FAQs
I have tried to answer as many questions as possible here but some maybe amiss. It will be relatively easy to add more questions and answers later however if they become, well, frequently asked.
No. SimTrim can provide synchronisation on any axis of any joystick device you currently have plugged into your computer. You can even use a spare lever on your throttle quadrant if you wanted. Although with such a limited range of motion, this should be considered a temporary solution. Any other analogue trim wheel type device would be a better choice, but even then, you do not need to stick to any specific brand or make to use SimTrim.
No. You can assign the TWP in flight simulator control options to your elevator axis trim, or any other axis control for that matter, the same as any other joystick device and it will work as expected. Without SimTrim you will lose the synchronisation benefits, but SimTrim is not a requirement.
It doesn’t matter if SimTrim is started before or after flight simulator starts. Either way SimTrim detects when flight simulator is active and only performs its duties while flight simulator is running. The same is true if you want to make assignments and sensitivity changes. You can do it either before or “on-the-fly”.
Not currently but maybe in the future. I still have a few plans for SimTrim including adding some new features before I get to that stage.
The firmware for the Arduino is open-source, yes, and available from the resources page. The model files are also open-source and available from Printables.
The model files are quite simple in the fact that it is only a wheel. There is room for extra buttons and switches and plenty of spare pins on the Arduino, so feel free to modify or remix it as you want.
Width=85mm(~3.35″), Height=140mm(~5.5″), Depth=104mm(~4.1″)
The model will most likely be improved later but I will try to keep the dimensions the same as it is now. I know that it is quite import to keep TWP small (especially the width) when trying to fit it between other devices on your desk.
A digital wheel outputs a series of button pushes depending on which direction you turn the wheel and by how much. For example, rotating the wheel clockwise by 50o might send 7 button 1 presses, the same as pressing the appropriate key on the keyboard 7 times.
An analogue wheel has a continuous range of values which are output according to the angle the analogue wheel is at. This can be compared to a throttle lever or steering wheel.
Whereas an analogue wheel knows and sends its current angle, a digital wheel has no knowledge of its current angle. Instead, just incrementing or decrementing the in-sim wheel position by sending appropriate button pulses.
It doesn’t. SimTrim uses DirectInput to detect all joystick devices on your system. Since TWP is a joystick type device it gets detected too. So TWP talks one-way with SimTrim. SimTrim Communicates both ways with flight simulator, however. This way, the firmware on TWP can remain relatively simple since it does not need to send and receive to and from your PC, you can use any joystick device with SimTrim and you can use TWP as a regular joystick if you so wish. It is SimTrim which does all the communication with the flight simulator effectively.
SimTrim has only been tested with Microsoft Flight Simulator 2020 and probably will not work in its current state with other simulators. That is because the interface provided by Microsoft for interacting with MSFS2020 is different to the ones provided by any other sim. All this could change in the future however as I plan to support more and more simulators.
TWP, i.e. the wheel itself should work on any simulator as it can be mapped as any other joystick device. You will not get the synchronisation provided by SimTrim but it will work as a standard joystick.
Any Arduino based on the ATmega32u4 should work fine with the firmware. This includes the Arduino Leonardo and Arduino Micro but will not work with devices such as the Arduino UNO and Arduino Nano.
I used an Arduino Pro Micro Leonardo compatible board because of its small size, and I have designed the model around this. There are no screw holes on this board so mounting was an issue. I settled on creating a small recess for this board in the base of the model which holds the board in place. But a full-size Leonardo will work fine also. It would be too large to fit in the TWP model, so I would only use the full size Leonardo for testing purposes and without the lid.
Another note worth mentioning is that the Pro Micro I used is a USB type C version. The same boards with the USB micro connection work the same but I found this connector broke off very easily whereas the type C variant is a lot more secure. For this reason, the Arduino Pro Micro Leonardo USB type-C is the one I recommend.
There is nothing wrong with this, the only problem is that Windows and Flight Simulator will see your device as “Arduino Leonardo” and not “Trim Wheel Pro”, but it will function fine either way. It might be a bit confusing however when you have multiple Arduino Leonardos attached to your system and/or you don’t know what each one’s purpose is.
If you want to change the name of your device and assuming you are using the Arduino IDE 1.x, you will need to change boards.txt. I have found a gist on github which provides useful instructions: boards.txt gist
Please make sure you copy boards.txt to some other name as backup before attempting this though.
