3-Axis GRBL CNC stepper controller with Arduino Mega328 by uli

Last crawled date: 3 years ago

This is my take on a GRBL Mega328 3-axis stepper driver board for my CNC mill. It is designed for the new Trinamic TMC2100 stepper driver chips on a breakout board sold by Watterott-Electronics (which I really like, because they are really cool (they decrease the current when the motor is idle, and they are silent =;) available here link ).
But you could also use other stepper-drivers like the Texas Instrument DRV8825 or Pololu A4983 if you like.
There is only one power-supply input (24-45 Volts) and the board uses a step down converter to generate the 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 no problems with EMV going into endstop cables and doing funny things to the CNC controller.
Atmel Mega328 contoller with FTDI USB chip on board
uses the really fantastic GRBL firmware for arduino
On the software side I use bCNC as g-code sender and autoleveling platform for milling PCBs.
The board and schematics where designed with KiCAD
To be on the save side I have 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 a easier to print fan-duct and a improved bottom and top enclosure parts.
I have a few professional made PCB's now (just the bare PCBs, no soldered parts), so if somebody is 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 completly to fail.
I fixed the PCB and schematics.