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Showroom DIY Budget Compact Build

Discussion in 'DIY Motion Simulator Projects' started by bixler13, Mar 6, 2019.

  1. bixler13

    bixler13 New Member

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    Hello all, I am currently working on a 2 dof budget full frame build. I am building this chair mainly for use in flight sims such as X-plane and DCS, but will also be using it for racing games. Because I intend to mostly use it for flight sims, I decided to go with a full frame setup rather than the seat mover.

    I also will have to move this simulator across the country in a couple of months therefore I want to be able to easily disassemble it for transportation. Because of this, I intend on constructing much of it out of slotted steel and aluminum plates with no welding.

    My design was inspired by @noorbeast compact simulator. I really like how small the footprint was on his sim as well as the different configurations he is able to use with the flight stick and steering wheel. The following images show what I have currently drawn up. The main construction is 1.5inch slotted steel tubing and slotted angle as I can get it local at Home Depot for pretty cheap. I know steel is very heavy so I plan on trying to use aluminum for the rudder pedal assembly in order to reduce the moment of inertia of the frame.

    1.JPG
    2.JPG
    back.png left.png

    I want to use 2 inch aluminum tubing for the rudder pedal assembly like @noorbest did on his but I cant find any for locally and don’t want to pay huge shipping costs. I can only find 1 inch aluminum tubing so that’s what I have modeled now although I seriously doubt it will hold up. I am welcome to input and ideas.

    I also have access to a water jet cutter at my university and have a large 6mm aluminum plate that I plan on using for the seat base as well as brackets on the pedal assembly and motor mount plates.

    The following image shows the input in SimCalc. Numbers to me seem pretty reasonable, but would like people’s opinions. I have read that flight sims chairs typically should achieve further angles at the cost of the chairs acceleration so I might lengthen the CTC lever a tad more to get in the 15-degree range.

    simcalc.JPG

    Parts (purchased):

    Motors ($255 shipped) - pgsaw 50:1 12v gear motors. 50:1 as this will be a compact build therefore will need the high torque from the 50:1. CTC lever of about 2in.

    Seat ($53 shipped) - Jegs Pro Highback Seat. This seat weighs only 13lbs and should be pretty easy to mount to the frame. It will mount directly on top of the aluminum plate I will be water cutting.

    Power Supply ($55) – HP 12v 1200W. I have seen most people go with a power supply for each motor however I might try just using this one at first to reduce costs. If I run into issues, I will be purchasing another.

    Universal Joint ($64 )- 2x Flange Yoke + U – Joint. This seems like a pretty standard way of going about the u-joint so I don’t foresee having issues here.


    Parts (not purchased):

    Motor Controller: I really want to go with a sabertooth 2x32 I am still going to do some reading about the motomonster clones to see if I think I could get away with one. Either way I will be using it with an Arduino rather than going with the JRK because of its cost.

    Pots: I will likely go with hall effect sensors based on people’s recommendations. I will be buying the 987-1392-ND hall effect sensors.

    More to come. Please let me know if you have any feedback or recommendations!
    Last edited: Mar 14, 2019
  2. noorbeast

    noorbeast VR - The Next Generation Staff Member Moderator

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    My Motion Simulator:
    3DOF, DC motor, JRK
    The brace bar I used between the two motors greatly adds to structural integrity and stiffness.

    MM clones are known to be dodgy, the Sabertooth is pretty much bullet proof.

    In a compact design the experience of the speed it amplified by the height of the seat back.

    I suspect 1" will flex too much, even with bracing.
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  3. bixler13

    bixler13 New Member

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    Great thanks for the advice. Ill definitely look into the brace bar!

    I actually had a question about your build actually @noorbeast. Why did you decide to raise the rod mount connection with the alternator brackets? In the following picture you mounted to the blue circle whereas I am planning on attaching directly to the seat frame (red circle in below pic). I tried running the numbers through SimCalc and it didn't seem to have any benefit in raising the rod mount connection above the u-joint by a couple inches. Thanks!
    question.JPG
    Last edited: Mar 14, 2019
  4. noorbeast

    noorbeast VR - The Next Generation Staff Member Moderator

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    My Motion Simulator:
    3DOF, DC motor, JRK
    I was trying to get the maximum design leverage relative to the pivot while keeping it pretty compact.
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  5. bixler13

    bixler13 New Member

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    Current progress.

    I received the poly chair from jegs. It turns out it is surprisingly conformable without a cover and will work perfect for this project.

    I bit the bullet and ordered a sabertooth 2x32 ($125). I did not receive any voltage clamp resistors in the package as I have seen others have, so I will be working out which resistors I need to buy next. If anybody has any recommendations that would be great.

