Rims

RPI Geek · 03-26-2006, 02:13 AM

I didn't know which subforum to put this in but this one is the closest ... I hope it's not a repost: http://www.leftlanenews.com/2006/03/...-go-high-tech/
I don't have anything else to say about this one: enjoy

moesbarn · 03-26-2006, 02:19 AM

22" package with Pirelli tires ($12,500.00)
24" package with Pirelli tires ($15,000.00)
26" package with Pirelli tires ($19,500.00)

thats mad, but look at the price :S how possible would customising normal wheels to do this be?

RPI Geek · 03-26-2006, 02:48 AM

Someone who posted on that page thinks it should be a weekend project for someone with the right skills. For someone like me, I think it might take a week or 2.

Hmm, Maybe when I pick up a set of steelies for my car I'll try this on a hubcap

moesbarn · 03-26-2006, 03:37 AM

nice, well if you give it a go, please post how it goes, and how you go about it, would be mad to pull this off for a relatively small cost.

slaya786 · 03-26-2006, 12:40 PM

The one thing I can't figure out is how they get the wires from the wheel to the car? especially while the wheels are turning, won't it tangle up or something

DJiK · 03-26-2006, 01:22 PM

Quote: Originally Posted by slaya786

The one thing I can't figure out is how they get the wires from the wheel to the car? especially while the wheels are turning, won't it tangle up or something

To overcome this problem, I would use an RF (Radio Frequency) receiver on the wheel. It'd be positioned somewhere towards the center (for centrefugal reasons).

When programming this, one must know the wheel's diameter (incl. the tire) and the vehicle's speed in order to set the right refresh frequency on each LED. BTW, the LEDs on the outside of the spoke obviously spin faster than the ones towards the center.
All in all, there's some programming, some electronics, and lots of trigonometry involved... Nothing that the typical mp3Car'er can't handle.

Plus, keep in mind that most of us have the computers on board already.

RPI Geek · 03-26-2006, 11:51 PM

Quote: Originally Posted by DJiK

To overcome this problem, I would use an RF (Radio Frequency) receiver on the wheel. It'd be positioned somewhere towards the center (for centrefugal reasons).

When programming this, one must know the wheel's diameter (incl. the tire) and the vehicle's speed in order to set the right refresh frequency on each LED. BTW, the LEDs on the outside of the spoke obviously spin faster than the ones towards the center.
All in all, there's some programming, some electronics, and lots of trigonometry involved... Nothing that the typical mp3Car'er can't handle.

Plus, keep in mind that most of us have the computers on board already.

I'd put a microcontroller on the wheel like you said, with an RF link. I wouldn't use the wheel's speed because if you're off even a tiny bit the image will rotate. I'd use something like an accelerometer to tell when the wheel is at the bottom (max value because of gravity), or a magnetic coil like on a bicycle speedometer. You'd want to be careful about that method though, because if the thing came loose it would hit your wheels and disk brakes and everything... not fun.

As for converting the cartesian coordinates to polar, that's really easy (probably because IIAME...I Am A Mechanical Engineer). The calculation would only have to be done once, too. The thing that I would really need help with is making the circuits and picking components that can switch on and off fast enough to make a semi-sharp picture. Anyone care to start workin on this project with me?

DJiK · 03-27-2006, 04:07 AM

I'm only willing to help out with ideas... Besides, we're 2,400 miles away from one another to begin with.

Here's something I haven't noticed before:

Quote: Originally Posted by Dub

and [the wheels] are powered by the vehicle electrical system so there are no batteries to run out or change, ever.

Suddenly I have second thoughts about tangling wires... Unless, if a car has a brake pad sensor (to tell the driver he's running out of brakes), maybe you could hook up to it; altough I think it's stationary as well.
On the other hand, circular motion could be coverted into electrical energy by using a dinamo, but that would ruin gas mileage and be very difficult to mount.

Oh, and your idea using a magnetic coil makes more sense than the accelerometer because the latter experiences enough g forces already (it might not notice the gravitational field).

As far as the fast-swiching components you're referring to go, those swinging/rotating digital clocks don't seem to have some sort of "special" LEDs.

Granted, most of them don't use RGB LEDs either, but worse come to worst you could use Red, Green, and Blue Mini LEDs closely positioned together to get the proper refresh rate on each (especially on the outer diameter).

A couple more things to keep in mind:
- The actual product has 3 LED-filled spokes per wheel. I'd assume that the more spokes (w/ LED bars) you have, the brighter, sharper, and more stable your image would appear.
- The ad/order page doesn't talk about this, but you must decide at how many RPMs minimum should the image come to life.

