2GodBDGlory

Yeah, those parts are mind-bending! I've spent the better part of the day designing and trying to design gearboxes with it, but there's so many options it's hard to determine what's even possible!

Very impressive! I always love seeing complex Lego clocks!

I just added a short poll to the topic, mainly to get people's opinion on how long of a time period we should do, and when the challenge should take place; as well as how many people are interested

Very cool! It seems like these parts have been out for a long time without finding much use, so it's nice to see a fully developed gearbox using them! The selector rings are definitely unintuitive in how they should be set up, so good job making that whole spreadsheet to figure it out! The main thing that stands out to me from this design is the way you were able to use the same selector rings for two different driving rings--you couldn't really do that with the old wave selectors, so I hadn't thought of it as an option! I'll probably be building this today to really see how it works! He mentioned that the middle selector is only used to get a 45 degree offset between the two shafts, and then showed a couple options with knob wheels to get that offset without using that expensive part. -One other thing I was realizing is that linear clutches could be used to get any kind of offset desired, as long as there isn't enough resistance to make them skip. Do you think that could open up more options for gear orders, @Anto? It wouldn't fit in this gearbox, though

So you just have to manually press both drive buttons at the same time?

Wow, three remotes coupled! I am curious! I don't think I've ever seen anyone run that many buggy motors from multiple low-power sources, so nice job!

Fair enough! :) I'll rephrase that: "but it's not a contest, so I don't think it's something we need to worry about"

I hadn't known anything about that Sidewinder X4 Pro, but after looking it up, I'd say it looks pretty cool! All the features one would want, high speeds, good volume, and linear rails on all axes! You don't get linear rails in that price point much, so that's a pretty nice selling point! If you don't want to have to do much tuning, I'd go with the Bambu, but if you want to save money and acquire another hobby, other stuff is good too! My main printer started as a super-basic Ender 3, and I've had a lot of fun upgrading and modifying it, so it can be a fun hobby to start on the lower end! It's just a question of whether you have the interest and energy in getting into that

I'd agree that it's a good idea to get some updated advice, since the printer market is changing fast! Here's three suggestions, all of which are new since the last time this thread was updated: The Ender 3 V3 SE is the latest version of the classic Ender 3, but despite being significantly fancier than earlier versions, it's still available at essentially the same price, at $200 USD currently. It's got good features like auto bed leveling, dual Z-axis, and a direct extruder, but it's slower than my other recommendations at an advertised 250mm/s. Perhaps its biggest advantages are low price and the kind of community support that comes from being part of a long line of super-popular printers https://store.creality.com/products/ender-3-v3-se-3d-printer?sscid=21k8_9erc8& It appears that there's a fancier version, the Ender 3 V3 KE, which has some more smart features for wireless control and faster, advertised 500 mm/s printing. It might be worth it at $280 USD https://store.creality.com/products/ender-3-v3-ke-3d-printer?spm=..collection_90778a1d-d845-4ff0-a8c4-48fded4b7d74.albums_1.1 The Elegoo Neptune 4 is one that a friend of mine got recently, and it's pretty impressive! It's got the same 500 mm/s printing, auto bed leveling, dual Z-axis, and a direct extruder. Perhaps its only downfall is that it requires a little more work, and either a USB WiFi adapter or an ethernet cable if you care about using a web interface, compared to the more premium Ender or the next suggestion. It's at a very reasonable $220 USD, and is probably the way I'd go personally if I needed an upgrade https://www.elegoo.com/en-ca/products/elegoo-neptune-4-fdm-3d-printer The Bambu Labs A1 Mini is perhaps the closest thing to an "appliance-grade" 3D printer that you can get in this price range, with intuitive control from a web interface, lots of sensors for reliability, and the same 500 mm/s speed rating. It's a high-tech, high-feature machine that's ideal for someone who wants reliable, ready-to-go, 3D printing, and is willing to spend slightly more for a machine that doesn't really need or support tinkering. It's main downside compared to the other two is that it has a smaller build plate, but 180mm^3 is still plenty for Technic parts. This one also has an option for a super-cool multi-color add-on option, but that adds $160 and isn't really necessary for functional Technic parts. This one is right on $300. https://us.store.bambulab.com/products/a1-mini?variant=41513493627016 As far as what @Krzychups is saying about filament dryers, I'd say that they are important for some filaments, (like the nylon he mentioned, I believe), but aren't necessary for a lot of printing. I've primarily printed with easy-to-use PLA, which is strong enough for most Technic purposes, and doesn't require any kind of drying. I just keep mine in the open air, and the worst that happens is the occasional time filament will break, and that's usually when I'm moving stuff around on the printer, not when I'm printing. I've also used PETG (stronger) and TPU (rubbery) from time to time, and those I keep in sealed bags with desiccant packets, which has worked fine for me. Hope that helps!

