Frequently Asked Questions

If you have any sales question use the Contact Us page.

All post-purchase support is handled through the FAQ’s (below) and our HobbyCNC Support Forums. Also, you can request access to the read-only archive HobbyCNC Yahoo! support group (with over 3,500 members).

Access to the Advanced Technical Support FAQ and the HobbyCNC Support Forums will be provided when your order ships. If it was not, please email brian(a) with your order information.

This FAQ and support forum are available for customers who purchase product directly from us. 2nd, 3rd, etc owners are not eligible for support here or through our Yahoo hosted group.


Sales and Ordering

Comparison of HobbyCNC Driver Products

Compare HobbyCNC products – we offer two controller boards, the HobbyCNC PRO and the HobbyCNC EZ.

The HobbyCNC PRO board can be ordered in a 3 or 4 axis variant. Our kits are easy to assemble, compact, reliable and low cost. Only one board to drive 3 or 4 steppers. Many others offer one-board-per-stepper ‘solutions’ which increases wiring complexity and takes up much more space.

Feature Comparison Matrix

 HobbyCNC EZHobbyCNC PRO 3 axisHobbyCNC Pro 4 axis
# of Axis334
4th axis upgradeNoYesN/A
Size4.8" x 3.6"
(122 x 91.5mm)
6.8" x 3.7"
(173 x 94mm)
Idle Current
Input Voltage24VDC typ
36 VDC max,
12VDC min
36VDC typ
42 VDC max,
12VDC min
(per phase)
3.0 Amps max
600ma (.6A) min
3.0 Amps max
500ma (.5A) min
1/1, 1/2, 1/4, 1/8, and 1/16
Steppers Supported5, 6, or 8 wire steppers (4 wire not usable)
Home/Limit switch
Why choose HobbyCNC

There are a lot of great reasons. Check the Why choose HobbyCNC page.

Options other than Parallel port?

Yes, there are parallel port options (not provided by me) that use USB or Ethernet. These jack-up the price considerably, though.

Generic USB-to-Parallel converters will not work. Although the overall computing demand is low, the timing of the signals on the parallel port is CRITICAL. CAM software depends not only on the signals coming out of the parallel port, but also on the timing of those signals to control the motors. These programs are operating in an effectively “real time” environment to make sure that motions happen at the right speed from multiple axes. Generic USB converters do not maintain the timing associated with the step and direction signals, therefore they are useless for CNC.

The parallel port allows for the level of direct control required for CNC. There are a couple of options. The easiest and cheapest is usually to find an inexpensive used desktop computer with a parallel port — these can often be found for $60 or less. The second option is to install an EPP compatible parallel port PCI card in your computer. These can be found for under $20 online.

Lastly, there are a couple of companies that offer USB card products with their own plugin to Mach 3 — these offload the realtime requirements from Mach to a DSP chip on the card. The are pricier than either a parallel port or a used PC, but they do offer reliable signals and faster pulse rates than a parallel port can typically offer:

Arduino, Raspberry Pi, etc

The HobbyCNC boards are compatible with Arduino, Raspberry Pi and others. HobbyCNC boards accept standard “Step and Direction” TTL level signals via a 25Pin D male connector.

The 25 Pin D connector is a reliable, robust and low-cost connector that is well suited for applications such as this.  The pin-out is designed to be pin-for-pin compatible with a standard PC parallel port, however this does not prevent connecting the board to other systems.

The actual pin-outs of the connectors are provided on each product’s page (scroll to the bottom of the page!)

One way to access these pins is to use a 25 pin D, female, solder connector (Figure 1). You can add only the wires you need.

A steady hand is needed, but this is a good, reliable and inexpensive way to get to the connections.  A “hood” or “shell” is also strongly suggested to protect the wires from the strain of plugging/unplugging (Figure 2).

HobbyCNC 25 pin D Female Solder connector

Figure 1 – 25 Pin D, Female connector, solder cup.

HobbyCNC 25 Pin D Hood

Figure 2 – hood parts (top), assembled (bottom)


Arduino name is a protected trademark of Arduino LLC.
Raspberry Pi is a trademark of the Raspberry Pi Foundation.

Shipping charges outside the United States

See the Ordering page for more details.


Basic Trouble Shooting

Do a thorough visual inspection

After each assembly step, before initial power-up and whenever you experience some problem, a thorough visual inspection will often solve 50% of the problems.

Use magnification and good lighting
Make sure you have good lighting and use some type of inspection loupe or, ideally, an inspection microscope (if you are so lucky) and carefully and methodically inspect every connection on the board – paying close attention to any adjacent solder joints (bridging).

Solder Joints
There can be many variations in a solder joint – some are mainly aesthetic (too much/little solder), some are ‘time bombs’ (cold joints) which can work for a while, then at some future date, just ‘crap out’.  Here is an excellent overview of solder joint issues by adafruit.

Solder Bridges
An unintentional ‘blob’ of solder that ‘bridges’ (connects) two pads that are geographically close together.  Most often these can be repaired with a quick touch of a cleaned soldering iron.  Egregious bridges may require a solder sucker or solder wick.

