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MaKr3d Melzi controller board

all-in-one 3D-printer electronics with graphical display

About the project

This is a set of an improved version of the well-known Melzi controller board bundled together with a graphical LCD panel to allow for stand-alone operation of the printer from microSD card.

The board is an out-of-the-box electronics solution for all current reprap-type 3D printer designs with one extruder. Just connect it to your Prusa Mendel or similar printer and start printing! Thanks to its Sanginolu-compatible design it is supported by all common firmware versions. The board comes pre-flashed with a current version of the Marlin firmware and an Arduino-compatible bootloader (optiboot v5.0). That means you don't need any special tools in order to update the firmware or to change to a different one. A simple Mini-USB cable is all you need.

The LCD panel hosts an inverse blue/white 128x64 pixel graphical LCD (blue background, white pixel), rotary click encoder, buzzer and microSD slot. It is supported by the popular Marlin firmware.

FlexibleBy installing the grbl firmware this board can be used for small CNC machines with up to four axes as well. All three power outputs are PWM enabled and designed for driving inductive loads. They are capable of directly driving a spindle motor or a coolant pump or powering the cutting wire of a CNC foam cutter.

Why another controller board?

This set is an all-in-one solution, ready for use and with no need for any soldering or crimping. The already well-designed original Melzi board is improved by adding some of the best features of other common electronics like the Gen7 and RAMPS. The motordrivers are exchangeable now, in case an experiment went wrong. Furthermore the design was optimised from the ground up for low manufacturing costs.

This board is designed to be hackable. All interesting signals are available at contact pads in an easy solderable standard 2.54mm pitch and they are clearly marked on the silkscreen of the PCB. It uses the MCP2200 USB-UART converter for connecting to the PC. This converter offers 8 GPIO lines, programmable via USB from the PC using an existing software library. All of these signals are easily-accessible as well.

Many of the existing electronics solutions focus on the build-it-yourself idea. Building everything from scratch, maybe even on a self-etched PCB, is great for the educational experience and the pride of owning a really self-made machine, but hardy includes financial advantages, if any. In most cases sourcing the required parts in single quantities in Europe is more expensive than purchasing a complete, fully-assembled and tested unit.

One of my goals in producing and selling this board is to support the incredibly active and creative Maker community, by helping to improve the price and availability of the electronic components. I used to work for an electronic manufacturing service company in Asia and took advantage of my former professional experiences and contacts to offer a complete electronics set at an affordable price.

The MaKrPanel

This is a separate module with a graphical LCD, 128x64 pixels, backlight, a microSD slot, a rotary encoder with switchbutton for user interactions and a buzzer. It connects to the mainboard by two cables, one 10pol and one 6pol. The 6pol cable connects to the standard 6pin Atmel-ISP connector and the 10pol cable connects to the 8 bit extension connector. It is possible to adapt this module to other boards, but you will probably have to modify the wiring of the 10pol cable.

The panel can be mounted on top of the mainboard using the included standoffs or detached from the mainboard for installation in a different location.

The stepper motor drivers

The set comes with four stepper motor driver modules included. They are compatible with the popular A4988-based Pololu driver modules. But unlike many others, they are shipped fully assembled and there is no contact pin soldering required.

They are capable of driving currents up to 1.5A per phase. For most printer designs and typical NEMA17 motors currents in the range of 0.3A to 0.75A are required. Fine current adjustment is easy as the current-set-potentiometer utilizes the maximum 270° rotational range for the full range. Many other modules are much harder to adjust as they use only 90° or even less for the full current range.

Technical data​​

  • CPU ATmega1284P, 16MHz: 128kB flash, 16kB RAM, 4kB EEPROM
  • 4 exchangeable A4988 motor driver modules, Pololu-compatible, 1.5A per phase max.
  • 3 PWM capable power-MOSFET outputs with indicator LEDs (red), 10A/5A/1A resp., suitable for inductive loads.
  • 3 digital inputs, 3-pole connection (GND, signal, +5V, allows for mechanical, optical or magnetic endstops)
  • 2 analog inputs (temperature measurement with thermistors)
  • Detachable panel unit
  • microSD slot
  • Graphical LCD with backlight, 128x64 pixels, controller ST7565R, SPI, blue/white
  • Rotary encoder (24 clicks/round) with switchbutton
  • Buzzer
  • Mini-USB connector, MCP2200 UART converter with 8 freely-programmable GPIO lines and TX/RX indicator LEDs (blue)
  • Reverse polarity protection on DC input (almost lossless, not only a diode)
  • Fuse-protected DC input, 8-30V, 15A max.
  • DC/DC converter for 5V generation - no need to modify voltage range resistors if using voltages other than 12V.
  • Power indicator LED (green)
  • Screw terminals for all external connections, no soldering or crimping required
  • Jumper-selectable stepping mode: full, half, 1/4, 1/8, 1/16
  • One programmable yellow LED, very helpful with the Arduino bootloader.
  • dimensions 220 x 58 mm²
  • A stylish blue/golden PCB ;-)

What is included?​The full kit contains: The fully-assembled mainboard, four motor driver modules, the MaKrPanel, the  cables required to connect the panel to the mainboard, and mounting hardware (4 metal standoffs M3x30, screws, washers, and spring washers)

Please note: You will need a mini-USB cable to connect with your computer, this is not included with the board.

The MaKrPanel includes: the panel itself of cause, the needed cables to connect the panel with the mainboard (2 cables, 6pol and 10pol), and mounting material (four metal standofs M3x30, 4 screws, washer, spring washer)

What are the funds for?

You are helping with the product introduction, even in two ways at the same time: The first sales will help with the production setup costs. Besides, maybe even more importantant, you are voting for the right proportion between the different options full set/board only/panel only.

About the project owner

I am a freelance electronics and computer engineer with 14 years professional experience and another 14 years of private experience with embedded systems design and programming. I used to work as the R&D manager of an electronics design and manufacturing services company in Thailand.

Last year I got hooked on the idea of building my own 3D printer, and that project brought me into contact with the incredibly active Maker community. As I delve further into this community, it surprises and impresses me over and over again. There are so many great ideas out there!

After finishing this campaign, I am planning to sell these (and some other) parts commercially. Check out my website at


  • Is the shipping cost included in the prices?

    No, it's not. In most cases the first article is 3,80€ for Germany or 10€ for the other EU countries and 2,00 to 2,50€ for additional items. The actual shipping cost will be shown before you enter your payment data. If the numbers you see are very different from what you are expecting, please contact me to fix the problem.

    Last updated: 6 years, 1 month ago

  • Which countries do you ship to?

    The actual shipping will be handled by They support shipping to these 27 EU countries:

    Austria, Belgium, Bulgaria, Cypress, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden and the UK.

    I would like to ship worldwide via as well, but so far I haven't figured out how to manage the import into the US without being a US citizen or a US company. If you know somebody who could tell me what to do please contact me right now!

    Last updated: 6 years, 1 month ago

  • Do I get an invoice?

    Yes, complete with address, VAT and tax ID. It is a regular purchase and the boards comply with the usual EU requirements (RoHS, WEEE registration, package waste registration)

    Last updated: 6 years, 1 month ago