Main > Driving & Racing Cabinets
Real Instrument Panels
BadMouth:
I was looking at cheap 5v analog meters on fleabay earlier.
The needle on them looked like it would be very difficult to swap out.
The post it was attached to was recessed and the needle had a few 90 degree bends to bring it out to the face of the meter.
Looks like these might be made the same way. Still useable, but maybe more of a hassle than anticipated.
Not sure if they have enough range of motion to pass for a speedo or tach.
Howard_Casto:
Yeah my thoughts as well.
I would think that with that wave of useless usb gadgets we had a few years back somebody would have made a usb tachometer than we could just hack. Hmm.... maybe I need to check dream cheeky... I know I figured out the protocol for their missile launchers in an afternoon.
BadMouth:
http://www.meterpointer.com/
Not sure if they sell to the public, but at least we can learn what the parts are called.
EDIT: Not sure if 18 degree steps is too harsh, but these tiny buggers are interesting:
http://www.ebay.com/itm/4PCS-Micro-Stepping-Motor-6-11mm-2-Phase-4-Spools-/170979672182?_trksid=p2047675.m1851&_trkparms=aid%3D222002%26algo%3DSIC.FIT%26ao%3D1%26asc%3D163%26meid%3D6269876152546623129%26pid%3D100005%26prg%3D1088%26rk%3D2%26sd%3D170993951598%26
Howard_Casto:
I don't think I've ever seen a two wire stepper before. Not sure how that would work.
In terms of steps if you want it really accurate you'd need one step per mph/rpm.
I actually found some of the stepper motors for gauges online but they were around 30 bucks a pop... the needles were around 10. Then then you'd need some sort of face plate ect...
On the other hand, buy a cheap instrument cluster for 30 bucks and you've got the needles and steppers for a whole cluster.
So we are back to that again. ;)
Howard_Casto:
Bah! I hate it when I can't sleep, especially when I'm not feeling well.
Anyway since the gauges in a modern car use stepper motors apparently, I thought I'd take a look into the most common one we would all have readily available.
http://www.codeproject.com/Articles/16715/Controlling-Floppy-Drive-Stepper-Motor-via-Paralle
Now all of this is pretty straight forward until you look at the delay he has to use in his code:
--- Code: ---System.Threading.Thread.Sleep(50); // Delay
PortAccess.Output(888, 0);
System.Threading.Thread.Sleep(50); // Delay
--- End code ---
50 Milliseconds per half step, which means 100 ms per step. That doesn't sound like a lot but 1000 ms = 1 true second and each mph/kph would be one step for our purposes.
So if you slam on the brakes and go from 150 to a full stop that's 150x100=15000 ms, which is 15 seconds!
I know that different steppers operate quicker but damn, if this is the acceptable delay I'm not sure what is best.
I looked into CAN bus btw. It's a pseudo dead end. Unless you want to simulate the car's entire can computer (I'm not doing that) you really need the interface box to go along with the instrument cluster. That puts the cost waaaaay back up to the point of where another solution would make more sense.
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