Remotely operating function changes in Technic models.

[beelzibus]

Hi, I'm looking at ways of improving certain aspects of my builds and wanted to ask the collective mind their thoughts on a few specific subjects, this being one of them;

I'm a big fan of remote control, integrating PF units as much as possible into my builds.

Initially it seems that for simplicity, each function run by it's own motor/s and using one channel on a remote seems to be the simplest way; One remote can control eight functions, so that's eight motors (at least). However constraints including space within the model, weight of the finished model and not to mention the cost of multiple motors and suddenly it seems to have it's drawbacks.

Except eight channels isn't always enough, some models require more than eight, which means manually operating pole reversers, pneumatic switches of driving ring switches. Thoughts then move onto complex gearboxes, such as those used on 42043 (Mercedes Arocs), working four individual functions from just one motor is certainly being economic both with parts, weight space and money, however changing from one function to another clearly relies on the outside influence of a switch manually operated, and negating RC control. Or does it?

Are there any examples of MOCs where builders have successfully managed to control ordinarily manual functions, such as sliding driving rings, or electric pole reversers, by coming up with some kind of operating mechanism, that in itself can be controlled remotely.

This of course is of little benefit if an individual motor is used to change over each pair of functions, but if one motor, could be used to drive (for example) four functions, each in turn switched mechanically by remote control from the power of just one other motor, at least we'd have halved the number of motors. The more functions that could be run and switched by each pair of motors the better of course.

Thanks in advance for any thoughts, images and such like anyone would like to share on the subject.

[Zerobricks]

8043 is an excellent example of remote multiplexer, where you get 6 functions from 4 motors.

[GroundskeeperWillie]

I've done a 2-in-4-out multiplexer in my Xerion MOC. Basically it just Sariel's latest gearbox modified to multiplex instead of changing gears. More details here: http://www.eurobricks.com/forum/index.php?showtopic=114684&hl=

[dhc6twinotter]

The 8043 Excavator is a good example of how this can be achieved. It uses 4 motors to drive 6 functions. It used 3 motors to drive the functions, plus a motor to switch between the functions.

I used a similar setup in my Backhoe, although I used 4 motors to drive 8 functions, plus a motor to switch between functions.

So, with a single gearbox, you can build a moc that has 14 functions. You would have 7 motors going through a two position gearbox, plus one motor to switch the gearbox.

You can also use more then one gearbox for many more functions, but playability gets worse.

Banks of PF switches or pneumatic valves can also be used to duplicate functions. Some people have also used a motor to turn on/off battery boxes.

Just my $.02.

[Zerobricks]

I think with good engineering and a servo you could actually make a switch with 3 functions, giving you a total of 21 functions

[dr_spock]

Or control power to banks of IR receivers and multiplexed motors.

[GroundskeeperWillie]

There are in fact numerous designs out there. Try googling 'lego multiplexer' and look the image results.

Examples:

An NXT version. This approach may also work with a PF servo.

What looks like a very low torque version. But cool nonetheless.

I think a common trait for these designs is that they take up a lot of space and it may be difficult to incorporate them in a MOC. If you have a large number of outs in one place you still need to transfer the power to where it is needed.

[Jeroen Ottens]

A few years ago I designed a remotely operated Liebherr LTM11200. In the superstructure a multiplexer mechanism was used. 4 motors were used to drive 12 functions (1 motor switches to four different states in which the three other motors drove each one function). The concept is easily scaleable. For each motor that you add you get 4 more functions that you can switch remotely.

Here is the link to the topic:

http://www.eurobricks.com/forum/index.php?showtopic=89963

[beelzibus]

8043 is an excellent example of remote multiplexer, where you get 6 functions from 4 motors.

Thank you, although I was aware of 8043, I have never looked at it's construction, or functionality and that's exactly the kind of thing I was looking for. I've now built the gearbox of that, and it's certainly a useful mechanism. It's not quite the solution, but it's a good start.

I've done a 2-in-4-out multiplexer in my Xerion MOC. Basically it just Sariel's latest gearbox modified to multiplex instead of changing gears. More details here: http://www.eurobrick...opic=114684&hl=

That's a fantastic piece of design (well it would be if Sariel designed it.) it doesn't suit my needs though having the four functions sequentially selected like that instead of in any order at will.

Banks of PF switches or pneumatic valves can also be used to duplicate functions. Some people have also used a motor to turn on/off battery boxes.

Are you meaning just swapping out the sliding driving rings for pole reversers or Pneumatic switches?

I think with good engineering and a servo you could actually make a switch with 3 functions, giving you a total of 21 functions

Please can you elaborate on this. Thanks.

There are in fact numerous designs out there. Try googling 'lego multiplexer' and look the image results.

I think a common trait for these designs is that they take up a lot of space and it may be difficult to incorporate them in a MOC. If you have a large number of outs in one place you still need to transfer the power to where it is needed.

I have done as you say, the word multiplexer was not in my vocab before, now I've looked at the kind of things shown I agree with your second statement, most seem large and of limited use in MOCs.

