Setting up an Arduino with SimHub, step by step

Before you start

• A supported board. Uno R3, Nano v3, Mega, Pro Micro 5V/16MHz or Leonardo. Not an Uno R4 — see the board list.
• A USB cable that carries data. Charge-only cables are the single most common reason a board is never detected.
• The right driver. CH340G for most clones, FTDI for genuine boards and better clones.
• Everything else unplugged. Specifically, every other Arduino. This is a safety measure, explained below.

Triple-check the port. Flashing the wrong device cannot be undone. The official guidance says to "always triple check that the serial port used to flash is the one of your target device", and that wiping the wrong device "can't be reverted!" The simplest protection is to have only one board connected while you flash.

The wizard

1. 1

   Open the Arduino setup tool

   From SimHub's Arduino section in the left menu. On first use it offers to download the Arduino toolchain — accept, it is a one-off.

2. 2

   Give the device a unique name

   Not optional if you will ever run more than one Arduino. Two boards sharing a name is a configuration that cannot work, and the symptom is that one of them simply never appears. Name it for what it does — revbar, gearmatrix — rather than arduino1.

3. 3

   Tick the features and set quantities

   RGB LEDs, matrices, 7-segment displays, buttons, encoders, motors, servos. Quantities matter — how many LEDs, how many digits, how many buttons — because they determine the pin and memory budget.

4. 4

   Assign the pins

   The step that decides whether this works. See below.

5. 5

   Pick the COM port and board type

   The port from Device Manager, and the board matching what you actually have. An Uno clone is an Uno; a Nano clone with an ATmega328 is a Nano v3.

6. 6

   Upload

   SimHub compiles and flashes. If it is refused, see the 15-second lock below.

7. 7

   Save the profile

   Optional and worth doing. The saved profile lets you come back and edit the configuration later instead of rebuilding it from memory.

Pin assignment, properly

Every pin must be unique, and the defaults can collide. Tick two features and each arrives with its own default pins — which are not guaranteed to differ. A duplicate assignment stops the firmware building, and the error message does not always name the two features that clashed.

How to avoid it entirely:

1. Plan on paper first. List every feature and how many pins it needs before you open the wizard. On an Uno you have around 20 usable pins and they go quickly.
2. Assign explicitly rather than accepting defaults. Go through each feature and set its pins yourself, in order, so you can see the whole allocation.
3. Keep a record. The saved profile does this for you, and a year later it is the only thing that will tell you why a wire goes where it does.
4. If you run out, use a Mega. That is the main reason to choose one over an Uno, and it is cheaper than redesigning.

Some pins have fixed roles — the serial pins are used for USB communication, and some features require pins with specific hardware capability. The wizard will not offer you a pin that cannot do the job, so if an option is missing, that is why.

The 15-second upload lock

Uploading is locked 15 seconds after the board is plugged in. This is deliberate — it protects against unwanted firmware wipes. Either send the upload-unlock command, or simply replug the board and upload promptly.

It is worth knowing because the symptom looks like a failure. A board that refuses an upload is usually not broken and usually does not need a different driver; it has been connected for more than fifteen seconds.

Build and flash, or build and export

Build and flash

Compiles the firmware, saves the configuration and uploads it straight to the device. What almost everyone wants.

Build and export

Compiles and exports the source as a ZIP containing all dependencies, for manual customisation. The route if you want to modify behaviour beyond what the wizard exposes.

If you take the export route, be aware of what it requires:

• A legacy Arduino IDE 1.8.x — not the current 2.x.
• Edits to boards.txt in hardware\arduino\avr, using content supplied inside the export.
• Your own maintenance from then on. SimHub will not update a firmware you have customised.

For most people the wizard covers everything, and exporting is a decision to take on a maintenance burden in exchange for control.

After the upload

SimHub should show the device under its name. If it does not:

1. Check the COM port has not changed. Windows can reassign it, and SimHub needs a restart when it does.
2. Check the device name is unique against every other Arduino you have configured.
3. Check scan settings — SimHub can be told to exclude ports, and an excluded port is invisible.
4. Work through Arduino not detected, which is ordered by how often each cause is actually it.

Once it appears, the configuration side begins — LEDs, the LED editor, matrices — and that is where most of the interesting work is.

Common questions

Sources

• SimHub wiki — Arduino setup
• SimHub manual — firmware builder, getting started
• SimHub manual — manual compilation and customization

Related guides

• Arduino hubSupported boards, power wiring, and what SimHub can drive.
• Not detectedCables, drivers, COM ports and the generic CH340G problem.
• RGB LEDsThe most common thing to build, and where the configuration work is.