Connecting Grbl
This wiki is intended to provide various instructions on how to connect to grbl in various ways. Please feel free to contribute more up-to-date or alternative methods.
First, to connect your stepper motors to Grbl, you'll need some stepper motor drivers to power the steppers and connect your driver inputs to the Arduino controller pins. There are number of drivers that can to do this, as fully pre-built, partially pre-built, or completely DIY. There are some examples later down the page. The stepper drivers will need to share the stepper enable pin (D8) to their respective enable pins, while the direction and step pulse pins (D2-D7) will need to be connected to their respective pins on the drivers. Just make sure that all of your drivers and the Arduino share a common ground (star grounded with your motor driver power). This is about all you'll need to get started.
Afterwards, once you decide that you're ready or would like to enable homing and/or hard limits, you'll need to connect a normally-open limit switch to each of the limit pins (D9-D11). Homing and hard limits use the same switches. These limit pins are already held high with an internal pull-up resistor, so all you have to do is wire them to ground. So when you close a switch, the switch will pull the limit pin to ground. If you'd like to have hard limit switches on both ends of travel of an axis, just wire two limit switches in parallel to the axis limit pin and ground. That's it! Just make sure you have the switches installed before attempting to perform a homing cycle.
(Also, if you tend to crash into the hard limits often, you may want to install a normally-close switch in series with the shared limit switch ground. This will allow you to physically disconnect the limit switches so you can have Grbl perform a move without tripping the hard limits again.)
As of Grbl v0.8, there are pin-outs of the cycle start, feed hold, and reset runtime commands, so you can have physical control buttons are your machine. Just like the limit pins, these pins are held high with an internal pull-up resistor, so all you have to do is connect a normally-open switch to each pin and to ground.
If you have a desire or need for spindle or coolant control, Grbl will toggle these output pins (D12, D13, A3) high or low, depending on the g-code commands you send to Grbl. Since these are all application dependent, we'll leave it to you on how to control and use these for your machine.
Last Updated: 2012-01-29 by Atrixium.
This is a fairly straightforward interface for a 3 axis machine.
The 'step signal ground' for each EasyDriver is connected together and tied to the GND pin of the Arduino. Do not confuse this with the motor ground or any other ground connection on the EasyDriver!
The 'Step' pin for the X,Y and Z axes is attached to digital pins 2, 3 and 4 respectively.
The 'Dir' pin for the X,Y and Z axes is attached to digital pins 5, 6 and 7 respectively.
Big Version
Fritzing File
EasyDriver Website
Last Updated: 2012-02-21 by aldenhart.
grblshield - plugs on to arduino for 3 axes of motor control - up to 2.5 amps per winding. Drivers are thermally protected against overcurrent and are therefore extremely resistant to burnout or failure.
Last Updated: 2012-02-03 by edwardrford.
buildlog.net arduino stepper shield - pololu driver carrier arduino shield for 3 axes of motor control. Replaceable drivers in case of damage.
- DANK Last updated 2/2011.
- Connecting Grbl to an H-bridge Driver