Help! 2DOF Build Power box

I've been wanting to build or buy a motion sim for quite a few years now, and this winter, it has been an ongoing itch. Given that some of the cheapest motion sims range from $1,500 to $3,000, not including the $500 shipping, I've decided to build one. I plan to use 4040 aluminum extrusion and PG Saw 50:1 motors found on eBay. I've read that these motors can reach around 30 amps before stalling. I'm no electrician and don't have much of a clue when it comes to amps, watts, or what size wire to use. However, I’ve been following DMax on YouTube for the last few weeks, and he has been extremely informative when it comes to wiring. Most of his setups use 12V car batteries, but I want to build a power box that I can plug into my 110V wall outlet, similar to DOF Reality. I was going to use (2) 50 amp, 600W power supplies and fuse the IBT-2 controllers down to 30 amps. From what I understand, 12-gauge AWG wire would be the safest to run for both the AC and DC sides.

My questions are:

1. Will this simple wiring diagram work?
2. Do I actually need to run 12-gauge wire (it seems a little too thick)?
3. Should I run 12-gauge wire or thicker from the motors to the motor controller, if I want to place my power box no more than 6 feet away from my motors (2DOF)?
4. Would you recommend anything different?
5. Do i need a fuse on the fans? (I would assume no because they are rated to handle max speed and will only draw what is needed from power supply.)
6. Should the fuse go before the ibt-2 (like in the diagram) or after the ibt-2.... dose it matter?

I wouldn’t worry too much about the wire thickness. The duty cycle for 30 amps is almost nothing. I have only ever had heat when I screwed up.

I have my fuses before the ibt2. There is no downside to this as far as I know.

Also I have my stop button on the DC power side. The AC will have considerable lag. You can do a test where you just unplug it and see how long it takes for the motors to stop. I may be just OCD on this after working 30 years on factory equipment.

I personally use a “master control relay” for the DC main power. The relay is really cheap like $12 at Amazon. I literally use telephone cord for the estop panel. I have a light there so I can tell when power is on.

This is handy when working on the rig as you really don’t want your fingers on the works with power on. I have a second handheld panel I plug into the relay when I am working on the rig.

Hey, thanks for the info! I'll definitely use a master control relay for the DC main power as an emergency stop solution. I know you mentioned not to worry too much about wire thickness, but I was under the impression that the thickness of the wire determines how much current it can handle. Like I said, I don't know much about this and I'm eager to learn. From what I’ve researched and according to my plan, if my motors peak at 30 amps, I would technically need to run 10 AWG wire from the DC side. As for the master control relay, would I go from both power supplies to one relay, then split the output to each 30A fuse? In that case, I'm assuming I’d need a 60A relay?

PS.. Love the pup what is their name? Made me decide what to to what my profile pic as well.

It’s all about heat. So if you are running a 30Amp motor 100% of the time that’s a problem. 1% of the time no issue. Since I run 24v that does reduce the current. Your wires will never be too think but I don’t think you can squeeze a 12 gauge wire under the screw on the ibt-2.

I have a 24v 120 amp mechanical relay that cost $12. I have never had a noise issue that crashed the Arduino in this context. If you are concerned you can get solid state relays for about the same price. Dont forget the resister for solid state.

I think if you have two power supplies you would want two relays. You can control both with the same estop. I have a single 1200W power supply. That’s 10 amps from the 120v AC which is about the limit for a 15 amp breaker.

That’s Niki at about a year old. She was a beaut.

Okay, I think I get it now. I didn’t realize that copper wire can handle more amps than aluminum wire until I found this chart. Based on the type of copper wire, I can use a smaller gauge for higher amps because copper can withstand higher temperatures. I had assumed that the wire gauge had to be bigger to handle higher amps, so I was planning to use aluminum wire.

So, you're suggesting that I can use 14g AWG THWN-2/THHN wire because it can support 25 amps, and the system typically won’t draw more than 25 amps continuously. If it does, the 30-amp fuse will blow. And unless the system is running above 25 amps continuously, the wires shouldn’t burn up. But in theory, if it were to run at 25.5 or 26 amps continuously, the wire could burn out before the fuse blows. However, it is unlikely because it will never stay at 25+ amps unless the motors are stalling out.

Sounds good.

At the limit the insulation on the wire will melt and things will short out. It’s a good test in general to check if things are getting warm. I started out with an underpowered motor and they got hot. Now not a bit. The ibt-2 will get a bit warm but not with a fan moving the air.

I have connectors on my motors. Screwing the wires in every time gets old quickly.

