Train GBC:- Mechanical Versus EV3 Control ( Discussion Thread )

[doug72]

Train GBC:- Mechanical Versus EV3 Contro ( Discussion Thread )

I have posted this on the general forum for Comments & thoughts on this from a wider audience.

I see more & more GBC modules using EV3 control on videos taken at various Lego GBC conventions.

With some GBC Train modules it is impossible to control them mechanically no matter how hard you try.

EV3 offers a solution with the ability to precisely set the movements, timing and positioning.

Mechanical control is dependent on getting synchronisation using gearing which can be quite complex.

Comments  & discussion please.

Edited May 21, 2021 by Doug72

[dr_spock]

Don't forget the Mindstorm RCX and NXT back in the days. Plus 9V LEGO train tracks.

Powered UP works pretty good at a lower price point than EV3 or Spike.

 

I guess it's a do you like building carburator or fuel injection gasoline engine?  

It could be easier to fix software bugs than rework mechanic hardware. It can be more interesting for the viewer to see mechanical mechanisms in action.  Although, you could put up a debug screen to show which part of the code is executing to the viewers.  Know your target audience to put on a good show.  

[Toastie]

3 hours ago, dr_spock said:

Don't forget the Mindstorm RCX and NXT back in the days. Plus 9V LEGO train tracks.

Powered UP works pretty good at a lower price point than EV3 or Spike.

I take the freedom to fully second, what @dr_spock has said. Not only the citation above, but his entire post. Fully.

Mechanics is beautiful. Truly beautiful. But mechanics combined with some sort of "intelligence" is so much more.

Also, I like to stress @dr_spock's point of "don't forget": In essence, TLG is doing the same thing >over and over< again: There are X sensors and there are Y actuators (and X and Y are not that far away from "3") - and some brain in between. Sure, the brain is getting bigger and more powerful; at the same time, more memory demanding operating systems are used. Think Python and compare to LEGO "machine code" = byte code. Plus other programming languages like C or C++. And this is absolutely OK. Nevertheless, and don't get me wrong, GBC machines don't need super computing power, they need reliable >synchronization<. As far as I know, I never did GBC(!) but enjoy every video available on the net ;). Reliable synchronization depends much more on intelligent sensor reading and response, of course in accord with temporal requisites. As an example, an RCX is really "fast", when you let it off the leash.

I believe that virtually all PBricks [Scout, Spybot (BTW, these feature >two< internal, fully controllable motors!), RCXs(!), NXTs(!), and yes, EV3s and the PUp hubs)] are very useful within GBC applications.

Once again, I am just echoing what was said by a very experienced member of this board.

All the best
Thorsten

Edited May 21, 2021 by Toastie
Oh well, it was a long day ...

[doug72]

@dr_spock @Toastie

Thanks for your comments which I agree with.

RCX, NXT 9 volt rails were way before the time I joined the Eurobricks Technic Forum.

My early builds were cranes & construction equipment and later simple GBC then the Akiyuki Train GBC system.

One of my most complex was the Though GBC Rotary Dumper which is fully mechanical controlled. -

I have rebuilt / improved the rotary dumper part for potential future use.

Now mainly now interested in Train GBC and have built modified / improved modules using fully mechanical solutions.

I have tried many times to make a simpler Akiyuki Transfer Crane & also a Swing Loader module using mechanical solutions alone which either failed or not very reliable.

I tried trip levers / PF switches etc but none worked & run out of ideas so turned to EV3.

As I had an unused Xmas (2019) EV3 Mindstorms Set I finally gave it a try and began to figure how to use it.

Early problem was the instructions & programming were for Microsoft OS.

I use Mac OS (Big Sur) and finally I found the correct instructions using Lego Classroom & then Home versions and how to use & program it.

I will only use EV3 only when all else fails !

Edited May 22, 2021 by Doug72

[whitepen]

I love EV3 but for GBC's I prefer a mechanical solution. 

[aeh5040]

Mechanical FTW.

[howitzer]

I haven't had much interest in train modules, but more generally I'd say that when you do a GBC, you should always aim to make it fully mechanical OR if you're going to use EV3 or whatever, you should find something that would take advantage of the possibilities that the smart bricks offer. In other words, do things that are patently impossible with purely mechanical systems. Classic example is the colour sorter that puts differently coloured balls into different tracks, as there's no mechanical way to distinguish between balls based on their colours. I guess train systems are a bit of a problem here, as in theory they could be made to work as purely mechanical system but reliability is going to be an issue and it's much easier to make the system reliable with smart bricks.

Taking advantage of the smart brick in GBC's has been in my mind for a while but I don't really have any ideas which couldn't be made to work purely mechanically so I haven't got around to actually doing anything with it.

[doug72]

On 5/24/2021 at 6:40 AM, howitzer said:

 

Agree your comments,

A stand alone GBC driven by one motor is relatively easy mechanically.
With train GBC it is more complicated.

Generally the train car powers the GBC module which OK if it is for input to out sides with the train car released by its own reverser unit.
Possible to add a separate PF motor to assist triggered by the train docking if extra power required.

When a module requires a reversal of motion such as in the Transfer Crane & Swing loader modules, it requires an additional mechanical reverser to achieve this powered from the train car, as this changes over there is a short dwell period which in turn gets the whole system to get out of sync.

I have built / modified many Train GBC modules which function OK and stay in sync all driven by the train car.

However the Transfer Crane Loader & Swing Loader have me stumped, 
I tried a square drive & failed, so EV3 was the solution.

Still hunting for lost balls !!

Edited May 25, 2021 by Doug72

[ord]

On 5/24/2021 at 3:40 PM, howitzer said:

Classic example is the colour sorter that puts differently coloured balls into different tracks, as there's no mechanical way to distinguish between balls based on their colours.

Akiyuki - "hold my beer":

 

Just kidding, I agree with the point that you were making. 

[howitzer]

2 hours ago, ord said:

Akiyuki - "hold my beer":

 

Just kidding, I agree with the point that you were making. 

Haha, nice  Though technically it's still based in the shape of the balls, not their colour, even if the colour happens to match the shape.

Now I'm expecting someone to build a mechanical separator that takes advantage of the subtle differences in the texture caused by printed/unprinted areas of the balls...

[ord]

true true