    I also purchased the slotted steel tubing. The hardware store ran out of 1.5 inch steel tubing so I will be mostly using 1 inch steel tubing. It feels pretty strong anyway so I don't think it will be an issue. Also drew out of the final iteration of the plate I will be water cutting out of a sheet of aluminum for the seat base. I am hoping to get this cut by the end of the week. I put lots of holes lengthwise so I can move the universal joint and seat around to get the ideal balance.

    Attached Files:

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  6. CBC_North

    CBC_North Member Gold Contributor

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    My Motion Simulator:
    2DOF, DC motor, Arduino
    My build is very similar to yours. It's using the same 50:1 motors, same controller, same pots and was also based off @noorbeast 's design so hopefully this advice is useful.
    • Good choice on getting the sabertooth. I originally started with Monster motos and went through a few days of frustration until finally upgrading to the sabertooth. It's been relatively smooth since.
    • I used two 50W 6 Ohm resistors for each connection in parallel. The ones with an integrated heatsink often used for car turn signals. Two in parallel gave me an effective 100W 3 Ohm for each motor. This should be ok but if you can actually calculate the current pull of the motor, the manufacturer has a resistor calculator on their website.
    • Even with the clamping resistors I was still tripping the current protection on my server power supplies (2 x 750 W in parallel). I had to add a massive bridge rectifier (but wired so it was effectively a giant diode) inline with the +12v from my supplies to keep them from tripping. See here for using a rectifier as a diode: https://www.xsimulator.net/community/faq/protecting-psus.255/
    • I second Noorbeast's suggestion of adding a stabilizing bar between the two motors. Dramatically increased the rigidity of my motor mounting.
    • I connected the linkages directly to the bottom of the platform on which my chair was bolted like you have planned. I found that I had more than enough leverage with the 50:1 motors. I weigh about 185 lbs. and my mitsubishi eclipse chair was about another 40. Getting the seat platform properly balanced over the u-joint when loaded with a person helps a lot with this. I kept the sliders for my chairs so I could dial it in after mounting. This will be very important for you with the foot pedal extension coming off the front of the platform.
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  7. bixler13

    bixler13 New Member

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    Awesome thank you for the info!

    I just purchased eight of those 50w 6 Ohm resistors and plan on running 2 sets (one for each motor) of 4 in parallel to get a giant 1.5 ohm resistor which is what the sabertooth calculator recommends in order to get the maximum of 8 amps through the voltage clamp resistors.

    Also I purchased a couple bridge rectifier's and plan on running one for each power supply as diodes. I originally planed on running one 1200w server power supply for the whole rig but it seems most people are running a power supply for each motor so I went ahead and bought a second. I now will have two different model HP server power supplies but with the same specs so i'm hoping I don't run into issues when paralleling them into the sabertooth.

    What did you use for the stabilizing bar between the two motors?

    Also I read through your build thread and you said you found a CAD model of the pgsaw motors. Do you have a link for that? It would be of great help.

    Thanks again!
  8. noorbeast

    noorbeast VR - The Next Generation Staff Member Moderator

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    My Motion Simulator:
    3DOF, DC motor, JRK
    3D model of pgsaw motors can be found here: https://www.xsimulator.net/community/faq/3d-model-of-pgsw-motion-dynamic-motors.247/

    I used solid aluminum round bar, tapped either end, to act as a brace between the motors, using the top gearbox hole.:

    [​IMG]
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  9. CBC_North

    CBC_North Member Gold Contributor

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    My Motion Simulator:
    2DOF, DC motor, Arduino
    I made my bracing bar in the same way as Noorbeast. A piece of solid aluminum round stock cut to length and threaded on both ends.

    As for the pgsaw 3d model, the overall size is good for checking clearances but the mounting holes are NOT spaced correctly in the model. I designed my pot mounts using the dimensions on the pg saw model to be 3d printed and they were off by a fair bit. I had to manually measure the distances and re-print my mounts.
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  10. bixler13

    bixler13 New Member

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    Great thanks i'll wait for mine to come in then and get the measurements. Also is there a thread somewhere that explains how to switch the gearbox around so I can mount the motors with the cans facing the same direction? Or maybe it will be common sense when the motors come in.

