DIY 2DOF home build

Fine work. Can you tell me where you get those slide pots?

Impressive work! The craftsmanship is nothing less than superb. Well done!

Actually you have given me an idea to make an mk2 set of pedals:

Clutch: using master and slave from a real clutch, have a strain gauge on the slaves pin outputting clutch force.
Brake: Using slave from real car brake system have a caliper piston pressing on strain guage for force output.
Accelerator: Using a real throttle body from engine intake with potentiometer attached to butterfly shaft.

In response to tools used here is the list:

Digital calipers
Vice clamp
G-clamps
Set square
Adjustable square
Centre punch
Cordless drill
Drill Press
Hacksaw
Hand file
Cold saw (slower moving metal cutoff saw)
Nibbler
Drill Set
Tap set M3 to M12
Die set M3 to M12

The only two specialized tools are the cold saw and the nibbler. The cold saw gives a very precise cut and it cuts aluminum without clogging the blade as a cutoff saw would. The cold saw was only used to cut the aluminum angle and tube to length. The nibbler is a hand operated guillotine which I used to cut the aluminum sheet. The drill press and calipers were my most used tools. Every other cut was done with a hacksaw and hand file.

For instance if you look at the pedals and where the lever is mounted, that slot which lets the pedal travel through the tube section was first drilled with a 13mm drill at the end position. I then used the calipers to scribe out parallel lines from the front of the tube to the 13mm hole. I then used a hacksaw to cut along those lines giving me the slot which lets the pedal move backwards and forwards. Then I used a file to finish off the cut. The trick is to cut less material out with the hacksaw which keeps the scribed line still visible after the cut but also gives room for error. Then with the hand file you can very accurately file away the rest of the material down to the scribed line.

Another example: You can see the three pedals all slide along the two threaded rods. If there is more than a few mm play they would catch and jam up and be really hard to adjust side to side. To keep the holes in exactly the same place from pedal to pedal is really easy to do.
Firstly you scribe out measurements with calipers. For the height of the hole lets just say you scribe out a line 10mm down from the top side of the tube. You set 10mm on the calipers and lock the position with the locking screw, then using the calipers sharp ended jaws you keep the top jaw sitting on top of the tube and slide the caliper along marking out a line with the bottom of the jaw scribing the line. Repeat for all three pedals.
Then to mark the spacing of the two holes you just set the first holes distance by measuring a distance from the side of the tube and marking it by using the calipers jaws, lets say 80mm. Mark all of the pedals at the same time without changing the calipers so that you don't get compounding errors. Then mark the second hole the same way, lets just say measure out 140mm with the calipers and mark the tube. Using a center punch at the marks will give you accurate hole positions by stopping the drill from wandering during drilling. If you have a drill press you only have to mark one side of the tube as you can just clamp your tube to the drill table and drill all the way though. If you don't have a drill press you can still do this accurately by marking both sides of the tube. First start by using a smaller drill bit to get an accurate first hole, then open the hole to the needed size.
This is where patience comes in, it's better to mark twice and drill once. You can't un drill a hole.

The photos gives me more credit than I deserve. The cuts are a bit rougher than what the photos show them to be.
As you can see on my sequential shifter I made an error while marking out the top cover and you can see a gap at the shifter side of the cover.

There are quite a lot of ways you can do precision cuts and holes with just hand tools. Patience is the key.
Also working along side machinists and metal workers helps to get tips.

Cheers guys

The slide pots were sourced from element14 http://au.element14.com/webapp/wcs/...tegoryId=800000002959&langId=43&storeId=10184

There is a variety of sizes and values, I used the 10k 60mm ones.

Love the "Terminator" look of your kit.
Something about being able to see the workings and having shiny metal all around is cool!

Little bit of an update, the frame is coming along nicely. I mounted the motors in that fashion because I couldn't be bothered opening up the motors and changing the internals for LHD and RHD.


This is how Iv'e mounted the struts. I used some plastic tubing as a spacer because if you secure the rose joints with a nut either side it actually limits the movement of the joint.
With the spacers the joints can move to almost the entire motion range of the joint but more importantly do not foul at the limits of the rigs motion. I'll end up replacing them with
a metal sleeve as the plastic ones won't last very long.



Cheers

@Alexey - something you can try is reverse the lock nuts so that they face the rose joint, the bevel on the lock nut gives just enough clearance for the rose joint bearing.

Your angles look larger than mine, I admit, but something to try.

Actually that's a good idea noorbeast! The conical spacers shouldn't be too difficult to make, just a bit time consuming without a lathe.

Things are coming along nicely @Alexey . Looking good.
As for mounting the motors, don't the gearboxes have a hollow shaft? You should be able to mount them the same way, or am I looking at this wrong?

They do have a hollow shaft but one side protrudes out further than the other. You can't mount the lever arm on the other side.

I am using 12mm bolts, so that's 0.7mm under size.

Actually I lie, they can mount on that side but because of the way i have made the motor mounts it would have fouled on them. Alternatively I could have just spaced out the arm further.
Hindsight is a wonderful thing....

I am surely going to make a second version of this sim. This is my first attempt at making anything like this so I've been running into all sorts of issues that could have been avoided if I'd thought about it for long enough but I suppose one of my vices is that I am just not patient enough! Once I see a way of doing something and it will work the way it needs to work I'll generally stick with it. Then not a moment after I'll see that if I'd spent another 10 mins I could have done it simpler, neater and stronger.

Thanks for the offer but I'll have to pass. Someone else might need them more than me, I should be able to make them up in less than an hour with a linisher.

Yes you can! I have with those motors, I didnt bother changing it around, a long bolt to compensate and allow the motors placed the right way
Look at the photo.

Yeah i corrected myself after I ran out to double check, I'll see if I can switch them around after. Just have to weld up another arm that's got a longer bolt.

That always happens. Even if you spend ages thinking about a certain thing and finally have it figured out, the minute you start building you realize that there IS another way...thanks Murphy!

More progress.

Yes the center support is on a slight angle, cause stupid me didn't align the driveshaft properly when I began welding it. Must have moved it as I started the weld. It doesn't
look substantial but my weight doesn't even bend it the slightest.


Motors mounted same way Had to make new arms, made them in three positions, 60mm, 90mm and 120mm. They are sitting at 90mm at the moment, I'll se how it performs once I get the wiring side of things done.


Aluminium conical spacers made, ty noorbeast for the idea.



And now for the pièce de résistance
I got a free clutch master (no cap, not original reservoir, ill find a cap later), a cheap ($15) bathroom scale for the strain gauges and reused most of the original brake pedal to create a hydro pedal.
Originally I was thinking of sensing the braking force applied via a caliper but when forces exceed the 250kg mark, strain gauges get expensive. So I decided mo make a bit of a lever system that applies pressure to 2 strain gauges at both corners (full bridge) and outputs a signal which can directly replace the original pedals on a logitech system. So no funky business with software. The same will apply to the clutch as it will run on a logitech joystick throttle axis. The brake pedal feels amazing, it's got that slight bit of slack at the very start and then gets very heavy shortly after, almost identical to my car!




Just waiting now for my couplers to arrive so that I can make up a bracket to fit the pots. During that wait I'll work on the base of the sim and fit all the electronics plus I'll get some adjustable feet mounted.