Just finished up wiring this is what I got built up. i worried about how hot things were gonna get so I did decide to use mostly 12g wire for areas I can. Just a little extra precaution. I’m no expert and it’s not perfect by any means but pretty happy with it I also got 2 140mm fans on the top panel blowing on each ibt-2’s

Looks professional !

Okay, so I just got everything working, but I ran into some problems.

Problem #1
I didn’t like the connections going into the IBT-2 with 12-gauge wire. Some of them stuck out a little, and I wanted to reduce the risk of them touching the metal case. So, I decided to switch to 14-gauge wire with a high-temp coating, which made things a bit cleaner. Because of this, I also reduced the fuse to 25 amps.

Problem #2
I have no clue whether it was me soldering too close, causing a bit of solder to fling onto the Arduino, or if something was faulty from the manufacturer. However, I had a strange issue where the ground on the 8-pin connector side of one IBT-2 started smoking. I checked all the connections, and everything was correct.

After replacing the wire and trying again, I found that the smoke was actually coming from the Arduino. I noticed a small bubble on a chip next to the USB inlet. I replaced both the Arduino and the cookie adapter (since it had melted slightly), and after that, everything worked as it should!


Next Steps
Next up is a monitor mount and a shifter mount. I have something in mind for the shifter and will update if it works.

However, I’m having a hard time designing a fixed monitor bracket that won’t move due to the force of the rig. I don’t have a 3D printer or know anyone with one, so this has been a challenge without one.

The thing next to the usb connector is the voltage regulator. I have gotten those very hot but only recently burned down an Arduino.

A year ago I had a sensor that kept shorting out to the point where that chip and the 20 gauge sensor wire got really hot. I am still using that genuine Arduino on my rig.

One tip is to always verify that you get the usb connected sound from the PC when connecting. This won’t happen if there is a short somewhere.

By the way, which chair are you using?

In my posts I was using a no name cheap seat. It was getting old (2017) and deteriorating.

Recently I bought one from Trak Racer. I wouldn’t recommend it because it’s not square but it’s pretty solid and fits me well. If you decide to buy one make sure the shoulder and hip interior measurements fit you. If you can’t find measurements then maybe you don’t want the seat.

Thanks a lot Joe, i'll keep that in mind.

sorry for the delay been heavily tweaking and adjusting the rig the last couple days the chair i got is from amazon. https://a.co/d/4lGoWQx I will say when installing it make sure the brackets are square otherwise it will latch in the wrong position on the other.

Seems like it’s the same seat. Mine did last 8 years and when I took it completely off there were a lot of loose bolts. The slides are bolted to the frame and those bolts were quite loose. The new seat a bought was not that big of an improvement…

Upon testing, I noticed a lot of noise coming from the motors while in a standstill position. I found that the cheap potentiometers were experiencing interference from the motors' power draw. Initially, I had the potentiometer wire and the motor power wire taped together for cable management, but removing this significantly reduced the interference. However, the motors were still noisy.

My next solution, which worked extremely well, was soldering a 0.1µF (100nF) capacitor to the ground and wiper of the pots. This drastically reduced the noise in the motors. For anyone using potentiometers and experiencing noise when the system is powered on, I highly recommend using these: https://a.co/d/9alsiEb. To my knowledge, this is a better solution than increasing the dead zone in SMC3 because doing so would cause you to lose lower input signals from the game that fall within that dead zone.

Another adjustment I made was to the rod length. Initially, I set up my lever arms to be horizontal to the rig when in a neutral position. However, this setup caused the rig to overextend, literally throwing me off the machine and leading to catastrophic failures. To fix this, I angled the lever arms 25 degrees downward in the neutral position by extending the rods. This solved the overextension issue, made the rig feel much more stable, and prevented the footplate from hitting the ground when in the resting position.

Lastly, I realized that I had wired my potentiometer incorrectly on the second motor. I was experiencing an issue where the rig wouldn’t power back on unless I lifted it manually. This was because the potentiometer was incorrectly reading the upward position instead of the downward position, causing it to exceed the max limits in SMC3. Flipping the ground and VCC, as well as reversing the motor’s + and - connections, fixed the issue. Now, the rig powers on every time, and the potentiometers both read correctly.
Got to pat my self on the back today!

I couldn’t have done it without the help of others on this forum. This is a great community, and I’m happy to help as much as I can. I’ve thought about recording the process or at least giving an overview of the build, and links to the parts however, I’m not very camera worthy lol.

Here’s the current state, still fine tuning the settings and making adjustments here and there. Overall, the build took about 4 weekends, including two for the power box and rewiring it.

I used the Hotas mounts for my Logitech shifter and flight controls there’s a little flex but I don’t mind it too much