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Revision as of 20:38, 21 July 2011 by Joem (talk | contribs) (Assembly Instructions (Version 0.7 - 1.3a))
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Release status: working

Release Version 1.3a
CAD Models
External Link


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Sanguinololu is a low-cost all-in-one electronics solution for Reprap and other CNC devices. It features an onboard Sanguino clone using the ATMEGA644P though a ATMEGA1284 is easily dropped in. Its four axes are powered by Pololu pin compatible stepper drivers.

The board features a developer friendly expansion port supporting I2C, SPI, UART, as well as a few ADC pins. All 14 expansion pins can be used as GPIO as well.

The board is designed to be flexible in the user's power source availability, allowing for an ATX power supply to power the board, or the user can chose to install the voltage regulator kit for use with any power supply 7V-30V.

Latest Updates

Latest revision: Version 1.3a - Updated July 21, 2011

Version 1.3a has no software changes - the pin assignments remain the same and your 1.2+ compatible firmware should work here fine. The hardware changes:

  • Removed the Molex HDD connector in favor of using the voltage regulator - some power supplies give a dirty 5V signal when there is no motherboard load, so its better to just use the power supply's ATX+4 connector and the 5V voltage regulator.
  • Added a jumper to enable/disable USB auto-reset. This way if you're printing from an SD card using SDSL you can disconnect your USB and reconnect it without interrupting a print.
  • R7 and R8 are now 100k pull-up resistors that are on the stepper-enable lines. This ensures the stepper motors stay disabled and don't move while uploading new firmware, rebooting, etc. The current limiting resistors for the FTDI are gone.
  • There is an extra Z-motor header for Prusa Mendel.

Latest posts in the Forum


  • Small design - board is 100mm x 50mm (4" x 2") - barely an inch longer than a business card!
  • Sanguino clone, Atmel's ATmega644P - ATmega1284 drop-in compatible!!
  • Up to 4 Pololu (or Pololu compatible) on-board (X,Y,Z,Extruder) (A4983 without voltage regulator)
  • Supports multiple power configurations
-- Logic & Motors supplied by ATX power supply (needs molex harddrive connector, and optional 4pin atx connector for additional 12v/supply voltage)
-- Motors supplied by 5mm screw terminal 7-35V
-- Logic supplied by USB bus
-- Logic supplied by optional on-board voltage regulator (molex harddrive connector cannot be installed at the same time)
Supports multiple communication configurations
-- FT232RL on-board for USB connectivity
-- USB2TTL header is available for FTDI cable, or BlueSMIRF bluetooth module
  • 2 thermistor connectors with circuitry
  • 2 N-MOSFETs for extruder/bed, or whatever
  • Selectable 12v(or supply voltage)/5v endstop voltage
  • Edge connectors enabling right-angle connections
  • Silkscreen for connectors on both sides of the board, facilitating bottom cable connections
  • 13 Extra pins available for expansion and development - 6 analog and 8 digital, with the following capabilities
-- UART1 (RX and TX)
-- I2C (SDA and SCL)
-- PWM pin (1)
-- Analog I/O (5)
  • All through-hole components (except FTDI chip) for easy DIY soldering

Schematic & Board Images



Where to get it?!

You can get the bare pcb or a complete kit at:

(if any other resellers have this available, please add to this section)

You will also need Pololu or Pololu compatible stepper drivers such as StepStick

EAGLE files, parts list

Schematics, board, images:


Assembly Instructions (Version 0.7 - 1.3a)

For older versions see Sanguinololu_0.6

For users soldering a 1.3a board, note that you'll have a couple of changes:

  • You'll have a 2-pin male header and jumper shunt to solder for the AUTO-RST function of the FTDI. This is located right above the ATMEGA chip. TODO: Get pics of 1.3a
  • For 1.3a users, R7 & R8 are 100K resistors and are part of the recommended assembly. For 1.2a users, R7 and R8 should be replaced with wire bridges. I use two clipped leads from a previously soldered part to replace the resistors normally in R7 and R8. TODO: Get pics of 1.2 with R7 & R8 bridges


Gather the tools you will need to perform push through hole soldering, and if you opted for the on-board FTDI kit, some SMT soldering as well. Soldering pencil and/or iron, solder, and most importantly: flux! I can't stress how much easier flux makes soldering the SMT device.

Carefully inspect your board for defects. Look for strange connections between traces. Become familiar with the locations of devices from the back as well as the front.

Gather your components and ensure you have the complete parts list for your selection. This photo shows enough parts for two Sanguinololus - one with ATX connectors and the other with screw terminal and voltage regulator.

