Showroom First attemt at 2DOF Arduino sim

My name is Tim and I'm working on a 2DOF Arduino DC-motor simulator.
This project is a combination of 3 of my biggest interests: (sim) racing, arduino and (embedded) electronics and generally building things.

I came across SimTools a while back and started playing with the idea of making my own motion sim. After some basic research I got some motors, a controller and grabbed an Arduino and got the software running in no time.
The power supply and the motors (120W 24v) are from Simukit, the controller is a Monster Moto I had lying around. After many hours of figuring out why the motors wouldn't turn, I realized the controller cuts off at
around 16v... A computer PSU got it working and a Sabertooth is on its way.
At 12v it works, but just lacks in power.

For the frame I'm using a pipe joint system. It lets me play around with dimension and move about with all the components. It's stainless steel, so well strong enough.

I'm at the finetuning-stage now, both in hardware and in software. The motors and pivot points have moved further back since I took the picture but I can't really move on untill the Sabertooth arrives.

Oh, and never mind the cat. She seems to like the chair while it's stationary.

Update 04-09
The Monster Moto has been replaced by the 24v capable Sabertooth 2x32 and after some pixie wrangling its working again. I might move from the Arduino Uno to a Mega if the soft serial turns out to be an issue. I noticed some glitches during testing, but everything is lying about on my desk, so the serial wire from Arduino to Sabertooth isn't the most solid connection.
With the final components all here I can go ahead and print a nice case for it all and fix all the wires properly in place.
Next update: moving pictures! Hopefully later this evening.



Update 09-09
Small update: the pivot point has been changed from a ball-joint to a u-joint. With the ball joint the upper frame rotated uncontrollably. Moving the motors further inside did fix that, but it put the unibolts on the upper frame under stress.
With the new pivot point and the motors back in the right place it works pretty well.
The u-joint I used is an old one from a quad bike. It has some play in it, but it's only noticeable when getting on or off the sim. Fine for now.

This project is a great excuse to get me a broaching kit by the way
I've made the levers from 8mm steel plate with a keyed hole that snugly fits the motor shaft, but a hand filed keyway isn't really cutting it. Probably my filing skills and patience are to blame for that. Nonetheless, it means there's some play and as goes for anything that moves: some play will eventually turn into too much play. I've slotted the lever, put a bolt through it and tightened it on the shaft, but after a while the play was back.
So now the plan is to take some round stock of steel, make some beautiful chips on the lathe and punch a keyway in it with this broaching kit. Then weld the lever to this hub.

I'll take some pictures tomorrow.

Yeah, we'll see if it works. With some luck the Sabertooth will arrive tomorrow, so I can do a proper test.

Here's a photo of the current placement. The motors are moved back some 10 cm and the linkages are a bit longer. Also, the motors moved inwards a bit to limit the rotation. I'm using a ball joint from a car's steering rack so it tends to rotate. Maybe I'll have to replace it, but it's pretty much gone with the current lay-out.

So the Sabertooth 2x32 arrived in the mail this morning.
I downloaded the Arduino sketch from here: https://www.xsimulator.net/communit...bertooth-using-simplified-serial-working.136/
and used the interface settings as provided in the topic. I did change the interface output from <Axis1> and <Axis2> to <Axis1a> and <Axis2a> to work with SimTools 2.1
Set the dip switches, wired it up and gave it some pixiejuice.

I ran into some problems, but I figured it out. Best to read entire threads on stuff like this, not just the first post

After setting up the Sabertooth with DEScribe and getting the DIP switches right it worked
Aparently there's an updated version of the board with all different settings 'n stuff. Good stuff, but it's not backwards compatible.

This is the thread with all the answers: https://www.xsimulator.net/community/threads/smc3-sabretooth-test-version.6236/

Right, time to bolt it all back into the frame and continue testing

I'll leave original post for archiving sake. Maybe someone sometime will run into the same issue.

First thing I noticed was that only motor 1 is moving. I changed the motors around but it's still only channel 1 on the Sabertooth is outputting anything.

The moving motor is behaving strange though. It's jittering about, even after setting the deadzone to 6 on both axis. For testing purpose I've only enabled roll on both axis.
It seems to ignore the pot value, as it just keeps on going round. Luckily my testing setup allows for the gear on the pot to spin freely after hitting the end stop of the pot so no damage was done, but I can't figure out why it's behaving like it is.

I've also tried the SMC3 version with Sabertooth support, but while using SMC3Utils the motor starts to move with all values set to 0. It moves the green pot-line past the target line and only stops when it passes the limits.
The maker of the SMC3 tools did note it was an unconfirmed test, so I went back to the sketch by Wanegain, but now I'm all out of idea's.

Is there someone here with a setup like mine and has an idea as to what I'm doing wrong?

It's alive!



More hardware fine tuning tomorrow, like the motor mount angle and main pivot point.

Small update: the pivot point has been changed from a ball-joint to a u-joint. With the ball joint the upper frame rotated uncontrollably. Moving the motors further inside did fix that, but it put the unibolts on the upper frame under stress.
With the new pivot point and the motors back in the right place it works pretty well.
The u-joint I used is an old one from a quad bike. It has some play in it, but it's only noticeable when getting on or off the sim. Fine for now.

This project is a great excuse to get me a broaching kit by the way
I've made the levers from 8mm steel plate with a keyed hole that snugly fits the motor shaft, but a hand filed keyway isn't really cutting it. Probably my filing skills and patience are to blame for that. Nonetheless, it means there's some play and as goes for anything that moves: some play will eventually turn into too much play. I've slotted the lever, put a bolt through it and tightened it on the shaft, but after a while the play was back.
So now the plan is to take some round stock of steel, make some beautiful chips on the lathe and punch a keyway in it with this broaching kit. Then weld the lever to this hub.

I'll take some pictures tomorrow.