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Release status: Working

Description RAMPS eXpansion Board
License GPL
Author SZiv
Based-on RAMPS
Categories Electronics
CAD Models https://github.com/SZiv/RAMPSXB
External Link none



RAMPSXB (RAMPS eXpansion Board) is a shield that attaches to the AUX pins of the common 3D printer control board, RAMPS.

It adds 4 additional stepper motor driver carriers, 4 additional thermistors, 4 additional PWM-controlled MOSFETs, EXP1 and EXP2 for an LCD controller (such as the RepRapDiscount Smart Controller), additional VCC pins, 5V pins, regulated TX/RX for an HC-05 chip, and suppression capacitors on the minimum endstops, similar to the RAMPS 1.4.2.

This allows for a variety of combinations, including 6 completely separate extruders, or a mixing extruder and a few fans, or a mixture of voltages (12V on the main RAMPS, and 24V on the RAMPSXB). It was originally designed to run either the E3D Kraken or Diamond Hotend, with some spare heaters for fans, lights or support extruders.

RAMPSXB consumes the maximum endstops, as well as servo pins 2, 3, and 4 to drive the FETs.

Reverse Polarity Warning

Generation3Electronics-achtung.gif Do NOT reverse polarity on the input pins, as there is no protection diode. Reversing polarity will not only fry your steppers and FETs, but may even damage your Arduino and possibly even your computer. Triple check to make sure the polarity on your power input is correct!


RAMPSXB Board Layout, as of V2.2


RAMPSXB Schematic as of V2.2

Open Source Files

EAGLE files can be found here: https://github.com/SZiv/RAMPSXB

Where to get it?

No manufacturers for this yet. ¯\_(ツ)_/¯ Nothing is too hard to solder, so if you can get ahold of the board, its not very hard to assemble.

RAMPSXB-TH (RAMPSXB-Through Hole), a fork

Must also comment on choice of Protected_Mosfets available when making Sinaptec, RAMPS and RAMPSXB. Basically this is a 2.5 layer or 3 layer board, i want it all to be through hole, as I am sick of buying new (hard to source) SMD components. This will be a fork. Spacewise how would the board look, is adequate spacing available for through hole components? 1/4W resistor, 3mm LED, through hole MOSFETs...
MOSFETs: yes, fork?
3mm LEDs: yes
capacitors: TBD, how can you standardize to 0805
resistors: yes

Response from SZiv:

There is not currently enough space to make everything through hole. The RAMPS side of the board can't really be touched without running into something on the RAMPS, but the other side can be knocked out and make the board longer. It will be more expensive a board to make, but the parts will be easier to source. I'll try and make an offical though hole version in the next few days because it sounds like an interesting challenge, or if you want you can fork the official repo and try it yourself. Any comments on the MOSFETs or do you think a through hole STP55NF06L would work?

Response from Jobo:

Protected_Mosfet: any type of N channel MOSFET will work depending on your Voltage and Current capacity/requirements.

100 uF capacitor, 4 pieces under motor driver chips, use same size as in SinapTec, had the same problem in SinapTec so make sure the size is correct.

Will through hole capacitors (8 X 14MM) fit into the circuit, is it necessary/possible to move the 4 10k resistors down in the design

Response from SZiv:

The capacitors that go under the drivers are filter capacitors that just connect VCC and Ground. Best I can figure out is that they are used to smooth out voltage spikes.

I ripped up all the traces and bumped the board out quite a bit to make everything fit, replaced all the resistors with 7mm 1/4W resistor slots and varying capacitor sizes I just pulled off of the capacitors of the same size I have lying around here, and heres what I've got:

Prototype RAMPSXB-TH Schematic


I'm not sure when I'll get a chance to run the traces, and I am waiting on verification that the circuit does indeed work before I tackle that. Once I get around to getting it done, I'll throw it up on github, or if anyone else gets a chance to finish it off, put it up and I'll throw it on the official github.

Any other ideas?

Response from Jobo

Not yet, many thanks for your work

Pin Definitions

E2 Direction - 15
E2 Step - 19
E2 Enable - 63
E3 Direction - 2
E3 Step - 39
E3 Enable - 58
E4 Direction - 42
E4 Step - 44
E4 Enable - 43
E5 Direction - 32
E5 Step - 47
E5 Enable - 57
Thermistor T3 - A11
Thermistor T4 - A12
Thermistor T5 - A10
Thermistor T6 - A5
MOSFET H6 - 45

Bill of Materials

Location Description Quantity Package Notes
C1,C2,C3,C4 Electrolytic Capacitors, 100uF, SMD 4 0605 For Stepper Carriers
C5,C6,C7,C8 Electrolytic Capacitors, 10uF, SMD 4 0405 For Thermistors
C9,C10,C11 Nonpolarized Capacitor, 0.47uF, SMD 3 0805 Suppression Caps for Endstops
R5,R6,R7,R8,R19,R20,R21,R22 Resistors, SMD, 100k Ohm 8 0805 For FETS and Pulldowns
R1,R2,R3,R4 Resistors, SMD, 10k Ohm 4 0805 Pullup Resistors
R15,R16,R17,R18 Resistors, SMD, 10 Ohm 4 0805 For FETs
R11,R12,R13,R14,R27 Resistors, SMD, 1.8k Ohm 5 0805 LED current limiting resistors
R23,R24,R25,R26 Resistors, SMD, 4.7k Ohm 4 0805 For Thermistors
R10 Resistor, SMD, 3.3k Ohm 1 0805 Half of a Voltage divider for the HC-05 Chip. No HC-05? You don't need this!
R9 Resistor, SMD, 2.2k Ohm 1 0805 Other Half of a Voltage divider for the HC-05 Chip. No HC-05? You don't need this!
Q1,Q2,Q3,Q4 MOSFET, PSMN7R0-30YLC, SMD 4 TO-220 Main Power MOSFETs. If using V2.1, use 3 stp55nf06l instead.
N/A TO-220 Heatsinks 4 TO-220 Heatsinks for the FETs. Not required, but dirt cheap and suggested if using through hole FETs.
LED1,LED2,LED3,LED4,LED5 LEDs, SMD 5 0805 LEDs that tell you if the FETs are on, and one that tells you if main power is on.
N/A Screw Terminals 5 3.5mm Input/output power terminals. If you need more than 4A, solder directly to the bottom traces.
F1 PTC Fuses 1 N/A 30V, 9A if you cover the bottom traces with solder for extra power, 6A if you don't.
N/A Male/Female Pin Headers A lot? ¯\_(ツ)_/¯ 0.1" spacing. Buy a couple of Female double rows, male double rows, male single rows, and female single rows.
N/A PCB 1 N/A The Actual PCB. I get mine from OSHPark, but you can get it from SEEED for better prices.