RepRap Arduino Mega Pololu Shield (RAMPS) based electronics have been one of the most common RepRap control boards for quite some time. The most widely used version is RAMPS 1.4, which was developed in 2011.
For more details about RAMPS, please see the RepRap Wiki pages - specifically, the overview page and the page on RAMPS 1.4. This page does not intend to duplicate any of the information on those pages.
While RAMPS 1.4 is an excellent and capable control board, it has a few oft-encountered limitations. To attempt to address this, we have developed an updated version on RAMPS (dubbed RAMPS 1.4.3).
Works with 24V
RAMPS 1.4 and earlier made use of re-settable polyfuses which were limited to a maximum of 16V. However, it is not uncommon to run a printer at 24V - in which case the fuses needed to be removed and a substitute devised.
RAMPS 1.4.3 makes use of mini-blade automotive fuses, which are available in a range of voltage and current ratings - easily sufficient to run at up to 24V. These fuses are not re-settable, but can be easily and cheaply replaced.
Capacitors C3, C4, C6, C7, C9 and C10 need to be 24V tolerant - preferably with a significant safety overhead. On many RAMPS 1.4 boards, these capacitors are only rated to 16V - though the original design does call for 35V. RAMPS 1.4.3 boards are assembled using 35V capacitors.
TO220 STP55NF06L MOSFETs have been replaced with SMD IPD036N04L G MOSFETs. The new MOSFETs have much a much improved RDSon rating, which means less power will be wasted as heat during operation. In addition, the new MOSFETs allow for higher current draw, although the PCB or attached fuses will likely be a limiting factor long before the MOSFET.
Two extra low-power MOSFETs have been added to drive smaller devices (fans, LED lights). This makes it possible to still control two fans while running a dual-extruder printer. Basically, we built a TinyFan board into RAMPS 1.4.3.
Selectable Logic-Level Voltage
A jumper has been added to the board to allow selecting between 5V and IOREF voltage levels throughout the board. This allows using RAMPS 1.4.3 with a 3.3V Arduino - such as an Arduino Due. However, there is no official support for using RAMPS in this capacity - this is really just for people that want to experiment.