Sim Hub Gear Indicator

SimHub provides many useful & cool features including a gear indicator that uses an 8×8 matrix. This is a great project for anyone getting started with SimHub and/or 3DPrinting.

I’m providing two version here – a vertical model and a more bullet shaped version. Depending on the matrix you are able to get and where you would like to mount it on the rig one or other will work for you.

You can download my models from Printables or get in touch if you would like them printed for you.


In addition to the printed parts I used the following.


  • 6 x M3 x 5mm x 6mm Heated Inserts.
  • 2 x M3 6mm Cap Head Bolts
  • 4 x M3 25mm Cap Head Bolts


  • 4 x M3 x 5mm x 6mm Heated Inserts.
  • 6 x M3 50mm Cap Head Bolts
  • 2 x M3 45mm Cap Head Bolts


For the vertical model I used an AZDelivery MAX7219 8 x 8 Dot Matrix MCU 64 LED which worked brilliantly out the box although as they have packaged the chip alongside the matrix and it comes with a header attached it makes it quite long. As a variation and for the Bullet version I sourced some Youmile 2Pack MAX7219 8×8 Dot Matrix which has also worked very well.

If you are building the bullet version make sure you insert the matrix before adding the heated inserts as these can fix the matrix into place. If the matrix still moves a little after then hot glue can be applied. Same is true for the Arduino but I advise testing first!


For the wiring we are basically following the standard SIMHUB guide which you can see here I have provided two sets of cable colours as the matrix often arrive with a ribbon cable of which you may have one, other or both available.

Pin D3Pin D4Pin D55VGND
DATA (DIN)Blue | Orange
CLOCK (CLK)Grey | Brown
LOAD (LD or CS)Purple | Yellow
VCCWhite | Red
GNDBlack | Green

SimHub Setup

It is pretty easy to configure SimHub. The only points to note are that only one matrix is supportedby SimHub and to rotate the display you have to change the setting under Arduino’s Display and alerts menu and not the connected Arduinos Hardware option.

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