    Also was wondering if you have to earth isolate your motors? I know some wipers need to be earth isolated but I haven't read anywhere about the pgsaw motors. Thanks again for all the help!
  11. CBC_North

    CBC_North Member Gold Contributor

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    My Motion Simulator:
    2DOF, DC motor, Arduino
    There's definitely a thread that explains how to change the gear boxes somewhere but it's been a while since I saw it. I personally did not bother. They're only slightly different on each side. I just designed the through shafts to account for this. One side has the shaft pinned to the outside of the mother while the other has the shaft pinned on the inner side. It seemed like a lot of work for something I could easily compensate for.

    You do not need to earth isolate the pgsaw motors. Only connections are to the + and - motor outputs on the sabertooth.
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  12. bixler13

    bixler13 New Member

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    I got more work done today on the sim.

    I began with the universal joint. In its stock configuration it only allowed for 12 degrees in each axis. I want to be in the 20 degree range so I took it too the mill and now have 23 degrees in each axis. (23 roll right, 23 roll left).
    53708089_359303881336152_8251023790734049280_n.jpg 53618361_392836671549932_8571248460605423616_n.jpg 53892538_338249497034068_175667989222260736_n.jpg 54517960_798409107180397_1333140436880982016_n.jpg

    I than moved onto working on the 6x6 inch steel tube that I am using as the riser for the joint. I cut it down to 21 inches and drilled holes for the slotted tubing in the mill.
    53289690_1053543228171886_4559216391542013952_n.jpg 54517054_444368662974313_5843651809092042752_n.jpg

    I then needed 90 degree angle brackets for the slotted tubing in the base. I found some scrap aluminum angle and cut it down to the size of the slotted tubing. Cut holes that lined up with the slotted tubing and I had a pretty sturdy base. The base is 35x24 inches right now but might be changed down the road.

    53400529_1655619857872314_3115407867352449024_n.jpg 53968564_2196949993954697_4258842652490858496_n.jpg 53752234_419079602186766_3954934769535418368_n.jpg 53792616_375841069905083_7132559000561778688_n.jpg

    Finally, I needed a way to mount the u-joint flange onto the top of the 6x6 tube. I found some pretty thick steel stock, cut it to size and drilled holes for the u-joint flange. I plan on welding this steel plate to the top of the 6x6 steel riser.
    53761916_2518324708241962_439322704240181248_n.jpg 53179964_803887343281698_4212853362456002560_n.jpg

    All of this leaves me with what I have pictured below. The motors are arriving this weekend and the aluminum seat plate is getting water jet cut by the end of this week. I am looking forward to making motor mounts and getting the seat mounted.

    53588509_707980959599628_7259304335870263296_n.jpg 53806346_388146321765559_7231510103554260992_n.jpg
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  13. bixler13

    bixler13 New Member

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    Here is my most recent progress on the sim chair.

    I first put the motors in the mill and drilled out the mounting holes for use with SAE hardware. Very easy to as the gear box is aluminum.

    54515852_264446511110784_3436692612461887488_n.jpg 54254934_993540081034074_2397116016350986240_n.jpg

    Next I put a pretty thick piece of steel in the mill and tried my best to get it to fit around the gearbox to act as a motor mount. It actually came out pretty good and appears to be very strong.

    54515106_2286735801579370_41925623907614720_n.jpg 54142948_298368567498074_8693406332755116032_n.jpg 54114932_2122123234532710_1281922273271349248_n.jpg

    Next I worked on the bar connecting the two top holes in the gearboxes of the motors as multiple members have recommended for extra motor rigidity. I began with a .75in solid stainless steel bar. I used a lathe to chamfer the edges and then drill and tap the ends. I then followed up back in the mill to create two flats for a wrench to grab the bar to tighten it.

    54408464_410160756196275_958089409964539904_n.jpg 54436148_550248075483651_6282751196507668480_n.jpg 54516996_421973775221609_5204797156346560512_n.jpg 54525143_636556600107612_6091065659330920448_n.jpg

    I also welded the plate for the u joint on the 6x6 steel tube riser. For my first time welding it didn't come out too bad.

    54517188_2064187360549082_2654022036371800064_n.jpg

    I custom made levers out of steel. I used a bolt that fits into the shaft of the pgsaw motor welded to the lever. I have seen other people on this forum use this method so I don't foresee it causing me issues. I might make a backup set of levers at different lengths and with thicker steel just in case these aren't strong enough.

    54353527_258160841796294_6566792197134352384_n.jpg 54407606_2377737139125186_3399468487389741056_n.jpg 54728592_522266731635209_5217298646504046592_n.jpg 53833956_2839563076055662_1750771666490753024_n.jpg 54437386_257379631869893_8454839926167437312_n.jpg
    54433315_388150708683674_5371740769910521856_n.jpg

    The seat plate was watercut out of aluminum and came out pretty good. It feel very strong and all the holes line up great with the u-joint and seat. I am using aluminum spacers that were cut from an aluminum tube to allow for room for the u joint bolts.