Screw Terminals
It is possible to “torque the hell” out of one of the screws and break the associated solder connection.  Look closely (use magnification)

Have the proper equipment

Having the proper equipment before attempting to assemble the PCB is strongly recommended.  At a minimum you will need:

  • Soldering Iron
  • Solder
  • Diagonal Cutters
  • Solder Sucker / Solder Wick
  • Wire strippers
  • Volt meter
  • Small needle-nose pliers
  • Something to hold the board (nice, but not necessary)

The Adafruit site has an excellent article and tutorial that is highly recommended for any newbies.



Advanced Technical Support

Assembly Tips & Tricks
This content is available to HobbyCNC customers only.
Board Assembly Instructions
This content is available to HobbyCNC customers only.
Heat Sinks
This content is available to HobbyCNC customers only.
Stepper Motor Wiring and Dimensions
Must be logged-in to see this information.
This content is available to HobbyCNC customers only.
Unused Axis
This content is available to HobbyCNC customers only.
Parallel Port Pinouts
This content is available to HobbyCNC customers only.
Checking Voltages
This content is available to HobbyCNC customers only.
No motor movement
This content is available to HobbyCNC customers only.
Missing steps – motor not behaving properly
This content is available to HobbyCNC customers only.
Power Supplies
This content is available to HobbyCNC customers only.
Home & Limit Switches

HobbyCNC PRO Home & Limit Switches Connection

HobbyCNC PRO Home & Limit Switch Hookup (PDF)


Limit Switch Wiring

HobbyCNC - Home & Limit Switches for DIY CNC or CNC Router systemLimit switches are located at the ends of mechanical travel for each axis. The idea is to shut-down the system should it try to go past its stops. Typically, there are two limit switches per axis, and all are wired in series – such that if any one switch is ‘tripped’ (e.g. “opened”), it will break the circuit and shut down the motors.

All limit switches can be wired to use just one input pin on the HobbyCNC board. You CAN use pin 11, 12, or 13. Most software allows you to pick the pin in the setup.


Routing home & limit switch wiring

Of considerable concern is how to run the wiring for the limit switches. Ideally, you want to keep them far away from “noisy” wires that are connected to the stepper motors. There is a potential for these power wires to ‘induce’ an unwanted current in your limit switch circuit which has the potential to simulate a “limit” situation. This is not a happy time.


How does a snap-action microswitch work?

Very nice YouTube video by Cecil Colvin


Q: I have a Hobby pro cnc board. I want to use magnetic proximity switches for the limit switches. They come as PNP or NPN. What on will I need for my board?
A: Our board simply provides a convenient method to connect to the DB25 connector. Our board plays NO OTHER part. Period.


Excellent discussion of home and limit switches

In section 4.5 of the Install and configuration guide for Mach3 which can be found on the MACH3 Product Manuals Page.


Spindle (relay) control
HobbyCNC PRO Output Pins, CNC Spindle Ccontrol, CNC Rrelay control

Figure 1 – HobbyCNC PRO Output Pins

To add spindle control, the HobbyCNC PRO board (Not the EZ) provides easy solder-pad access to four generic ‘output’ pins – Pins 1, 14, 16 & 17 (Figure 1). These pins are typically configured in your CAM software to control different functions – e.g. a spindle or a coolant pump.

These 4 pads are ‘courtesy’ pins that connect directly to the D connector. There is nothing else connected to these pins (as indicated by “NO PULLUPS”). So, technically, we (HobbyCNC) don’t support any type of control – we only pass these wires through from the 25pin D connector for these 4 signals. If your control software sends the proper signals through these pins, then you are in great shape.

Connecting to a spindle or pump

For simple on/off control of a pump or spindle, some type of relay (or equivalent) is required to allow the low voltage/low current of the computer to drive a high voltage/high current output. A spindle can easily draw 10 amps at 120 Volts AC. Some examples of how to do this are provided here:


Does your board support VFD or PWM?

Do you support VFD (Variable Frequency Drive), PWM (Pulse Width Modulation) or PDM (pulse density modulation)?

As stated above, the HobbyCNC board does not ‘support’ any type of output control (except the stepper motors). On the HobbyCNC PRO board, four pins are provided that will output whatever signal(s) are generated by your software.

Some videos suggested by our users

LinuxCNC Huanyang VFD, home switch, and joypad configuration

Homemade DIY CNC, How to control a Huanyang VFD inverter with Linux CNC


Support for Foam PRO and old HobbyCNC product

Foam Cutting

Check the HobbyCNC & CNC Foam Cutting page for some killer options.

The HobbyCNC FoamPro product has been discontinued and support and spare parts are no longer available.


All available documentation has been released in the FAQ “Legacy HobbyCNC Products (discontinued)“.  Available to HobbyCNC customers only.


I do not have access to schematics for these products.

Power Supplies

You must use 2 separate power supplies.
As recommended per the instructions provided with the kit:

  • The CNC board power supply of 12-24VDC 8A would be fine.
  • The wire power supply of 24 to 36VDC at 8-10A works for most applications.


  • Parallel port cable wired straight thru to connect to computer.
  • Home function is not supported.
Legacy HobbyCNC Products (discontinued)
You must be a HobbyCNC customer and registered on this website to see this content.

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