[TC25] 8479 Barcode Truck

[evank]

12 hours ago, Berthil said:

Thanks for posting. I did not know this although I think I remember this book from my youth. The idea from the book are 'coding strips' rather than gear racks on the road but the principle is of course the same. The strips are probably easier to operate, also because they use a motor and in this model are no motors. So the movement of the model is used for the mechanical movement of tipper and tire dumper through the gears.

I work at a university and teach a course in the history of computing. I explained to my students that this method is analog, not digital. I like you idea of calling the plates/racks "strips", because people tend to think of them as punch cards, which are digital -- the comparison just confuses things. However I am also starting to design a simple Lego punch card method, which different mechanical actions in/out of the holes would make a robot behave as desired -- I'm not saying it would be Turing complete :) but still fun to build.

[mirrorbricks]

Awesome idea, waiting for the final result gear patterns are a perfect representation of barcodes. Miss this kind of features, and that's sad cable system are not really available now, It blew my mind when I was a child

[Berthil]

While waiting for parts and finishing a kitchen rebuild, I've recreated the original 52 building steps of the Barcode truck and tried to add the shrink model parts in the same building steps.

Next is building the dumper arm, I hope it will work properly.

[Lemon]

On 7/24/2023 at 8:26 PM, evank said:

I work at a university and teach a course in the history of computing. I explained to my students that this method is analog, not digital. I like you idea of calling the plates/racks "strips", because people tend to think of them as punch cards, which are digital -- the comparison just confuses things. However I am also starting to design a simple Lego punch card method, which different mechanical actions in/out of the holes would make a robot behave as desired -- I'm not saying it would be Turing complete :) but still fun to build.

Can you explain to me why this method is analog, instead of digital? 

I would expect it to be digital since there the gear racks have discrete teeth, which result on discrete amounts of rotation of the interlocking gears.. Since there are 10 teeth on a 4 stud rack, it kind of resembles a punch card where every 3.2 mm of space in which a tooth resembles a logical 1, or the absence of a tooth a logical 0.

[evank]

Because the input (rack movement) is physically analogous to the output (model movement.)

To be digital, it would have to be abstracted.

One could build that in Lego, but it's not what is happening in the relevant models.

Edited August 1, 2023 by evank

[Berthil]

Started working on the free building instructions while waiting for (PaB) parts. Here the bi-directional gearing for the tire dumper.

Edited August 1, 2023 by Berthil
typos

[Berthil]

I'm happy to report the tire lifting works but gearing needs to be changed so it can be operated with a bit less force. It uses strings through 3mm rigid hoses instead of the cable system. Obviously strings can't push (although they do a little bit) so the tire clamp needs to be opened by hand. But video's from the original model show this was also needed occasionally with the 8479. To finish the model only some roof parts are needed from B&P.

I'm 57 but LEGO still amazes me, think of a concept, design it, build it, finetune it and it works.

 

[Appie]

Flex-system revival in modern times, nicely done. Perhaps a well-placed rubberband at the claw to make the default position open would remove the need of having to open it by hand? Will probably be a fine balance with the force needed for the claw mechanism, but since you're adjusting the gearing for it, it might work out for this too?

[Berthil]

A rubber band crossed my mind but haven't tried it yet because the claws just about pick up the tire. Any resistance and the tire stays on the table. Will see how it goes with new gearing but I expect lower forces so may be also a lower clamp force although that is for the most part related to the weight of the whole arm that needs lifting up. I'll try the rubber band.

[GerritvdG]

Fantastic work, really love the effort you put in everything, the parallel building steps video, videos of the progress and free instructions. Everything we could wish for 

4 hours ago, Berthil said:

I'm 57 but LEGO still amazes me, think of a concept, design it, build it, finetune it and it works.

Indeed! 

[Berthil]

To make the gearing clearer I made the below video out of 146 Stud.io renders and image overlays including realistic rotation of every gear and positioning of elements in every step.

 

Edited August 6, 2023 by Berthil

[SaperPL]

48 minutes ago, Berthil said:

I made the below video out of 146 Stud.io renders

I thought someone has a know how to make those kind of animations in studio, but this is nuts - 146 renders ?!?!

[Kostq]

Yes, gear meshing and rotations must be calculated and done by hand. No automation there.