Huh, that's an interesting thought! I know I have several faulty switches, but it was always just that one position of the switch didn't work at all, while the other position worked fine with both directions of current flowing through. I suppose it could be an odd switch issue, but given that most of my Servos have failed at some point, been taken apart, and convinced to work again at some point, I didn't think to look for problems in other areas! I could try to check that out, but now that the switch and servo have been thrown into my mixed electronics bin, it might be hard to tell which ones it was that were on the model Thanks for sharing!

Thanks! The hoses were a nightmare... I think I spent close to a week on them

@Salih, this doesn't answer your question, but are you aware of the CADA micro-motor? It's a cheap, mass-produced motor that has a similar use case, so perhaps it's something you could use instead? It's available here: https://decadastore.com/products/micro-motor-jv5043, or cheaper on AliExpress

Well, the idea is that the topic would be chosen randomly/revealed on the day it starts, so that people wouldn't know what to start building. If they already happened to have something built, that could make things easier, but it's not a judged contest, so I don't think it's something we need to worry about. Thanks for the ideas! That is roughly the idea I'm going for, but since I'm seeing it as a challenge rather than a contest, it might be fine to have a somewhat vaguer topic Well, I see what you mean, but I really didn't intend for it to be an evaluation at all--just a fun challenge for an individual, with the added fun of knowing you're doing it alongside other people. It's really not meant to be competitive! Perhaps the number of people willing to participate is limited, but we already have the official Eurobricks contests for a quality competitive contest that (almost) everyone can enter, so I think it's fine to run a small side event, even if only a few people can participate by its nature

I'd agree that that's probably the best way to implement that kind of sway bar with Lego parts, but I really doubt that Lego would build a function that depends on normal parts twisting. Even if it works perfectly, it seems to me that they always treat all non-specialty parts as if they were completely rigid, in theory. That idea using a driving ring to connect two axle connectors is one I've used on my Ram TRX MOC a while back, and I'd say it works well! I'm not sure it would be reliable enough for use in a Lego set, though, since it depends on having the sway bar in the right position for connecting, and bracing it might be hard with only legal techniques. (I think I might have used a short 4mm tube between the axle connectors, which Lego wouldn't do)

That's true! It doesn't seem worth it to just update the charge port, though, unless it's required by law. I've heard rumors that was going to be an EU requirement--is that true?

The Spike hubs are micro-B ports though, aren't they? If it truly was a USB-C one, it would have to be something new, I think

I just did some math, and found it to be about 1:13.3, based on tire size. Thanks for the frontpage! I think it could be improved a lot with some smoother parts for it to slide into, and using the newer pneumatic valves through drive from their axle holes would take out a lot of slack--I just didn't have enough of those to try it. I expect it could be controlled a lot more precisely with an RC pump, but I never did a whole lot of testing with my onboard pump. It'd be interesting to know, since it could have been a good option, but I've already taken the model apart, so it's too late now! Thanks! It does feel like a lot of complexity for what could be a relatively simple problem I'm quite pleased with the air bottle! It provides plenty of air, and didn't cost me anything to make, as opposed to using an expensive air compressor. Thanks! Glad to see you like the windshield wipers. One would think that old 2L ring should work for the diff lock, but all of the clutch gears from 2015 on, including these differentials, has a larger internal lip that doesn't allow the old 2L rings to engage with them. Thanks! It'll be interesting to see what you come up with!

