needed. The LCD panel also has 4 buttons which are used to navigate throught the menu and set the various parameter.  

LCD is soldered on a protoboard and a 16 pin connector is added. The 16 pins connectors inserted into the female glued inside the transmitter.
The control of the LCD is done by the Arduino with only 7 pins: 4 bits for data and 3 bits for control. The switches also use 4 pins on the Arduino.
The other 5 pins on the right are used for the 4 buttons for navigation. One RC a 6+5 pins connector is glued near the surface to easily connect the LCD.