Each Model of HC Bluetooth is very popular for using with any Microcontroller such as Arduino or STM. Bluetooth is easy for you to control wirelessly any device in short rang via your Phone or Computer. Bluetooth model of HC have communication protocol UART.
The CNC Shield v4 is made for the control of 3D printers, milling and engraving machines. This version of the shield has 1 motor driver less than its predecessor, but is more compact and has room for an Arduino Nano. This board has 3 sockets for the installation of stepper motor drivers such as the A4988. Only 2 channels per motor are required to control this motor. There is also a connection for 2 end-stop switches per motor.
The Arduino Mega 2560 is a microcontroller board based on the ATmega2560. It has 54 digital input/output pins (of which 15 can be used as PWM outputs), 16 analog inputs, 4 UARTs (hardware serial ports), a 16 MHz crystal oscillator, a USB connection, a power jack, an ICSP header, and a reset button. It contains everything needed to support the microcontroller; simply connect it to a computer with a USB cable or power it with a AC-to-DC adapter or battery to get started. The Mega 2560 board is compatible with most shields designed for the Uno and the former boards Duemilanove or Diecimila.
The OLED displays are one of the most attractive displays available for a microcontroller. It has a good view angle and pixel density which makes it reliable for displaying small level graphics. Interfacing this IC with MCU can either be done using IIC or using SPI hence helps to save some pins as well.
So if you are looking for a slim, attractive and efficient display module to make your project look cool with graphics then this module might be the right choice for you.