I'm pretty sure he's using them for both steering and suspension, after taking a closer look

Wow, that's some serious attention to detail! It's clear that it was a bit of a passion project!

I wonder how credible that is! A pneumatic excavator would be cool, but the real headline would be that new battery! It could signal a pretty dramatic change from the current electrical system (Or not; who knows!). That Porsche is the same one that was claimed to be the "most powerful yet" or something like that, right? Those two rumors could fit together interestingly...

True, I guess it depends on how much you want to tune the suspension towards stability or articulation, and Lego could go either way

It seems that one of the most recurring things we see in wishlists on here is an RC Pneumatic backhoe, and the sheer complexity of backhoes has made them attractive to me for a while. It wasn't until @J159753 happened to suggest backhoes to me that I started thinking about the concept seriously, and got quite inspired! The model has ten separate RC channels, with five mechanical RC functions and nine separate RC pneumatic functions, so, as you would expect, some creative thinking was required to get this many pneumatic controls run off of only a few motors! First I'll discuss the pneumatic function-shifting module, since that's probably the most interesting, and then I'll get into the main presentation: So, for the function selection, I settled on this mechanism using three PU L-motors for smooth programmable control from a PU train remote via a custom PyBricks program. One motor ran the 6L worm screws here (Mine are black 3D-printed ones, because I haven't gotten my hands on original Lego ones yet). It then moves an assembly through four possible positions. Then, in each of those positions, two sliding worm gears can be activated to rotate a sliding fork to engage a valve, in a way similar to @Mr Jos's concept shared earlier, though my design does have a lot of major differences from his. The programming for this was rather challenging for me, but in the end it works fairly well, and is able to move extra-far to compensate for the backlash in the system. The system ended up being relatively compact, in my opinion, though still quite large. It's reliability was fairly decent, though sometimes the sliding parts would catch, and some more complicated tuning in the code could have improved it further. I'm quite happy with the concept, though! Also, it's worth noting that this only provides eight of the nine RC pneumatic functions in here; one is run separately off a traditional valve Functions: Pendular front suspension Pantograph windshield wiper Opening doors 4WD (PF L) 4WS (2x PF Servo w Switch) Auxiliary Compressor (PF M) Arm Traverse (PF M) Differential locks (PF M for valve; 2x small cylinders) Arm extension, "Extendahoe," (PF M) Pneumatic function selection (3X PU L) 4-speed Gearbox (PU L) Front Arm lift (2x large cylinders) Front bucket (2x long/skinny cylinders) Outriggers (2x medium cylinders) Arm rotation (2x medium cylinders) Arm lift (1x large cylinder) Arm articulation (1x large cylinder) Bucket motion (1x large cylinder) "Thumb" (1x medium cylinder) Aesthetics: The bodywork is quite simple, but I think it's refined-looking enough for my standards. I used the JCB 4CX as a rough template for the model, but didn't follow it too closely (For example, my wheelbase was forced to be considerably longer) I was also super happy to be able to route ten pneumatic hoses to the rear by hiding them inside the 5L liftarms in the rear mudguards! It was cool to be able to use the exact same tubes to support the mudguard and run the pneumatics. Pendular Suspension: Nothing fancy here, but my outline requires a heading for it Pantograph Windshield Wiper: This is probably the best picture I have of the most satisfying function on the model! It was kind of an afterthought, but it ended up working really nicely to move the wiper side-to-side on a 4-bar linkage made of some bar elements connected to Robot Claws via super short pieces of pneumatic hose. It was connected to a lever on the rear of the roof by an axle for easy control, and was very fun! See the video below to see how it works. Opening Doors: I made sure the doors could open 180 degrees to allow the operator to leave them open for fresh air in the summer! 