Variable speed with Technic

[Lipko]

Sorry to flood the forums, but I saw that many contestants use variable speed drives.

I'm still new to this new Technic, and I don't know what components to use to achieve the variable speed. Are there electric components for that?

It is a main feature of my entry, and I could only make an eye candy, faking of it, which takes up a large space in the model. This space could be used for another important feature (automatic clutch), which I couldn't add due to the lack of space. Maybe I'd have to time to buy/get those components and rebuild my model.

So, how did you, contestants, achieve variable speed?

Thanks!

Edited April 2, 2012 by Lipko

[Sariel]

I heard some people do it with magic. Others use this:

Buy here: http://www.bricklink.com/catalogItem.asp?S=8879-1

Edited April 2, 2012 by Sariel

[dhc6twinotter]

I used the rechargeable battery pack, which has a variable speed dial on it. You can insert an axle into the dial and connect it to the throttle via linkage or whatnot.

[Lipko]

Thanks for the response. The rechargeable battery pack seems to be a good idea. Can you please give some more details about it? What is the height of it in studs? What is the angle range of the dial?

I try to look into these myself, because that would fit nicely in my model. Maybe I rebuild the thing with a dummy part until I get the real one.

I have another idea, but it seems to be a hack, or even dangerous. I ask this, because there's a good chance that I won't have money to get that battery box, or if so, the shipment will be too late.

So:

Is it possible with a control switch? I know it has discrete positions, but maybe there's a tiny range between the two positions where it can be used for variable speed? I guess the chances for that are quite bad, and I'll just make some sparks and burn down the whole flat if I try... I can only give it a try in the weekend, maybe someone has tried it.

[DLuders]

@ Lipko: You could use a Power Functions Adapter Cable and a Train Speed Regulator, like Sariel does in his

:

The main article is on TechnicBRICKS: http://technicbricks.blogspot.com/2009/05/tbs-techtips-23-connecting-pf-receiver.html .

The 8878 Power Functions Rechargeable Battery Box has these dimensions: 4 studs wide x 8 studs long x 5 studs high.

Sariel has an excellent

of the 8878 battery box:

From his main article on his website, Sariel wrote: "The [integrated speed] dial offers 7 forward and 7 reverse speeds just like the 8879 Speed Control Remote does, but here it has fixed neutral and extreme positions, plus a small position indicator. An axle can be put inside it a single stud deep, just like with PF XL and Medium motors. The dial does not return to a neutral position, and operates regardless of the master button – which means that the box can be turned on or off at any dial’s position. This is a pretty comfortable solution if someone doesn’t really need the integrated speed dial (which will be probably the case of almost all mobile remote-controlled PF-powered constructions)."