DIY 2DOF home build

Hi Guys,

I would like to share with you my attempt at a 2dof home build.
The design will be the usual shoulder mount using wiper motors at first and then
moving on to something a bit more industrial depending on how things go.
Control circuit will be handled by the trusty arduino mega.

Since programing is the bane of my existence I built a test rig first to see if I could get the
thing to talk with the computer and then use it in a simulator. The rig took me about 30 mins
to put together as I already had all the parts lying around.


After a bit of fuffing about, success!


Still needs much tweaking and a re alignment of the pushrods as rolling left is not as defined as rolling right, the video makes it look worse than it is as you can't see the track properly. There are points that look like it should roll left but doesn't because the track itself is on a lean in the first place, thus reducing roll.

Thank you xsim! All the resources needed have been extremely easy to find and well put together.
Cheers! Alexey.

NICE RIG are thos servos modified or are you running the rc servo sketch on the arduino

Hi Tady, the only unfortunate part of the rig is that it can't handle my weight !
No the servos are not modified and yes I am using the rc servo sketch.

More updates to come shortly!

Not as large of an update as I would have liked but its some progress anyway. I was hoping to get some of the frame done over the long weekend but i didn't end up having enough free time . I did hover make a little progress on the electronics side and put together my own H bridge.

I call it the Frankenbridge!


It is an amalgamation of two servo controllers mated to a H-bridge for more power handling. I have basically taken the outputs of the controller that would normally attach to the small motor and use them as inputs to a simple H-bridge. This thing should be good for 18 Amps once I have put some heat sinks on. The mosfets are IRF7842PBF link: http://www.irf.com/product-info/datasheets/data/irf7842pbf.pdf .


It's not quite the final design as I've still got much testing to do.

Also made a coupler for the pots and the motor shaft. The pots will be replaced with some good ones as these are still the original servo ones.


The design has worked with transistors so I'm pretty sure this should work a treat too.

Cost total = $18 ($5 per servo and $1 per mosfet)
I already had the servos so that was even better.

Cheers!

Hi guys, things have moved along! I ended up with a bit of an issue with the H-bridges when the motor is still, the H-Bridge gets full supply dumped through them as the motor itself acts as a short circuit. The fets are able to conduct because they are directly attached to supply, meaning they are susceptible to avalanche breakdown (voltage is high enough to to start conducting across source and drain without any base voltage). My supply is capable of delivering 40 amps all day which means that the 18 amp mosfets were getting over double the rated current. Being impatient and not wanting to go and buy 40 amp mosfets that would handle the abuse or re design the circuit to stop avalanche breakdown from occuring, I discovered some arduino stepper motor drivers:
http://www.ebay.com.au/itm/400749238150?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649 .
And I'm looking to pair with these motors:
http://www.ebay.co.uk/itm/12V-DC-Geared-Motor-Motor-with-60-1-ratio-Gearbox-Left-Hand-/111415229286?ru=http://search.stores.ebay.co.uk:80/search/search.dll?st=1&srchdesc=n&fp=0&sid=266253021&store=Motion-Control-Pro

I was originally going to use wiper motors but have decided that I want more from the sim (mount monitor to rig, custom pedals, quicker motion action). This has all been fueled by playing Assetto corsa for hours on end. The only sim that I played before was Gran Turismo 2&3 many moons ago and since then I have only dabbled in arcade racers like Grid 2 etc. After playing a couple of hours on practice mode I thought I'd break into multiplayer thinking that my time of 1:52 on Imola in the Z4 GT3 was something special. I was pummeled into the ground by most players. So I hit the books and videos and managed to get that down to a respectable 1:45 using the P4/5. To get any quicker I need to get better at trail braking which requires better pedal feel as it's hard to judge brake pressure with the DFGT pedals. Custom pedals it is then!

In other news I have made the cockpit section of the rig!

The workshop:


Early Access pre-alpha rig:


Update 0.1


Addiction:


I'm having panic attacks knowing that I have to move the rig out to modify it.

Work to be done:

Convince myself to move rig
Wash seat (a free seat is a free seat)
Battle spider horde underneath recliner handle
Shorten cockpit
Raise wheel mount
Make shoulder frame
Make pivot
Make new pedals
Make base for rig
Hack flight stick into H shifter, sequential shifter and clutch addon
Electronics wizardry
.......
Profit?

I've probably forgotten to add something like "get a life".

Cheers!

Decided that I should try to do more at home rather than relying on my lunchtime at work to get things done, so I've decided to finally get my ancient drill press restored. It's a bit of a drawn out process but it's getting there and in the end I'll be able to get more done at home with other projects and the like. It's mainly just surface rust but it's still takes a bit of time to get it all off.
I've pulled off a motor from a treadmill and it's speed controller so no need to change belts!




Also my 200W motors arrived from motion dynamics. Awesome turnover time! I ordered my motor controllers two weeks ago and they still haven't arrived.

Good stuff man

Darn are those motor's shiny when new.....lol

Well I have been a little bit busy of late but I can now post up a progress report. I have made up a custom pedal set and 2 gear shifters (5 speed H pattern and sequential). They are still a bit rough around the edges but if time permits I'll neaten them up.

Clutch, Brake, Accelerator. Yes the pedals are upside down, whats done is done and I'm too lazy to rectify it. The brake and accelerator will run from the DFGT pedal port and clutch will be handled by a logitech joystick axis.


I decided to use a slide potentiometer as it gives uniform movement and full voltage swing. Probably wont last as long but they are cheap to replace.



Double spring brake


Using two 12mm threaded rods, I can change the pedal separation (no bolts shown yet, just mock up). Also making a clamp system allows for changing pedal distance by sliding up and down frame rails.



Mock mount

Sequential shifter, at the end of the springs is a tab which activates a micro switch either side of it.



H pattern shifter, I liked this build as opposed to a clipped gate with a single spring attached to the leaver. This build allows for a realistic feel to shifting gears.



The gate looks like a dogs breakfast but the shifts are smooth and catch properly. I still need to bolt the micro switches in and wire it all up.


If anyone would like more info or more detailed pictures and a write-up of each pedal/shifter I can start a new thread if requested.

Slowly getting there.

Cheers.

great work there, looks real neat

@Alexey Those pedals are awesome! That is seriously impressive.
It also gives me ideas............dammit

Really nice DIY builds, that H-shifter looks great

Have you considered implementing Load Cell for brake instead of potentiometer?
They are also pretty cheap to replace but could last longer and give better input..

http://www.ebay.com/itm/4-pcs-Body-...051?pt=LH_DefaultDomain_0&hash=item43c82f45a3
http://www.ebay.com/itm/2pcs-x-50Kg...561?pt=LH_DefaultDomain_0&hash=item4191271001

really great work! Pretty cool idea the h-shifter, this design I have never seen before.

Wow! Beautiful! I'm impressed!

Great work @Alexey !!

nice work man, what tools did you used? a full metal workshop or just a few cleaver tools?
fer

nice work man, what tools did you used? a full metal workshop or just a few cleaver tools?
fer

with the precision of most of those cuts on the pedals/shifter, i would say he some Fancy tools to play with, Or access to some.



Nice setup Alexey, look forward to your next project.