    54435850_2299446013409808_1862810827619303424_n (1).jpg 54433341_524932264581710_1310561321359507456_n.jpg


    Since this will be a full frame sim the rudder pedal assembly will be attached to the seat plate and therefore move with the seat. I am using 1.75 inch aluminum square tubing for the assembly. This was my first attempt at brackets. I used very thin sheet of aluminum for the first brackets and they actually came out surprisingly strong.

    54414038_2131498803609087_2423898397321723904_n.jpg 54255632_606773279802860_2307853135512600576_n.jpg

    I decided to remake them out of stainless steel as I had a large sheet that could accommodate both joints in one plate.

    54432401_632705937175803_8838108213363605504_n.jpg 54420982_513920645801181_4773297958374342656_n.jpg 55443464_396097397635736_6999884441426329600_n.jpg 54268402_352927902097992_8726270095359213568_n.jpg 54257963_567151463780327_1111393998397767680_n.jpg
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  14. bixler13

    bixler13 New Member

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    I am using two (1) (2) 1200w 12v HP server power supplies in parallel to create a giant 2400w 12v supply. It will really be max 1800w since i'm only using 120v input and the power supplies can only put out the full 1200w on 240v.

    In order to turn these supplies on, I wired up a resistor between pin 33 and 36. I used a 330 ohm resistor. I initially thought I could just plug them both in and wire them in parallel but after a bit of research I found this was not the case. I found that simply wiring the supplies in parallel will put all the load on the supply putting out the higher voltage rather than spread it evenly. Luckily these server power supplies have a load sharing option that enables you to connect up to 4 power supplies to evenly spread the load among them. I found this information between this rc groups thread and this post. They say that connecting pin 34 of the supplies will enable the integrated load share circuitry.


    Additionally, in this post, AD0AR claimed to run two HP supplies in parallel with the load share pins connected and got a constant 140a at 13.4v. Pretty impressive. Even more impressive would be connecting 4 in parallel, and with a grand cost of $120 you could have a 280a 12v power supply. Good luck beating that for the price.

    The below pics show it all wired up. I haven’t done any testing with loads yet, but they both seemed to start up and run good.

    54436306_297227974290277_5693177269099429888_n.jpg 55526883_2258860521029563_9220284071333068800_n.jpg 54430448_847515932264358_6364327705088884736_n.jpg
  15. bixler13

    bixler13 New Member

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    Well the stainless steel plates just didn't do it for me. I tried cutting the holes in the mill and just couldn't get them straight enough, so I decided to water jet cut some plates out of 1/4 in aluminum. Will at it, I also cut the foot plate in addition to the two plates that will hold the stick and throttle.

    54516336_2223949027698009_1782666432933265408_n.jpg 55551860_2546514472045102_7779014637319618560_n.jpg

    These ones fit perfect, and will be much easier to work with down the road when I need to cut new holes for mounting peripherals as they are aluminum and not steel.

    54515124_1161762490667626_9046504828338962432_n.jpg 54256111_271973773738623_8108430889391751168_n.jpg 54415995_839249579745009_156809556624670720_n.jpg

    I mounted two lengths of 1 in tubing on the end of the footplate in place of the rudder pedals I still need to make/order. The plate is adjustable and can move forward and back depending on how the user feels comfortable. In these pictures I have it mounted in the closest position.

    54771027_829543740714244_4338012416018219008_n.jpg 54727360_329791674337641_8233250636242616320_n.jpg 55593304_405999596882653_1430776785959649280_n.jpg

    Next, I cut some 90 degree adapters out of a piece of aluminum angle. These mount to the side of the chair platform and allow for the stick and throttle plates to be raised up a bit.

    55769909_397648541034328_414781024887635968_n.jpg 54462800_787236128329188_7848670897962483712_n.jpg 54435594_298554520817025_6862972901348343808_n.jpg 55503374_600244210447179_9147825327349694464_n.jpg

    Finally, I put all the aluminum plates in the metal planer to get a good finish. They came out looking great.

    55470334_632104813908088_2742461340051308544_n.jpg 54420935_2287245541499482_2153960879589163008_n.jpg 54434665_378641786304770_5035000550626689024_n.jpg

    Also, I made new lever arms for the motor as the other ones I made were probably two thin and would flex while in use.

    55453678_2340622709549198_5570644699707867136_n.jpg 55726312_312836166045445_2896147282925715456_n.jpg

    Next step is final assembly and pot mounting.

    Attached Files:

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