Sanguinololu 1.0 Build 0. parts.JPG

Soldering the FTDI

Install the FT232RL FTDI IC. Note the orientation of the silkscreen. Solder using your favorite SMT soldering method. The board pictured was tinned from the fabrication shop. After applying flux to the pads, and carefully placing the chip, it was easily soldered by touching the tip of the soldering pencil to the end of pad to tack the chip down, and then on the pin it self to flow the solder correctly. If you're not sure you want to tackle the SMT soldering, you can get the PCB with the USB pre-soldered [here].


 IC100    FT232RL          FT232RLSSOP              

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Sanguinololu 1.0 Build 1. flux the pads.JPG

Sanguinololu 1.0 Build 2. soldered ftdi.JPG

Sanguinololu 1.0 Build 2a. soldered ftdi.JPG

Next install the FTDI components. mind the polarization on the electrolytic (C16).


 J1       USB              USBPTH                   
 C7       0.1uF            CAPPTH2
 C8       0.1uF            CAPPTH2                  
 C11      0.1uF            CAPPTH2                  
 C15      0.1uF            CAPPTH2                  
 C16      4.7uF            CAP_POLPTH2              

Sanguinololu 1.0 Build 3. ftdi components.JPG

Now is a good time to test the FTDI chip. Plug a USB cable into the port. The device should show up as a COM port or a TTY device and allow it to be opened. If you temporarily connect the 'TX' and 'RX' pins on the USB2TTL port on the back of the board anything you type in your terminal application (such as PuTTy) should be echoed back to you.

Soldering Sanguinololu Core

Next, solder the female headers, making sure they're straight and completely seated on the PCB. Where two lengths of header strip are placed so they join in the middle, they may be fractionally too long to lie flat on the board at the join. In this case, carefully file off some of the plastic at the adjoining ends until they fit together in the space available.


 4x Female Pin Header 16 Pin

Sanguinololu 1.0 Build 4. female sockets.JPG

Solder MS1, MS2 and MS3 jumper headers. I find that it is easier to solder the 2-pin header if the jumper shunt is installed. Ensure they're completely seated and straight. Leaving the jumper shunt in place will pull the MS pins high, i.e. set the Pololu controller to sixteenth step resolution. This may not be what you want (at least initially) and you may wish to remove all the jumper shunts again before continuing.


 12x Male Pin Header 2 Pin
 12x Jumper Shunt

Sanguinololu 1.0 Build 5. microstepping jumpers.JPG

Install the led current limiting resisitor and the MS1 pull-down resistors (MS2 and MS3 have internal pull-down resistors).


 R1       1k (1.5k)        RESISTORPTH1
 R2       100k             RESISTORPTH1
 R3       100k             RESISTORPTH1             
 R4       100k             RESISTORPTH1             
 R5       100k             RESISTORPTH1             

Sanguinololu 1.0 Build 6. pulldown and led resisitor.JPG

Solder the driver decoupling caps. Before soldering, bend the leads to the side so the capacitor lays down. Mind the polarization!


 C1       100uf            CAP_POLPTH1
 C2       100uf            CAP_POLPTH1              
 C3       100uf            CAP_POLPTH1              
 C4       100uf            CAP_POLPTH1              

Sanguinololu 1.0 Build 7. decup caps.JPG

Install the thermistor high pass RC filters. Mind the polarization of the capacitors. Install the MOSFET pulldown resistors.

  • Important Note*

If you're using a Sanguinololu 1.3a here, install 100K resistors in R7 and R8. If you're using a Sanguinololu 1.2 here, do not install resistors in R7 and R8. Instead, replace them with a jumper lead - I use a clipped lead from something I've already soldered. When you're done, you should have two jumper wires: one in place of the resistor in R7 and the other in place of the resistor in R8.


 R6       10k               RESISTORPTH1             
 R11      10k               RESISTORPTH1             
 R7       100k - 1.3a only! RESISTORPTH1             
 R8       100k - 1.3a only! RESISTORPTH1             
 C9       10uF              CAP_POLPTH2
 C10      10uF              CAP_POLPTH2              
 R9       4.7k              RESISTORPTH1             
 R10      4.7k              RESISTORPTH1             

Sanguinololu 1.0 Build 8. mosfet resisitors, highpass filters.JPG

Install the dip socket and ceramic resonator. Before soldering, bend the resonator leads so that it lays down within the dip socket. It doesn't matter which way round it goes.


 Y1       16MHz 22pF       RESONATORPTH             

Sanguinololu 1.0 Build 9. dip socket, resonator.JPG

Install the two ceramic caps for the ATMEGA and the reset pull up resistor.


