Add RF interface of nRF24L01 Add Nokia 5110 LCD interface, which is very convenient for game development. Add a Bluetooth module interface to facilitate Bluetooth wireless serial communication. I2C communication interface is added to facilitate the connection of I2C devices. At the same time, JoyStick Shield has 1 PS2 cross-shaped rocker with buttons, 4 round buttons and 2 small buttons. Provides Arduino joystick and key input expansion. The on-board switch can be switched between 3.3V and 5V, and this module can be used for other 3.3V microcontroller platforms, such as STM32.