Aakar Motherboard

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Aakar Brainboard v2

Release status: working

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Release Version 2.0
CAD Models
External Link

Aakar Brainboard v2 is a modular CNC controller board based on LPC1768 Cortex-M3 chip. Due to its modular design it allows easier upgrades as per requirements and easy replacement if there is any broken part. It runs on open source Smoothie modular firmware and is targeted at 3D Printers, Laser cutters, CNC Mills, Pick and Place and other small or Mid size CNC machines.

Aakar Brainboard V2

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Source Files

Source files available at:https://github.com/jittu9954/aakarbrainboard



  • NXP LPC 1768 32-bits Cortex-M3 MCU, running at 100Mhz. 512kB Flash, 64kB RAM.
  • Drag and drop flashing : simply drop a new firmware file to the Aakar drive to update.
  • USB2 Composite device : shows to the computer as both a Serial device, and a Mass Storage device ( exposing the SD-card).
  • Ethernet.

Stepper drivers

  • 3 to 5 Allegro A4983 or DRV8825 stepper driver modules.
  • Each capable of driving bipolar steppers up to 35V and 2A(DRV8825).
  • Microstepping control of individual stepper to give greater flexibility.

Power outputs

  • Up to 3 through hole 10A, Mosfets sharing a power circuit.
  • Up to 2 Mosfets with options of regulated 12V output for Fans.
  • One Mosfet with separate power supply 20A, up to 36V.
  • One optically isolated DPDT relay ~240V,5A for driving AC loads like milling tools or vacuum pumps.
  • Regulated 5V and 12V headers.
  • Two standard servo connector powered from onboard 5V regulator.

Power inputs

  • True single input power operation by configuring jumpers(by default jupers are configured in this state).
  • Main 12-24V (Stepper drivers ) power can be connected using a 5mm screw terminal or standard 2x2 ATX cpu power connector.
  • 5V input can be taken directly from the USB cable or supplied by a 5V switching regulator installed on the board.
  • Series fused input for heated bed MOSFET with seperate power input.


  • 4 Thermistor (12-bit ADC ) inputs.
  • 6 Endstop inputs.
  • Play/Pause LED and Button.
  • Connector for Serial Graphic LCD Panel with encoder and buzzer.


  • Stepper signal pins are broken out for connection external stepper drivcers.
  • Regulated 12V and regulated 5V headers.
  • 1 SPI connectorwith selectable 3.3V or 5V vcc.
  • 1 SPI/UART connector with selectable 3.3V or 5V vcc
  • 1 I2C connector with selectable 3.3V or 5V pull-ups and vcc.
  • 1 I2C/UART connector with selectable 3.3V or 5V vcc.
  • 1 UART connector FTDI cable compatible pinout.
  • All GPIO pins broken out on headers.
  • 4 LEDs.
  • Serial graphic LCD panel with rotary encoder or push button control panel, many connectivity options.


  • SD bootloader customized for Aakar Brainboard allows drag and drop firmware upgrades.
  • Runs the highly-modular Smoothieware firmware.


  • Dimensions are 110x150mm.

More Information


Buy Aakar Brainboard


Buy Aakar LCD Panel Here



Wiring Diagram

Below wiring diagram shows a typical 3D printer configuration with 3 extruders. Similar wiring diagrams for CNC and laser cutters will be released soon. 3D Wiring aakar.jpg

Power distribution

Aakar Brainboard v2 is designed to provide a flexible power input options to different modules. Below diagram shows distribution of input power. Distribution of power can be controlled by setting two solder jumpers provided on the underside of board.

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Solder Jumper, SJ1:FAN_PWR

This jumper selects input power for FAN1 and FAN2 Mosfets. These are low power Mosfets used to power DC fans LED arrays(loads up to 5A) without heatsink.

Fan pwr jumper.jpg

12V position

In this position power is supplied form onboard 12V switching regulator that can supply up to 3A of current. It is useful when you want to drive a 12V fan but main power supply is greater than 12V.

  • NOTE: In this mode load current must not be greater than 3A. Driving loads greater then 3A will trigger over current protection.
VIN position

In this position input voltage (VIN) is directly supplied to these Mosfets. In this mode each mosfet can drive 5A of continuous current without any heat sink.


