3-Axis GRBL CNC stepper controller with Arduino Mega328

thingiverse

This is my take on a GRBL Mega328 3-axis stepper driver board for my CNC mill. It's designed for the new Trinamic TMC2100 stepper driver chips on a breakout board sold by Watterott-Electronics, which I really like because they're really cool - they decrease current when the motor is idle and are silent, available here [link](http://www.watterott.com/de/SilentStepStick). But you could also use other stepper-drivers like the Texas Instrument DRV8825 or Pololu A4983 if you prefer. * There's only one power-supply input (24-45 Volts) and the board uses a step down converter to generate 5V/3.3V supply for the controller. * All inputs are galvanically isolated with opto-couplers and a DCDC converter for supplying the secondary side [link](http://www.reichelt.de/index.html?ACTION=3;ARTICLE=35024;SEARCH=SIM1-0505%20SIL4), so there's no problem with EMV going into endstop cables and doing funny things to the CNC controller. * Atmel Mega328 controller with FTDI USB chip on board * Uses the really fantastic GRBL firmware for Arduino On the software side, I use [bCNC](https://github.com/vlachoudis/bCNC) as g-code sender and autoleveling platform for milling PCBs. The board and schematics were designed with KiCAD To be on the safe side, I've added a cooler for the stepper drivers. It uses a printed duct and a 40mm 5V fan. Aug-29-2015 uploaded newest Sketchup file, with an easier-to-print fan-duct and improved bottom and top enclosure parts. I have a few professional-made PCBs now (just bare PCBs, no soldered parts), so if someone's interested in those, let me know. Update! There was a stupid mistake in the FTDI (USB) section - VCC was connected to 3.3V and that caused the USB connection to fail at random times or completely fail. I fixed the PCB and schematics.