 C14      0.1uF            CAPPTH2
 C13      0.1uF            CAPPTH2                  
 R12      100k             RESISTORPTH1                   

Sanguinololu 1.0 Build A. resistors & filter caps.JPG

Solder the MOSFET, the large charge capacitor, reset button, and the power led. The power led's negative lead is the flat side, or shorter lead. The negative lead goes to the left in the picture immediately below.


 C12      1000uF           CAP_POLPTH4              
 S1       RESET            TAC_SWITCHPTH            
 LED1     POWER            LED3MM 

Sanguinololu 1.0 Build B. reset button, led, big cap, mosfets.JPG

ATX Power Supply Source

If you are using the ATX power supply kit, install those connectors.


 HDDPWR   5v/12v           DRIVEPWRVERTICAL                           

Sanguinololu 1.0 Build C. atx connectors.JPG

Important Note:

It has been brought to my attention in IRC (thanks Kliment & tonokip) that the 5V coming from the ATX power supply may not be as stable and at 5V as one could hope. It would be better practice here to instead of using the 4-Pin hard-drive connector use the 4-pin ATX connector and the Voltage Regulator. The 4xATX connector will still provide enough power for the board.

One could even forgo the voltage regulator and power the logic side of the board strictly by USB, the power side by 12V ATX4.

Voltage Regulator & Screw Terminal

If you are using the voltage regulator and screw terminal kit, install those parts now. Note the orientation of the LM7805. Label the screw terminal with a felt tip marker which side is + and which is -. Note - on later versions of this board the screw terminals mount at right angles to the way shown so the wire they connect comes out parallel to the USB lead.


 IC1       LM7805          VREG
 C5       0.33uF           CAPPTH2
 C6       0.1uF            CAPPTH2
 JP23     SCREW            M025MM         

Sanguinololu 1.0 Build D. voltage reg and screw term.JPG


Finally, solder your motor, end stop, thermistor, and bed/tip connectors. Optionally solder the 12v(or supply voltage) connectors on the top of the board, and the ISP 6 pin header (for programming the ATMEGA) Various parts.

Sanguinololu 1.0 Build E. connectors & isp.JPG

For speeding up the soldering of the connectors in case you use pinheaders, you can use longer strips, and just snip positions that are not used, like this:

SL11 Toprow.jpg SL11 Endstoprow.jpg

(Top strip left, endstops right)

Resulting in a board like this

SL11 Boardstrip.jpg


When you solder the pin strips onto the Pololus you will find it easiest to put the strips in the appropriate place in the Sanguinololu. Then just drop the Pololu boards on top and solder them in place. You can then unplug them later if you want.


Mechanical micro-switch endstops are recommended for their simplicity and reliability. It is recommended to wire the switch terminals Common (C) and Normally Open (NO) to GND and SIG on Sanguinololu (the two outside pins on the endstop connectors). Ensure you set Endstops_Inverting to true in your firmware.

If you are using optical endstops or proximity sensors (or other endstops that require power) you can use either 5v or 12v(or supply voltage) depending on what endstop device you want to use. This is selected by soldering a little link labeled "Stop Volt" on the back of the board. With the text the right way up, joining the left pad to the middle one gives 12v(or supply voltage); right-to-middle gives 5v. Take care not to short all three together.

Final Check


Powering Sanguinololu

Your chosen power solution will determine what kind of power requirements will be in play:

Voltage Regulator & Screw terminal kit: Connect your power supply with at least 7V and at most 30V to the screw terminal. The negative lead is the one closest to the screw hole.

ATX Power Connectors: Connect a Molex HDD cable to the connector on the right side of the board. This cable provides enough power to supply the motors as well as the on board logic chips, and a extruder heater. If you plan on powering your hotbed with Sanguinololu, or if your power supply doesn't supply enough power over the Molex plug you should also connect the ATX-4 pin connector. The ATX power supply must also be rigged to turn on when plugged in & the switch is on. This is done by shorting the !PWR_ENABLE pin to ground on the main ATX-20 pin connector. This is usually the green wire shorted to a black wire. I use a staple crammed in the socket, and use the switch on the power supply case to control system power.

Sanguinololu Firmware

You can program the ATMEGA644P with Sanguino's [bootloader] for easy firmware loading.

Sprinter is the recommended firmware for Sanguinololu.

Check the Configuration.h to ensure that Sanguinololu is selected as your board : Board 62 for Sanguinololu v1.2 and newer, board 6 for v1.1 and older.