This jumper selects input power for HE1, HE2 and HE3 Mosfets. These mosfets can be used to drive extruder heaters with load current of 10A each with heatsink.

He pwr umper.jpg

VIN position

In this position in this mode input voltage(VIN) is used to drive these Mosfets.

  • CAUTION: VIN can range from 12V to 24V, higher voltage will damage the board.
VHB position

In this position Mosfets are powered form voltage supplied at VHB terminal. In this position voltage can be in range12V-36V.

Heated Bed

Heated bed Mosfet is powered from HBIN terminal. Input voltage can be in range 12V-36V and current upto 20A. This supply also has option for a fuse in series using PAD1 and PAD2.

  • CAUTION: This Mosfet can get very hot during operation do not touch with bare hands.


An onboard optically isolated DPDT relay is provided which can be used to switch AC loads at 240V, 5A. Input AC voltage is applied at IN terminal and NO and NC outputs can be used as output.

  • NOTE: This is a mechanical relay so PWM is not possible and switching frequency must not exceed 10Hz to increase relay life (Pin compatible Solid State Relay can be used as replacement for PWM operation).

Stepper Motor power

Stepper motor are powered from reverse protected VIN supply. Steppers input power can range from 12V-24V. Remaining board is powered from on board 5V switching regulator.

End Stops Power

Endstops can be powered from 5V or 3.3V by setting END_STP_VCC jumper located underside of the board.

End stp vcc.jpg

Stepper Motors

Aakar Brainboard v2 supports Pololu DRV8825, A4983 stepper modules(or any pin compatible module). Maximum 5 onboard modules can be used.

  • NOTE: Aakar Brainboard v2 can only support Bi-polar stepper motor operation. However, any uni-polar stepper motor can be used in bipolar mode

Stepper motors can be connected to the board using 3.5mm screw terminals or cheaper 2.54mm strip connectors. Microstepping can be set individually for each stepper motor by jumpers provided under each module.

Micostepping table

A4983 Module Jumper setting

A49 step table.jpg

DRV8825 Module jumper setting

Drv step table.jpg


SPI_1 Header

This SPI port is shared with SD card. Pin2 can be 3.3V or 5V powered by setting SPI1_2_VCC jumper.

Spi 1.jpg

SPI_2 Header

This Header can be configured as SPI port or A USART Port. Pin2 can be 3.3V or 5V powered by setting SPI_1_VCC jumper.

Spi 2.jpg


This I2C port can be interfaced with a 3.3V or 5V logic device, Pull ups are provided with either 3.3v or 5V pullups.

I2c 1.jpg


This Header can be configured as I2C port or a USART port.

I2c 2.jpg

  • NOTE: disable Pull-ups when using in USART mode.


This header is pin compatible with FTDI cable. This serial port is used during SPI mode to flash bootloader.

Ser 1.jpg

GLCD Panel Header

ST7565 and ST7920 controller based Graphic LCD panels can be used. Encoder with a push button, a PLAY button and a RESET button is also supported.

Glcd panel header.jpg

More info about interfacing at: http://smoothieware.org/panel

Stepper motor Header

An extra stepper motor can be added to this Header.

Aux stepper.jpg

  • NOTE: Motor supply Voltage is not supplied through this header. VCC_LOGIC is for logic supply only.

CPU Board

CPU board is the processing module of Aakar Brainboard v2. This Board has onboard mini USB port, RJ45 Ethernet port, micro SD card slot and 10-pin JTAG header.

Brain board.jpg

  • NOTE:Onboard microSD card slot and SD card slot on Brainboard v2 share same pins ,only one can be used at a time and only one of them is populated on the shipped board.

ISP button is also provided on board to facilitate ISP flashing. This button can also be used as a user button by setting a jumper. More info about flashing bootloader to the board is available at smoothieware website.

  • NOTE: All boards comes preflashed with SD bootlaoder.If you want to flash other bootloader using ISP you need to set button jumper to ISP mode

Aakar Brainboard v2

Aakar Brainboard v2 3D printed Samples

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Obtain fully assembled Aakar Brainboard v2

aakar3dp.in[1] If link not working: Drop an email for price and other enquiry [email protected]

Reference Schematics

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Aakar Brainboard v2 official manual: