LEGO Fallercar consept

[F0NIX]

Has anyone else here tried to make an LEGO Fallercar?

A Fallercar is a car that has a automated steering mechanism made of one magnet that are attached to the front of the steering and as the car follows a metal string hidden in the ground the front wheels steers after that string in curves. This is often used in non-LEGO train layouts where they also want the cars to move around.

Here is a place where they have used a lot of this: http://www.miniatur-wunderland.de/

After seeing all those videos on YouTube from Miniature Wunderland in Hamburg (Germany) I wanted to try this in LEGO.

Actually this idea came to me for a few years back but I never got around to try it.

First of all I set a few criteria that I wanted this project to follow:

1. Have to be automated steering.

2. A small car that could drive around in a minifig scale city, had to fit on the regular LEGO-road base plates.

3. As far as possible use only LEGO parts except for the metal string under the road.

For size I want it to be 6 wide or less. For length it could be a long truck with trailer or a van.

Then on to the first consept car. I met a few problems: the LEGO steering has a lot of friction and the LEGO magnet is too weak. The other problem is that to be able to turn this small car in the tight turns in a city it can not have a stiff rear axle that drives both wheels, because that would prevent it from taking those sharp turns. So then I made a split rear axle where the motor only drive one wheel. The problem then is that its hard to get enough traction to move the car forward. I have to think out some sort of "slip-differential" that would fit in 2 stud space between the wheels...

Here is a picture of what I have got so far:

(Click on a picture to see a larger version)

If you have any suggestion or ideas on how to make this work I would be very happy if you comment on this.

On Brikelauget.no there is another guy (Ostehovel) also trying this, but his idea is using two halleffect sensors in the front following a magnetic strip. And it is controlled by a programmable ship called Teensy. So he is going with the mixed non-LEGO and LEGO version.

I have also made a project with a small PF-controlled car. More on that in another thread later.

[DLuders]

Take a look at Sariel's "3-Studs-Wide Differential Bracings" webpage.

[Brickend]

If you use two 7 stud long thin technic liftarms, you can build a differential housing that is only 4 studs wide, which would fit. It wouldn't be very strong but it doesn't look like it needs to be.

Traction is an interesting problem, where the magnet it is now (when it works), it will always try pull the rear wheels off the ground as it acts as a counterweight/attracted to the road. I can't work it out but I'm assuming that adding a additional fixed magnet to the rear could actually improve the tenancy to steer???

[timslegos]

Very interesting concept. Although I can't think of anything at the moment, I am looking forward to the progress

Tim

[dr_spock]

I think you have asked this before in the Town section.

http://www.eurobricks.com/forum/index.php?showtopic=57230

[KEvron]

i have seen this done before, though i couldn't tell you where. a micro scale train. it had a christmas theme, i think. if i recall correctly, the wheels were fixed, but it worked just fine regardless.

KEvron

[F0NIX]

Take a look at Sariel's "3-Studs-Wide Differential Bracings" webpage.

The problem with those differentials is that they are bigger then the wheels and take up WAY to much space in the car. I need space for the motor and batterybox too :)

I have tried one with just liftarms on the sides, but because of the hight I had to either mount it higher than the wheels because of the size of the differentials, or I have to use bigger wheels. I wish to use wheels as small as possible. Hope to use wheels smaller than on the prototype I have made until now.

One goal is to fit all this into a small car on the size of the Vestas van in the set 4999.

[Zerobricks]

My advice. use harder rubber on rear to ease sliping :)

[DLuders]

One goal is to fit all this into a small car on the size of the Vestas van in the set 4999.

@ F0NIX: The Vestas van appears in the picture below; it appears to be only 6 studs Wide x 17s Long x ~8s High. The smallest, functional Power Functions car I've seen was the 8183 Track Turbo RC car, which uses the bb396c01 "Electric, Motor RC with Steering Mechanism and Receiving Unit, Dark Bluish Gray Base" (pictured below). It has a built-in Power Functions battery box, Receiver, and steering mechanism but is 8s W x ~21s L x ~7s H. If you used NON-LEGO parts, maybe it's possible to make the Fallercar you want.

I recommend using a 9V battery with this adapter to save space and weight:

[Brickend]

You wouldn't need a steering motor as the whole point of this concept is that the steering on the vehicle is magnetized, doesn't look like RC is a requirement at all. The 9V idea is good though.

