DIY 2DOF Motion Simulator – Inspired by Mantis FS2

Hi everyone,

This is my first serious attempt at building a 2DOF motion simulator with electronics. In the past I experimented with a simple PVC frame build, but now I’m stepping up to something closer to the excellent F1 Style 2DOF Mantis Simulators FS2.

At the moment most of the parts are just starting to arrive. I’m still waiting for the motors and hall sensors, and I need to buy the power supply and some structural pieces. Once the motors are here I’ll start drawing and assembling the frame.

Planned hardware
• 2x 24V 440W 1:60 worm drive motors
• 2x BTS7960 43A H-Bridge Motor Driver (I'm also waiting for sabertooth driver for upgrade)
• Oubit 12-bit Hall sensors 360°
• Arduino Uno R3 (I think)
• 24V PSU (to be purchased)
• Aluminium frame, 40x40mm , almost identical to the Mantis FS2 design

Notes
• Being in Argentina makes sourcing parts more complicated, so progress may be slower.
• This is my first time working with electronics at this level, so I’ll be learning as I go.
• The goal is to replicate the Mantis FS2 style as closely as possible.

Closing
I’ll keep updating this thread as parts arrive and the build progresses. Any advice from the community on motor control, power supply choices, or hall sensor integration would be greatly appreciated.

For now, I’m still reading through the documentation available on the site, so I’m aware that most questions are already covered there.

I want to add the links to the items so you can see where I bought them, but I think I haven't enough posts yet to use this feature maybe (?), also with the link to mantis post

DM me and I'll send you the STLs for the 3D printed parts

Some parts have arrived over the past few days.

Now I'm waiting for the universal U-joint, the tool to cut the aluminium, and some other accessories. I think I will start building in the next few weeks.

I wouldn't use a gear transmission for the sensor because of the backlash. If you use a gear transmission, you'll need to use a spring-loaded gear like the one in the Vernier mechanisms of old receivers. A gear belt system is more preferable. For example, GT2. Gears can be designed in OpenSCAD and printed on a 3D printer. I also gave up on the BTS7960 drivers because of their low reliability. I bought a 100A driver from AliExpress.

Thanks for the advice! I think I’m going to give the gears on the hall sensor a try — I can always upgrade later.

About the drivers, I bought a Sabertooth 2x32 right after the BTS, so in the end I’m going to use the Sabertooth.

While not the best design, the gears on the pot work fine - the mounting holes are slots so you can push together to get a good mesh.

And you can't go wrong with the sabertooth, they're bullet proof.

Hi there! Work in progress!

I'm finishing the Arduino box now. I'm not fully sure if the connections are 100% correct, but I tried the motors without the resistors and they worked fine.

I'm still thinking about the best place for the fuses, but for now I'm going to trust the main C13 fuse

About the frame, I'm waiting for the levers and pot brackets from @early_m, but in the meantime I will build the structure using 3D replacements just for testing.

Looks great Ivangillig, I would recommend grounding the metal housing to the ground of your PSU if you haven't already (not the negative). What PSU will you be using, just curious? Did you already buy the simtools software, its a shame its not free anymore for DIY'ers.

As for the fuses. I have put a 60 amp midiOTO right after the PSU and 2 individual 30 amp fuses after each power port on the sabertooth in between each motors.

I would suggest to keep them in sight. I put mine on the bottom of a platform and would be pretty annoying to change if one decides to go.

You'll most likely need to ground pin 8 and set the correct baud rate in Simtools with a clone Uno - if you have erratic motor behaviour this will be the solution

thanks! I'm using the Mean well SE-1500 which haven't a ground output, I assume that should use the input ground

I already bought the simtools... I almost ended using flyPT, but I have not enough energy to spend on this... I prefer something more plug and play haha

Thanks! I'm following this tutorial:
https://www.xsimulator.net/communit...ial-pid-motor-driver-sketch-w-softstart.9277/

and doesn't mention the pin 8, just pin 13 and ground from arduino to sabertooth, do you refer to another setup config??

At the moment, I test just one motor over my desktop and looks good, it moves a little erratic, but I'm 100% sure that it's for the jumps on the hall sensor (I use the 3d version of bracket)

See this post

https://www.xsimulator.net/community/threads/help-to-diagnose-2dof-crash.13639/#post-182883

ahhh I understand now, I will connect the pin 8 as you said, thanks!

Hi everyone, I made a newbie mistake, the metal enclosure I used for the electronics caused a short circuit (apparently the terminal blocks were grounding against the case) and my Arduino got fried. That’s not a big issue since I have spare boards.
The real problem now is that my Sabertooth no longer outputs any current to the motors. The green LED stays solid as if it’s in OK status. In SMC3 I can see the sensor feedback (360° Hall sensor) and I also see variations in what should be the current readings. However, when I measure the motor outputs directly with a multimeter, I get a permanent 0 V.

Has anyone experienced something similar? Any ideas on what could be happening or how to confirm if the Sabertooth is damaged?

Thanks in advance for any help!

Have you connected the sabertooth to your pc and used describe to check if it communicates?

Yes, I have connected the Sabertooth to my PC and used Describe. The unit communicates correctly: the software detects it, the green LED stays solid, and I can see sensor feedback and current variations in Describe/SMC3. However, when I measure the motor outputs directly with a multimeter, the voltage remains at 0 V regardless of the commands sent.

This makes me think the logic is working but the power stage is not delivering any output

Fully assembled and test both M1 and M2 outputs with a motor. If it doesn't work dimension engineering have very good warranty and rma...