4WD: The drive was done by a single PF L motor, and worked quite nicely! Four-Wheel Steering: When I saw that the JCB 4CX had 4WS in real-life, I knew I wanted to try doing it myself, for that extra bit of gratuitous complexity I enjoy adding! I used one PF Servo on each axle, and coupled them with a PF switch on the driver's right side, to allow for switching between 4WS, 2WS, and crab steering. Sadly, the rear Servo started malfunctioning during the build, and would only turn one direction in the end. It's probably fixable, but I didn't care to take apart the model to deal with it. Aux Compressor: So, knowing that space would be limited, and that huge quantities of air would be required, I made it my plan to primarily run the model off of compressed air stored in an external 2L bottle, filled with a bike pump. This worked quite nicely, simply attaching to a port on the side of the backhoe, and requiring a couple manual valves to be flipped to connect it to the system. However, I didn't want that to be my only source of air, since I wanted it to be capable of truly disconnected RC operation, so I included a basic single compressor system running ungeared from a PF M motor. It's not fast, but it does its job of allowing for true RC functioning. Arm Traverse: One goal with this model was to allow the arm to slide left and right, like a real one. Pneumatics seemed like a poor fit for this, so I chose to run it off of a couple more 3D printed copies of Lego's 6L worm screw. These parts worked quite nicely for it, but bracing the whole arm on a sliding assembly proved very challenging, and once I added all the pneumatic hoses required to run to the arm, the traverse's operation became rather unreliable and often needed help. Differential Locks: With the Yamaha's new 2L driving rings compatible with the new system, we can finally get a modern diff+lock into a nice, odd, 5-stud space, so I was happy to be able to make that fit here! I used a PF M-motor with a basic mechanism to run a ninth valve for this function, which just used one small cylinder per axle for two diff locks. Arm Extension: After seeing the "Extendahoe" feature on some real-world Case backhoes, I figured it should be part of any ultimate backhoe MOC I built, so I included it here, using a PF M motor running a framed rack via a worm gear with a safety clutch. Pneumatic Function Selection: (See above, just after the introduction section) 4-speed Gearbox: I always like putting supercar-style functions into other types of machinery, so I was happy to include a compact little 4-speed gearbox in this model! It's able to be very small thanks to both the 2L Yamaha driving rings and the way I was able to integrate it into the rear axle. Instead of using an extra set or two of gears to change the gear ratio between the two driving ring's shafts, I appropriated the 28T gear that was driving the differential, and then added two 8T gears to it, to get a 8:28 gear ratio between the shafts, and then 1:1 and 12:20 ratios between the two ends of the driving rings. It was super compact, and actually held up well enough in practice, despite the questionable 8T-8T gearing. One downside was that the natural shift order would be something like 1-3-2-4, but because I was shifting it with a PU L-motor, I was able to program it to shift in the proper order anyways. Miscellaneous Pneumatic Functionality: The eight pneumatic functions coming from the distribution module included the front arm and bucket, two joints in the rear arm, outriggers, rear arm rotation, and both a bucket and a "thumb" on the end of the rear arm. The rear bucket was a 3D-printed copy of the old, old 4700 bucket, since it seemed to be the one in the best scale for this model. Everything worked well, with the exception of the rear arm rotation, which was too powerful and tended to self-destruct because of the way the cylinders never reached the end of their strokes naturally. The RC valves didn't have the proper reaction time for fine control of any of the functions, which would have been a big downside for working in practice, though this could have been mitigated by using a smaller, on-demand compressor, rather than the big 2L air supply I was typically using. With my power supplies being a MouldKing 6.0 unit and a PU Technic hub, I ended up having this rather unique controller combination! Anyways, I was pleased with this model! It was challenging to control precisely, but it succeeded in my main goals of including an enormous amount of RC capability and having an interesting pneumatic function-splitting device! More images at: https://bricksafe.com/pages/2GodBDGlory/backhoe

I don't think it causes any problems in practice--even using axles as torsion bars for tracked vehicle suspension is commonly done in MOCs without damage. I think it'd just be a philosophical issue for TLG, though, since it requires twisting parts that theoretically aren't supposed to be twisted.

True, and if they don't want to make a new part for it, I imagine you could combine one of those with a pair of 1x2 half-beams and a 2L axle to make a slightly bulkier version of that idea

That'd work for me!