The board you bought won't work
Last updated · SimHub 9.11.22
Four boards are recommended for SimHub: the Arduino Uno R3, the Nano v3 with an ATmega328, the Mega with an ATmega2560, and the Pro Micro 5V/16MHz or a Leonardo — clones of all of them are fine. Three things are not. The Uno R4 is explicitly not supported, so the newest Uno on the shelf is the wrong one to buy. WAVGAT boards are fakes built on chips SimHub does not support. And boards sold as a Nano that carry an ATmega168p rather than an ATmega328 will not work either. Separately, a counterfeit CH340G serial chip — the giveaway is an unlabelled chip — causes its own driver problem. One caveat on an otherwise good choice: on the Pro Micro and Leonardo some features including the tachometer are unsupported, because of a library incompatibility.
This is a buying page as much as a troubleshooting one. Every item here is cheaper to avoid than to diagnose, and two of the three fakes are sold under the correct product name.
The boards that work
| Board | Chip | Notes |
|---|---|---|
| Arduino Uno R3, or clone | ATmega328 | The default answer. Note the R3 — the R4 is not supported. |
| Arduino Nano v3, or clone | ATmega328 | Small and cheap. Check the chip, not the name — see below. |
| Arduino Mega, or clone | ATmega2560 | For builds that need a lot of pins: big LED arrays, several displays, a large button matrix. |
| Arduino Pro Micro 5V/16MHz, or clone | ATmega32U4 | Native gamepad support, so buttons appear to games directly. Some features including the tachometer are not supported here. |
| Leonardo, or clone | ATmega32U4 | Same capability and the same tachometer caveat as the Pro Micro. |
Why the Pro Micro is worth the caveat. Boards built on the ATmega32U4 can present themselves to Windows as a gamepad, so buttons and encoders are seen by the game itself rather than only by SimHub. On an Uno or Nano, the inputs exist only inside SimHub. If you are building a button box that games must see, this is the family you want — and the tachometer limitation is irrelevant to a button box.
The three that waste an evening
- Arduino Uno R4
- Not supported. It is the newest Uno and the obvious thing to buy, which is exactly the problem — a shop's search for "Arduino Uno" often puts it first. You want the R3.
- WAVGAT boards
- Fake Arduino boards built on chips SimHub does not support. They are sold as Arduino-compatible, they are cheap, and no amount of driver work will make them work here.
- ATmega168p sold as a Nano
- The listing says Nano, the board says Nano, and the chip is wrong. Read what is printed on the chip itself: you want ATmega328.
The unlabelled chip. Counterfeit CH340G serial chips are the other common fake, and the tell is that the chip carries no marking. These often work at first and then break after a Windows driver update — the board stops being programmable by SimHub and by the Arduino IDE, and Device Manager shows "CH340" rather than "CH340G". That has its own specific fix, on the Arduino-not-detected page.
Powering it, once you have the right one
USB power is enough for most builds. Add an external 5 V supply when consumption goes above roughly 500 mA, which in practice means any meaningful number of addressable LEDs.
There is one wiring rule that matters more than the rest, and it is stated flatly in SimHub's own documentation:
"Don't connect the 5v to the arduino 5V" With an external supply, connect its ground to the Arduino ground and to the components, and its 5 V to the components only — not to the Arduino's 5 V pin. The Arduino keeps its USB power. Getting this wrong means two supplies fighting.
And the least glamorous cause of all: bad solder joints are behind most disconnects and display faults. If a build works when you press on it, that is a joint, not a driver.
Common questions
Does SimHub support the Arduino Uno R4?
No. The Uno R4 is explicitly not supported. Buy the Uno R3, or a clone of it — this catches a lot of people because the R4 is the newer product and often appears first in a shop's listings.
Which Arduino should I buy for SimHub?
An Uno R3 or Nano v3 for displays and LEDs, a Mega if you need a lot of pins, and a Pro Micro or Leonardo if you want the board to appear to games as a gamepad. Clones are fine; the chip is what matters.
What is a WAVGAT board?
A fake Arduino built on chips SimHub does not support. They are sold as Arduino-compatible and they are cheap. There is no fix — the chip is wrong.
My Nano does not work. How do I check it is genuine?
Read the chip. A Nano v3 should carry an ATmega328; boards sold as Nanos with an ATmega168p are common and will not work. Also check the serial chip is a marked CH340G rather than an unlabelled counterfeit.
Why does my tachometer output not work on a Pro Micro?
Some features including the tachometer are not supported on the Pro Micro and Leonardo, because of a library incompatibility. It is not a wiring fault. Use an Uno or Nano for a tacho gauge.
When do I need an external power supply?
Above roughly 500 mA, which in practice means any real number of addressable LEDs. Connect the supply's ground to the Arduino ground and its 5 V to the components only — not to the Arduino's 5 V pin.
Everything works until I touch the wiring.
A solder joint. Poor joints cause most of the disconnects and display faults in these builds, and they are intermittent in exactly this way — a fault that responds to being pressed is mechanical, not electrical.
Sources
Related guides
SimHub is developed independently by Wotever and is not affiliated with OESimRacing. This page was checked against SimHub 9.11.22 on 4 August 2026; where the interface has moved on since, the version stamp tells you how far. More on what SimHub is and what it costs.