Pin Assignments v1.2

    e-dir      (D 0) PB0  1|        |40  PA0 (AI 0 / D31) ext
   e-step      (D 1) PB1  2|        |39  PA1 (AI 1 / D30) ext
    z-dir INT2 (D 2) PB2  3|        |38  PA2 (AI 2 / D29) ext
   z-step  PWM (D 3) PB3  4|        |37  PA3 (AI 3 / D28) ext
      ext  PWM (D 4) PB4  5|        |36  PA4 (AI 4 / D27) ext
      spi MOSI (D 5) PB5  6|        |35  PA5 (AI 5 / D26) !step-enable-z
      spi MISO (D 6) PB6  7|        |34  PA6 (AI 6 / D25) b-therm
      spi  SCK (D 7) PB7  8|        |33  PA7 (AI 7 / D24) e-therm
                     RST  9|        |32  AREF
                     VCC 10|        |31  GND 
                     GND 11|        |30  AVCC
                   XTAL2 12|        |29  PC7 (D 23)       y-dir
                   XTAL1 13|        |28  PC6 (D 22)       y-setp
    ftdi  RX0 (D 8)  PD0 14|        |27  PC5 (D 21) TDI   x-dir
    ftdi  TX0 (D 9)  PD1 15|        |26  PC4 (D 20) TDO   z-stop
     ext  RX1 (D 10) PD2 16|        |25  PC3 (D 19) TMS   y-stop
     ext  TX1 (D 11) PD3 17|        |24  PC2 (D 18) TCK   x-stop
 !hotbed  PWM (D 12) PD4 18|        |23  PC1 (D 17) SDA   ext
 !hotend  PWM (D 13) PD5 19|        |22  PC0 (D 16) SCL   ext
!step-en  PWM (D 14) PD6 20|        |21  PD7 (D 15) PWM   x-step

Or in tabular format

 !step-enable-z     D26       PA5
 !step-enable-x-y-e D14       PD6
 e-dir              D0        PB0
 e-step             D1        PB1
 z-dir              D2        PB2
 z-step             D3        PB3
 y-dir              D23       PC7 
 y-step             D22       PC6 
 x-dir              D21       PC5 
 x-step             D15       PD7
 !hotbed            D12       PD4
 !hotend            D13       PD5
 b-therm            D25  AI6  PA6
 e-therm            D24  AI7  PA7
 x-stop             D18       PC2 
 y-stop             D19       PC3 
 z-stop             D20       PC4

Pin Assignments v0.7 - 1.1

 step-enable-x-y-e-z D4        PB4
 e-dir               D0        PB0
 e-step              D1        PB1
 z-dir               D2        PB2
 z-step              D3        PB3
 y-dir               D23       PC7 
 y-step              D22       PC6 
 x-dir               D21       PC5 
 x-step              D15       PD7
 hotend              D13       PD5
 hotbed              D14       PD6
 b-therm             D25  AI6  PA6
 e-therm             D24  AI7  PA7
 x-stop              D18       PC2 
 y-stop              D19       PC3 
 z-stop              D20       PC4

Microstepping Jumper Settings

Sanguinololu Jumpers.JPG

Revision 0.5 / 0.6 Info

See Sanguinololu_0.6 for assembly instructions, board files, etc.

Revision History

Rev 1.2 Rev 1.2 Updated June 15, 2011

While Version 1.1 is completely functional, there were some requests from users for pin assignment changes. Version 1.2 implements these changes. --Z-Enable is now on its own pin --PWM devices have been moved to OC0 and OC1 freeing up OC2 for internal timing --The expansion port is now a pin shorter - the Z-Enable feature ate an analog pin here.

Version 1.2 still includes the footprint for the Molex HDD connector, though you may be wise to disregard it and always install the 5V regulator as not all ATX power supplies' 5v lines are stable and clean.

Rev 1.1 Corrected silkscreen mistake. Added open hardware logo

Rev 1.0 Release revision, tighter DRC rules, and updated screw terminal footprint. Looks like there is one tiny mistake on the 1.0 board: the leftmost 5v pin on the expansion header is actually 12v(or supply voltage).

Revision 1.0 is here with only a few tiny changes from 0.7 - the screw terminal pads have been rotated so that they face the closest edge, and the design rules have become more strict to be compliant with more board fab shops. I've included gerber files in git so that you can easily have your own boards fabbed.

Rev 0.7 Added more pins to the expansion header, made I2C and SPI available for use. Combined all stepper motor enable nets into one pin.

Added footprints for voltage regulator for those wanting to use laptop power brick, etc. The vreg component footprints are hidden under the ATX power supply for space saving and to prevent both from being in use.

Enabled USB bus power for logic side.

Connected the 5v pin on the USB2TTL header so that either a: ftdi cable can power the board, or b: The board can power a bluetooth serial module (bluesmirf).

See Sanguinololu_0.6 for older revision history