GreenBeast · 03-27-2006, 04:41 AM

it'd be cool if the images were rpm dependent, then as you went faster they could change

RPI Geek · 03-27-2006, 02:11 PM

Quote: Originally Posted by DJiK

I'm only willing to help out with ideas... Besides, we're 2,400 miles away from one another to begin with.

Here's something I haven't noticed before:
Suddenly I have second thoughts about tangling wires... Unless, if a car has a brake pad sensor (to tell the driver he's running out of brakes), maybe you could hook up to it; altough I think it's stationary as well.
On the other hand, circular motion could be coverted into electrical energy by using a dinamo, but that would ruin gas mileage and be very difficult to mount.

Oh, and your idea using a magnetic coil makes more sense than the accelerometer because the latter experiences enough g forces already (it might not notice the gravitational field).

As far as the fast-swiching components you're referring to go, those swinging/rotating digital clocks don't seem to have some sort of "special" LEDs.

Granted, most of them don't use RGB LEDs either, but worse come to worst you could use Red, Green, and Blue Mini LEDs closely positioned together to get the proper refresh rate on each (especially on the outer diameter).

A couple more things to keep in mind:
- The actual product has 3 LED-filled spokes per wheel. I'd assume that the more spokes (w/ LED bars) you have, the brighter, sharper, and more stable your image would appear.
- The ad/order page doesn't talk about this, but you must decide at how many RPMs minimum should the image come to life.

I think a magnetic coil is a better idea than an accelerometer, too. I was just throwing ideas out

I would probably have it use batteries of some sort... Although if we DID use a dynamo the power would cut in when it's spinning, so minimum RPM's are a non-issue... and we could have it serve dual use as the position sensor, so we wouldn't have to add another one. I just can't think of a good way to get power to the wheel from the car's electrical system.

The 'fast-switching' components that I'm worried about are the parts that'll power the LED's... I figure LED's are fast because I built a PWM transmitter in one of my classes and it ran at something like 15 KHz... I just don't know how to control it digitally like would be necessary for this..... It's not my field of expertise. Given a circuit diagram, I have no problem building and testing it, but designing the circuit is very tough for me.

DJiK · 03-27-2006, 02:43 PM

I found another video.

Here's how you'd get power or anything else to the wheels...
I'll try to describe it:
Circular rails... They'd be positioned on a plate, and brush contracts will be touching them as the plates spin.

Picture a rotating circular target. Each circle in the target is a copper contact rail. Now, you're putting a brush-like (or old style key-like) pin with stationary contacts that are touching the rings in the target. Just like a turntable player with multiple needles.

If you only need only two wires (+ & -) then there's really not much to it.
The key is choosing the right components to minimize heat and corrosion so that the contacts stay fresh longer.

RPI Geek · 03-27-2006, 03:17 PM

Yes, that would work, but it's not really an option for something that should just be a bolt-on thing. Plus there are issues (like you said) with sparking, corrosion, dirt, interference with the other (more important) things on the wheels like the brakes...

I suppose I could use a transformer of some sort, but I'd really rather modify the suspension as little as possible.

Also, my first iteration will probably go on hubcaps: cheap ones from Wallyworld. Preferably hubcaps that can snap on to steelies. I don't want to go mounting LED's to my nice alloy 5-spokes.

Fusion-One · 03-27-2006, 03:38 PM

why not use the power of the wheel rotating to generate electricity? A small DC motor on its side with a weight hanging off the shaft always trying to keep it pointed towards the ground would have the effect of spinning the shaft. I'm sure you could generate enough power to run LED's and a microprocessor.

I have a Powerball which lights up LED's just from your hand movements.. and they light up BRIGHT.

Seems like the easiest way to power the device.. you could have a Li-ION battery for when the car is stationary.

RPI Geek · 03-28-2006, 12:18 AM

Quote: Originally Posted by Fusion-One

why not use the power of the wheel rotating to generate electricity? A small DC motor on its side with a weight hanging off the shaft always trying to keep it pointed towards the ground would have the effect of spinning the shaft. I'm sure you could generate enough power to run LED's and a microprocessor.

... ...

Seems like the easiest way to power the device.. you could have a Li-ION battery for when the car is stationary.

You're forgetting centrifugal force, unless you mean to align the motor with the hub. That's worth thinking about more...

I'll probably use a Li-Ion battery for the first attempt, and work on the power system later.

Fusion-One · 03-28-2006, 12:24 PM

Another suggestion would be to use an LED bar which goes straight across the center.. No hole that way.

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