Hi, Need some advice for my build

[adamharro]

Hi my name is Adam and I'm from Australia, I'm an instrument technician by trade and am very interested in building my own rig. I have done research and think i would like to go with a boat winch or worm drive motor as the SCN5 actuator seems very jerky and expensive in comparison. I would love to be able to do this for less than 600$

I have been doing some sketches with my friend who is good at welding and fabricating with metal and we have come up with the following design, We plan on using some telescopic tubing from gym equipment to allow it to be adjustable for the pedals. Its not done to scale.



We are planning to use the following

Square steel tubing
Bucket Seat
Boat Winch/Worm Drive This or This ... Not sure but would love to here some input
2 x Potentiometers
2 x Jrk12v12
1 x Uni joint ball
2 x sway bar linkage

I have a few questions -

1. When connecting the potentiometers what stops the motor spinning around and snapping the arm other then the controller output? Do you set a limit on how far it can go around? For example 0v = 20% and 12v = 80%. Can i mount it directly flush with the shaft so there is no lever arm?

2. Does there need to be a battery involved to keep power on the motors and controller when not using it? Will it lose its program?

3. Can i use a 600w CPU power supply if its rated 40amps@12v?

4. With our design, Is it better to have longer rods connecting to the top of the chair or the base, Is leverage something that can be problematic?

4. Do i need springs anywhere or stops to help save the motors life?

If you can think of anything wrong or something that just wont work please let me know, any help is much appreciated as i would love to have this done before Christmas!

[motiondave]

Ok Adam, welcome and good luck.
First thing to ask, how much do you weigh and height.

Motors, http://www.motiondynamics.com.au/worm-d ... orque.html they will work under the back ish of the seat, I have done this before.
If you can consider moving them forward to your knees or a bit further, it helps with weight shifting.
Boat winches will moves more weight, but they are noisy.

Control boards, http://www.pololu.com/catalog/product/1393 one per motor, easy to wire and they run 30 amps continuous at 14v with heatsink on the big chip and cooling.

Mounting pots, various ways, Bobuilt is using them in the back of the motor shaft, single turn.
I use either cut out plastic levers or gears depending on set up.
With JRKS, they have feedback disconnect so there is NO chance the motors will over spin.
JRKS are firmware based that remember after they are switched off, so no need to re-program.
For power supply, you will need something grunty.
A cheap option is a car battery in parallel with a 20 amp psu.
If you go psu's straightway, allow 40 amps per motor.
Leverage is always good. if you can extend the frame at the back and have motors connecting to shoulders, this is the good option, mind you, motors underneath work just as well. I have been through 9 designs testing ideas. All work.
No need for springs, they were only on my wiper motors and wipers are soft gearing and it stopped them thrashing out. NO CHANCE of that with motion dynamics and or winches motors.
Yes it could be done before xmas.
We will endeavor to assist you to do so
Cheers, David.

[adamharro]

Thanks for the response.

I'm 100kg at 6 foot 4 so i will most likely be the heaviest person on it.

I will note all this down. I underestimated the power significantly.

I also read about grounding issues with the motor but i cannot find that thread again or the diagram. Do you guys just power it up & meter its casing before plugging it in to the controller? Might buy a USB isolator because i can see my motherboard possibly getting pumped.

What sort of heat sink do you recommend using? I'm thinking of a standard CPU heat sink but it would have to be modified to latch on properly, is there something already out there suitable? I'm thinking of putting the controllers into a plastic box with a cover and 2 computer fans, is this something similar you guys do?

[adamharro]

Sweet, That was the diagram i was looking for.

I'm on the east coast, Newcastle.

I can imagine you would, i sit and play a V8SC mod for rfactor for hours without any motion!

Do you guys notice the power bill go up with these long sessions and high amp power supplies?

[adamharro]

Yea that's great if you could send me some cad drawings, Ill PM you my email address.

Good too see there is a community in Australia growing for this i didn't even expect anyone to be doing this in Aus. Ive seen the simworx/CKAS stuff on there websites as well, have you guys ever used them?

I would be happy to join your guys group as well.

[motiondave]

I am part of the league in progress.....we try to play on weekends causally between 7pm -9pm currently between me and Bob, that should move to after 10pm EST in a few weeks, I just need to get setup to play late at night.
not sure about power bill, lets see, pc 800 watts, 24 " monitor 90 watts, 17" monitor 50 watts, wheel and pedals, dunno 12v 2 amp power pack. Power supply to run motors, doesnt say input, but puts out 30 amps at 14v, going to car battery, maybe 1kw per hour? oh what the heck!
Lets race .
I have never used simworxs ckas, only played a bit on sim place in Darling Harbour, and they have dbox setups. Not bad, big motors better....sorry dbox.
We will have you moving in no time.