Another compact 2dof - seat mover

After weeks of reading various threads, I’ve finally decided this project is worth pursuing and have already ordered most of the parts. Many threads lack detailed guidance for beginners like me who have no experience with hardware, electronics, or programming. My goal is to provide more in-depth details than those other threads—especially since I spent considerable time researching even small items like which bolts to use.

I’ve decided on the following components:

• 4040 aluminum extrusions
• 1× Arduino Uno R3 clone
• 2× IBTS 7960 clones
• 2× 90° Hall sensors
• 2× 24V 250W 75RPM wheelchair motors
• 1× inexpensive power supply (0–24V, 50A, 1200W)

I read in one thread that a 90° Hall sensor provides four times the resolution of the more common 360° sensor, so I opted for it since I won’t be using more than +/-40° anyway.

If I understand correctly, a 1:1 pulley ratio is required. This means one pulley would be 40 teeth with a 17 mm bore and the other also 40 teeth but with a 6 mm bore. I guess a 120mm belt?

I’m wondering if 3D-printed pulleys would work well, or if I need metal ones?

Also, why is it considered better to use 90° or 180° Hall sensors instead of 360° ones? If I understand correctly, you could utilise the full resolution of a 360° sensor with a 3.5:1 pulley ratio, since it’s the ratio between the pulleys that ultimately matters, not just the sensor resolution.

Finally, I’ve decided on a 50 mm lever to maximise torque. This design is the most compact I’ve seen so far, and I’m hopeful that the motors will deliver enough power. I’m also considering what type of aluminum to use for the levers—likely something stronger than 1050 to be safe.

My simcalc data.

The idea of Hall 90st sensors is wrong , you will easily exceed the values read from the movement of the motor and shut down the motor, buy a standard Hall 360st sensor its resolution is sufficient, do not buy an IBT-2 bridge at 24V they are easily damaged, buy a controller https://www.xsimulator.net/community/threads/reasonably-priced-100a-motor-controllers.17638/page-5 tested works without a problem, zebatki you can print , I have a design of zebatki without a belt, it works properly for a few months, unfortunately my computer died temporarily, I will try to post stl files as soon as possible

I bought almost everything already.

I have 4 cloned ibt2s and 2 cloned arduinos. I saw a lot of people had problems with them but I will give it a try. Hopefully it will work

But I will buy the 100A driver as well just in case. I need just one?

Below is what I have in mind for IBT 2s. They will be cooled by strong 40x40 pwm fans 12w each. I've got a pwm fan controller which will cool them based on temperature. And a step down power converter. I'm planning to use the main power supply for them.

Regarding the hall sensors I'm still considering what to do. Please share your stl files, maybe it will give me new ideas

100A driver 1 for two motors

Thanks a lot for sharing the stl files and photos! I like your gears approach a lot

I've received more components, so had the chance to create the frame and attach the motors.
For the frame I used:
m8 16mm bolts
40 series corner brackets
small 1mm washers
propshaft flanges
propshat universal joint

To attach the motors I used:
3d printed mounts
m8 25mm bolts
m6 35mm bolts

For levers:
m6 20mm bolts
m8 30mm bolts

Wasn't sure what aluminium to use for levers so opted for the strongest I could find which was aluminium 6082 in 10mm.

I updated the simcalc data and I think I will not need more than 30 degrees up and down. I will keep the initial design of the 90 degree hall sensor with 1 to 1 pulleys for now.

The next step will be wiring all the electronics with an emergency stop if things go wrong.

@Attyla.pl I was wondering if any cooling is needed for the 100A driver? Are you driving the motors at 24v?

Some time the 100A controller worked without cooling, out of precaution I installed one 12cm 12V fan with a rest of the regulator with 24V>12V.
Yes motors work on full voltage 24V

I've attached the lower 2dof frame to the Gt Omega Apex rear seat frame.
Then, I've done all the wiring with a kbpc5010 bridge rectifier and two 15A fuses.

Lastly, I've done some testing with SMC3 tool and it was a total disaster.

I'm certain one of the 90° hall sensors is broken. It moves from 0 to 5v in around 5-10° movement. The other one works fine.

On my first try with smc3, there was a slight movement from one motor. Anything I tried I couldn't make the motors work.

I then connected the other two ibt2's I had and got a 1 sec movement from the same motor as well. After that nothing is working.

I centered the working hall sensor to 2.5v before the second test.

I double checked that I uploaded the right sketch and run it in mode 2.

I'm confused if I burnt all four ibt2's. But how? I used 16v on the power supply

Now, I'm not sure what to do next? I will try to use the other arduino I have but doubt it will make a difference.

I guess I could try to get a second power supply. Maybe something is wrong with this one

I'm waiting for the 100a driver which will arrive this week. Luckily, I already have spare 360° hall sensors just in case the 90° one won't work but I will not connect them yet.

After reading many threads I figured out what the issue was. This forum is a great resource.

I needed to switch the wires from motors to the ibt2's. The motion was inverted.

Good news, everything works perfectly. Nothing is burnt and the 90° hall sensors are perfect for this job.

Next step would be finishing the frame and getting simhub motion license.

Not sure if I want to wait for the 100a driver. Will use it only if ibt2's fail when I increase the voltage. But hopefully my cooling solution will keep them alive.

@Attyla.pl The 100a controller you recommended arrived. I decided to switch to it, I want to avoid issues with ibt2s in the future.

What sketch are you using for smc3? I saw a modified sketch with soft start,... Don't even know what a soft start is but it seems a desirable feature is somebody took the time to create a sketch for it

Also, what settings should I go for in smc3? I find hard to understand the settings. I want to limit the movement to 20° up and down to start with

For now I use the standard version from this atku
https://www.xsimulator.net/communit...3dof-motor-driver-and-windows-utilities.4957/

it is important to set MODE 1 in the .smc3.ino file before uploading to the arduino board .
The softstart version gave me problems .
As for soft start and limiting the size of the movement then try this program
https://www.simhubdash.com/

Every time you run the program you have free 10 minutes to use the movement , the program is very easy to use and from what my colleague told me it handles something like soft start by itself .
In SIMHUB you can easily limit the pivot ranges.
The license costs only 35USD.

@Attyla.pl I followed your instruction, everything works well!!

My problem now is that I need to manually center the motors in smc3 every time I turn on the computer. Is there any way for the motors to center themselves automatically on windows start up?

You did not write what you are doing, what programs you are running so I will write how it looks like for me.
1 I run FlyPTmover, load the configuration file and FlyPTmover connects to my arduino
2. I turn on the power for the motors
3. the motors automatically set to zero position , the seat goes up, you can start flying ( the takeoff movement is quite rapid)

The same mechanism works if I use SMC3Utils .