(1) 3D Printer Controller RAMPS 1.4
The RepRap Arduino-compatible MEGA Pololu Shield, or RAMPS for short. It is designed to fit the entire electronics needed for a RepRap in one small package for low cost. RAMPS interfaces an Arduino-compatible Mega with the powerful Arduino-compatible MEGA platform and has plenty room for expansion. The modular design includes plug in stepper drivers and extruder control electronics on an Arduino-compatible MEGA shield for easy service, part replacement, upgrade-ability and expansion. Additionally, a number of Arduino expansion boards can be added to the system as long as the main RAMPS board is kept to the top of the stack.
Version 1.4 uses surface mount capacitors and resistors to further cover edge issue cases.
(2) Arduino-Compatible Mega 2560 R3
Fully compatible with original Arduino  MEGA 2560 R3, with this product , you are able to use all the Arduino open source platform to create or learn interactive objects , it will be a lot of fun while you are creating and learning it , so just get this and start it , we also provide reference pdf files that can help you to improve skills very quickly . after all , time matters , the sooner you can improve your programing skills , the sooner you can create amazing projects !
Compared with UNO R3 , this is with main Chip ATmega2560 , with more I/O Pins , and additional  10 PWM output , of course , the EEPROM is also with larger space.
(3) A4988 StepStick Stepper Motor Driver Module
A4988 is a complete microstepping motor driver with built-in translator for easy operation. This product is available in full, half, 1/4, 1/8 and 1/16 step modes operate bipolar stepper motors, output drive capacity of up to 35 V and ± 2 A. A4988 includes a fixed off-time current regulator, the regulator in slow or mixed decay modes. A4988 converter is the key to the easy implementation. As long as the "step" input inputting one pulse drives the motor one microstep. There are no phase sequence tables, high frequency control lines, or complex interfaces to program. A4988 interface is very suitable for complex microprocessor is unavailable or is overburdened.
In the micro-step operation, A4988 chopping control inside automatically selects the current decay mode (Slow or Mixed). In mixed decay mode, the device is initially set to a fixed downtime in some fast decay, then the rest of the slow decay downtime. Mixed decay current control scheme results in reduced audible motor noise, increased step accuracy, and reduced power consumption. Internal synchronous rectification control circuitry is provided to improve the pulse-width modulation (PWM) operation power consumption. Internal circuit protection includes: thermal shutdown with hysteresis, undervoltage lockout (UVLO), and crossover-current protection. Special power sequencing.