A few years ago I designed a remotely operated Liebherr LTM11200. In the superstructure a multiplexer mechanism was used. 4 motors were used to drive 12 functions (1 motor switches to four different states in which the three other motors drove each one function). The concept is easily scaleable. For each motor that you add you get 4 more functions that you can switch remotely.

Here is the link to the topic:

http://www.eurobrick...showtopic=89963

Wow, Jeroen, that's a magnificent effort.

I feel your pain however with regards to functions that don't work as planned; The MOC I'm building that all this is for, has in many ways similarities with yours, it's not as complex, or as sizeable, however it's complexity and size has reached the limits it seems of the plastic pieces we use. Increase size, functionality and complexity and you increase weight, weight bends parts and overloads gear trains, it can be very frustrating.

I'm very interested in some more details about the mechanisms in your Liebherr. A few questions if I may:

In what way can you add 4 more functions per additional motor? I've studied your ghost image of the superstructure but can't decipher the switching side of things. I have read and reread the thread but perhaps I'm missing something.

Thanks for all your input on this.

Edited October 11, 2015 by beelzibus

[BachAddict]

I'm very interested in some more details about the mechanisms in your Liebherr. A few questions if I may:

In what way can you add 4 more functions per additional motor? I've studied your ghost image of the superstructure but can't decipher the switching side of things. I have read and reread the thread but perhaps I'm missing something.

Thanks for all your input on this.

How Jeroen's gearbox works: There are six driving rings, but they are split into two groups. Only one side of one group is engaged at a time, in a cyclical manner like Sariel's latest gearbox.

The three function motors each drive two rings, one in each group. If you add another motor, you can add another driving ring on each side, each giving two more functions.

[beelzibus]

How Jeroen's gearbox works: There are six driving rings, but they are split into two groups. Only one side of one group is engaged at a time, in a cyclical manner like Sariel's latest gearbox.

The three function motors each drive two rings, one in each group. If you add another motor, you can add another driving ring on each side, each giving two more functions.

Ah, so basically Sariel's Shifting mechanism, but applied to two shafts each with one or more driving rings, correct? So whereas the two shafts in Sariel's box are interlocked in various ways to effect ratio changes between input and output, in this case the two shafts are separate and each driving ring is operating a pair of functions separate from any other. I think that makes sense. I'd love to see some pictures.

[Blakbird]

Desert752's Feller Buncher has 18 motors and uses a motorized switching system to turn on/off different battery boxes and IR receivers.

[beelzibus]

Desert752's Feller Buncher has 18 motors and uses a motorized switching system to turn on/off different battery boxes and IR receivers.

Yes I spotted that last night and my brain promptly exploded. i need some time to get my head around that one. It defies belief.

[KirTech LAB]

Such a problem was discussed in my Grader topic - http://www.eurobricks.com/forum/index.php?showtopic=84978&st=25

Unfortunately my pictures are broken but maybe you can find something interesting in the text. I'll try to repair the pictures.

[Jeroen Ottens]

How Jeroen's gearbox works: There are six driving rings, but they are split into two groups. Only one side of one group is engaged at a time, in a cyclical manner like Sariel's latest gearbox.

The three function motors each drive two rings, one in each group. If you add another motor, you can add another driving ring on each side, each giving two more functions.

That is a spot on explanation, you can add motors until you run out of channels, so this system is extenable to 28 functions using 7 drive motors and one switching motor. I don't have more pictures at the moment. However the switching mechanism is similar to the one I used in my Alpha Romeo 4C Spider (that has a slightly different configuration of the knobwheels).

I still haven't abandoned the project entirely (in fact it is still not taken apart). If I really abandon it I will release the LDD files for others to play with. The other option is that I will finish it and update & release the LDD files of the fully functional MOC (I don't phantom making instructions for this monster myself).

[dhc6twinotter]

Are you meaning just swapping out the sliding driving rings for pole reversers or Pneumatic switches?

Sort of. If you use the pole reverser method, each function would have its own pole reverser and motor. Half the pole reverser would be in the off position, and the other half would be on. Another motor is used to determine which half is on or off. So, if you had 8 receivers, you could use 14 pole reverser (doubled up on the receiver outputs), 14 motors, and one additional motor to switch which half of the pole reverser a are in the on position. The top portion of the diagram Blakbird posted has a similar layout for four of the motors.

For pneumatics, you could have motors connected to 7 valves. Each valve output (two per valve) is connected to the input on another valve, which is then connected to the cylinders at each function. Half the valves are in the open position, and half the valves closed. A motor is used to determine which valves are open or closed. So, if you were to use pneumatics on all functions, you would have

21 valves.

I'm working on a road grader that uses the above method, so I'll have pictures up in a bit.

[KirTech LAB]

I'm working on a road grader that uses the above method, so I'll have pictures up in a bit.

I was reading your comments in my old grader topic when I was repairing the pictures. I'm glad to hear that you are building such model! Can you show some pictures? :)

PS: the old topic is repaired

[JJ2]

How Jeroen's gearbox works: There are six driving rings, but they are split into two groups. Only one side of one group is engaged at a time, in a cyclical manner like Sariel's latest gearbox.

The three function motors each drive two rings, one in each group. If you add another motor, you can add another driving ring on each side, each giving two more functions.

I have done the same thing and it works very well.