Looking at a real version, there does not appear to be a diff of any kind.

http://www.midlandred.info/fcs.shtml

Quite an interesting challenge.

[le60head]

Thats a pretty good idea.

I'll be delighted to see it work!

Heres a link to my minifig scale RC bus: http://www.eurobricks.com/forum/index.php?showtopic=62632

For the reasons stated in this topic, i used only 1-wheel propulsion, and no diff since the model is 7-wide.

I hope my solution would give you some inspirations.

I'll be keeping an eye on this topic. Good luck!

Best regards,

legohead

[Burf2000]

I actually have this on my todo list as I think they are very cool.

[kyphur]

I recommend using a 9V battery with this adapter to save space and weight:

The only problem I see with recommending the pp3 > 9v Adapter is that it only works in conjunction with the IR Receiver.

[Splat]

I thought that I would put together a proof-of-concept to see if I could get something working.

Here is a quick video that I put together, and the description that I wrote on YouTube:

A proof-of-concept to see if I can replicate part of the Faller Car System using Lego Technic -

http://www.faller.de/App/WebObjects/XSeMIPS.woa/cms/page/pid.14.17.109/lg.en/...

All parts are 100% Lego, except for the strong magnets at the front of the vehicle, and the track (made out of a bent coat hanger, cardboard, and packing tape).

As the vehicle drives forward, the magnets at the front are attracted to the metal track, which steers the vehicle accordingly. Ideally, the metal track would be built into the road surface and be invisible.

Only one of the rear wheels is powered by the Lego Power Functions M-Motor, and is fixed to the axle using a 24 tooth crown gear that grips the side of the rubber tire. The wheel on the opposite side can spin freely.

Although the video shows the vehicle going fairly slowly, it also works surprising well at faster speeds and stays on track, but I dodn't have a long enough track to show this.

One of the key design decisions was to make sure most of the weight was towards the back of the vehicle, so that the drive wheel has enough grip, and so that the steering is light enough to move freely.

Some additional notes:

• My vehicle is a bit wider than 6 studs, but you should be able to reduce the width if you make the steering mechanism a bit smaller and use skinnier tyres. The length could also be reduced by using a 9V battery and adapter, as DLuders suggested above.
  
• I had to use a number of strong magnets to get my vehicle to follow the track nicely, but I don't think that Lego makes anything that strong.
  
• My wire track was above the cardboard base, so there was a bit of problem with the clearance between my vehicle and the track at times. If the track was under the road, then this shouldn't be a problem, although you might need to adjust the magnets again. Unfortunately I didn't have any Lego road baseplates to test with.
  
• The turning circle of my vehicle is quite large, but that is mainly influenced my the length of the wheel base and the steering geometry I used. Play with these and I'm sure you could get the vehicle to have a tighter turning circle. One thing that I noticed on some of the Faller vehicles is that they have the magnet out in front of the vehicle quite a bit, which might be something to consider.
  
• As I don't have many Lego system parts, I haven't put a full body onto my vehicle, and this might make it behave differently. One key thing that I found was that most of the weight has to be over the back wheels for it to work properly.
  
• I had my battery box set to the slowest speed, so the motor didn't have very much torque. By incorporating a worm gear, you could have the motor spinning faster, but still driving the vehicle at a reasonable speed, and be able to carry a heavier load (eg. the weight of a Lego body).
  

The only problem I see with recommending the pp3 > 9v Adapter is that it only works in conjunction with the IR Receiver.

As Philo mentioned in this post, the 9V battery should be able to power the PF LEDs or PF motor in addition to an IR Receiver, if it is wired correctly.

[timslegos]

Looking good! the next step will be to buy some base-plates!

tim

[F0NIX]

Splat, nice implementation! Good to see that it IS possible :)

Now I just have to order some neodyne magnets....

And I have also found other types of batteries that takes up less space, but then we are going non-LEGO. I have to consider how much non-LEGO parts I want to implement in this project. But good to see that not only I see this project useful and fun :)

[kyphur]

As Philo mentioned in this post, the 9V battery should be able to power the PF LEDs or PF motor in addition to an IR Receiver, if it is wired correctly.

I agree with that point, just wanted to point out that the ones being sold don't have that feature.