[Berthil]

Parts have arrived and final model is build. All works well, tomorrow the video and free building instruction will be ready. Very happy with the looks and playability.

[Akassin]

as always - incredible appearance like the rest of your work. I am sure that in the nomination "for originality" the victory is guaranteed to you. It's a very cool idea to turn a barcode into "mechanical coding"

[Zerobricks]

Woah, what a cool project and brilliant idea using racks to program it!

[Berthil]

As a final image, I've put together all positions where the original decals have been used. The decals for the function switch have been used on the road to indicate what gear rack does what.

[Berthil]

The video and free instructions are published. Thank you to TobyMac (Tobias) for making his Rebrickable 8479 Classic Review video material available!

Free building instructions on Rebrickable:
https://rebrickable.com/mocs/MOC-156049/Berthil/8479-barcode-truck-shrink/

I'll be creating a post in the TC25 Entry Topic today.

[SaperPL]

That works pretty good for what it is. You should definitely score the points for originality here.

What surprised me is that you can fail to pick up the wheel. I feel like you either should use a thicker/wider wheel for the presentation, or the grabber should be lower, almost at the ground level.

What I don't like is that you need separate input to return the grabber to default position. This feels off if the gear rack line is supposed to be input for a function and then you have to split a function between two inputs. At this point it may too late for that, but wouldn't it make more sense to figure out some rubber band/wind up motor spring mechanism to return the grabber back to default position once there is no input for those gears anymore? And find a gearing that doesn't add too much resistance to it, but it's enough to push the grabber through the apex point over the dummy code pilot box?

If you'd just have two inputs, then what I feel would be possible is that you could add rails ensuring the truck hits the gear racks properly (maybe even something correcting it through steering), but more importantly if you have pick up input on one side and dump on the other, you could use the same input for both functions, but the difference would be whether you're going at it forward or in reverse. So by tweaking the positions where' you're grabbing the input off the floor along the length of the truck, you may could use the same spot where you're dropping the tire to turn around and pick it up again with the same gear rack input without having to manually place the tire in pickup spot after dumping it.

[Berthil]

@SaperPL Thank you for your feedback. Actually placing the tire manually is exactly what needed to be done with the original barcode set too (demonstrated in the video). In the original model the motor needed to be switched to the other side to let the model drive. So the shrink model comes with exactly the same 'flaws'. Of course designing new road plates with new gear rack positions is possible but for me out of scope for the competition to keep as close to the original model as possible.

Actually the challenge of picking up the wheel manually is fun to do as it requires a bit of practice and skills. Once mastered it is easy to do. The arm cannot be lowered much as it would touch the gear racks. By tweaking the strings it could be lowered a little bit. I wanted to use the same tire to pick up as is used under the model. Again, because this is also the case in the original model. A slightly smaller tire would work better, a bigger one would not fit between the arms and be too heavy.

Edited August 13, 2023 by Berthil
typos

[SaperPL]

Yeah, the original set was really weird so that makes sense to approach it this way. If possible, I would really like to see this perfected after the competition in a way that you don't need all that platforms and just one spot with one gear rack input.

The looks of the model itself are perfect representation of that iconic green look. That detail of green color + decal where the inputs are is a neat touch as well.

By the way, out of curiosity - do you know what's up with that light grey area in the centre of the dumping spot when you're showing it from above at 2:28? Is it a big grey sticker that you later replaced or is it just a video artifact? In other shots it's clear that there are bricks.

[Berthil]

1 minute ago, SaperPL said:

By the way, out of curiosity - do you know what's up with that light grey area in the centre of the dumping spot when you're showing it from above at 2:28? Is it a big grey sticker that you later replaced or is it just a video artifact? In other shots it's clear that there are bricks.

That's a 6 x 6 light bluish gray tile to mark the dumping spot. Could also have been DBG of course.

3 minutes ago, SaperPL said:

If possible, I would really like to see this perfected after the competition in a way that you don't need all that platforms and just one spot with one gear rack input.

Good suggestion, I'll think about creating a much smaller road section with one gear rack, the gear racks are all equal length so should be possible.

[CP5670]

Very cool model. This type of system with programmable gear racks is used in the 8888 idea book. The card slides through the model, which has a slot to allow it to pass through.