gyenesvi

I did not mean gears, I meant the forks. Moving gears can be an option as well, but in many cases keeping gears centered makes things simpler.

Looks nice and simple, though for proper RC operation, it would require supports in the middle as well, which would make it not fit into 11 long frames. Also, the standard version is quite a bit high for not too big MOCs. I wonder if a more flat design would be possible by moving the forks to the sides, one to left, one to right..

Thanks for the info, indeed I could look this up and starting to understand more. I meant that question about the microcontroller board of @tseary, not the ESP32-CAM board, that one seems easier as it has more connectors. No problem, no rush and thanks for the quick answers. Having looked into it, it seems that it's even possible to make such things programmable after being soldered with some suitable pinouts and microcontroller programming boards. Really curious how far this could be pushed.

I have been looking at the code you uploaded and kind of understand what it does. However, there are some details about the making of the hardware and the programming that I don't understand yet, so some further info would be appreciated. First, the making of the board. If I understand correctly you had the the naked board made by an online service and soldered all the components onto it manually (or are there some components that are pre-soldered?), and you have chosen each component to your needs, the main ones being the microcontroller and the buck converter, which you can just buy directly from the manufacturer and look at its docs for the pinout diagram, right? So far so good. Though I wonder if there is an online service which also pre-solders such common components onto a board if you'd like them to? Second the programming of the board. I see it uses Arduino programming. Typically, Arduino boards have a small USB connector to upload the program to the microcontroller. What I don't get is how you program the microcontroller in this one? Is there some special development board needed that you can plug the microcontroller into and use for uploading programs to the microcontroller before soldering it in? And if so, is it the case that the program cannot be changed after it has been soldered in?

That's it thanks! It looks good on the right side of the image, and the angle also looks good enough. I'm a little worried that on the left side the edge would touch at some angle, but can image also that it just clears, have you checked that?

@aFrInaTi0n not exactly, I meant the same angle as the first photo just the wheel (axle) turned 90 degrees (as if the wheel was spinning) so that the other edge of the joint gets close to the pinhole.

Because a GeekServo is smaller, stronger, faster and more precise and have outputs on both ends :) And above all that they are cheaper as well, but that is not the most important advantage for me. PUP L motors also know their absolute position, but it's not marked on the outside, so it is a bit more difficult in that respect as well.

Actually that does not look as bad as I expected :) If you turn the U-joint 90 degrees can it still pass without tuching? That's the bottleneck I guess

Thanks, that sounds interesting! I was wondering if this board already contains a 5V downregulation of the signal which is supposed to be 9V or even higher in case of being powered from a buwizz? As for shrinkage, I think it would be possible to get rid of the pinholes (or keep at most 1) because a smaller unit does not need that much fixing, and in a housing, it could even just float in the air as well. Or a housing could have inverse studs on it just like in case of a PF plug.

Thanks for the explanation, so basically when using the C1/C2 to power PF motors you need the 500-800mA current, because it directly powers the motor, but when you use the signals to control the servo you don't need much current since that's only a control signal, the servo gets the power on another line, so this is why using the resistors makes sense there, right? Wow, that tiny board looks really awesome, this is almost what I was thinking. For me it would be enough to have a board that does not have an IR receiver, just the servo controller. For example, that way I could connect the servo to a Technic hub or a Buwizz unit, which does the communication for me already. I agree this would be a popular thing if published. The current form factor seems like 5x3 studs, right? How much of that space is used by the IR receiver, how smaller could that be if it only had the servo controller? Interesting to know that it could be done in theory (unfortunately I don't have enough electronics knowledge to understand those details at the moment). But if the microcontroller way results in a smaller and less problematic, than it's not worth it (and I might understand that better as a software engineer). So I'm curious about how the microcontroller path could be optimized!? If that little board could be shrunk a bit without an IR receiver for example to a 3x3 form factor, and put into some simple 3d printed housing to feel less naked, that would already be great!

Thanks for the answers! Indeed, that's also important :) This clarifies things, initially I thought it differently, I mixed the resistors up with something that does some signal processing of the two control signals; but now I understand that it just lowers the signals and passes both of them to the board. One thing is not clear though about the voltage divider. On one hand you have the buck converter to provide 5V signal to the ESP, and on the other hand the control signals are also transformed by the voltage divider for the same reason, because the ESP32 cannot handle 9V. So what's the difference between the two, why are two different techniques required to down-regulate the 9V signals? Is it that the power needs to be regulated precisely to 5V and for that you need a voltage regulator, but for the control signals it is enough just to lower them to some arbitrary low enough value that the board can handle? I also looked at your code and now understand that the analog control signals first get converted to duty cycle values, and then the output PWM signal for the servo is generated. I guess the Servo class which does the actual signal generation (write PWM signal with specified microseconds of frequency) is a system class on the ESP32, right? Sure, I understand that Arduino programming is much easier :) I just wanted to understand what would be required. The reason I think this should be doable electronically, is that a hobby RC receiver should have a similar circuitry if I am not mistaken. Such a receiver gets a 5V signal and GND and also receives some digitally represented control signal from the transmitter, and generates the appropriate PWM signal in its pins. Maybe in that case the task is one step simpler since the control signal is probably not analog but already digitally received from the transmitter, but the PWM signal needs to be generated. At least that is what I would guess, but I have little knowledge in electronics. So if anyone has more input on this, I'm all ears :)

Nice little experimental model, good start for the competition :) I like the construction of the half axles. It is weird that the two PF XL motors overheated with a 28:12 up-gearing and planetaries, that is similar to the up-gearing in 42099 with weaker motors, and many other builds employed such or even more aggressive up-gearing I think. Or maybe you were pushing it 10 minutes non-stop?

@LabManager, this is really amazing! I have always wondered how it would be possible to convert the PF signal to a proper servo signal. You seem to be the guy to understand it, so hopefully you can explain to me some further details that I still unclear to me. What I don't clearly understand is what are the roles of the custom PCB and the ESP32. As far as I understand, what the custom PCB does, apart from simplifying the wiring, is that it takes the C1 and C2 PF signals and that comparator thingy generates one signal out of the two? And then the ESP32 takes that one signal and maps that into the PWM signal required for the servo? For that you had to program the ESP32 to do the right thing, but the ESP32 has a PWM signal generator built in, right? What I have really been wondering though, is whether all this could be done with existing electronics components, without using an ESP32, just a custom PCB with the right components, such as a PWM signal generator. Does such an electronics component exist at all? Would it be possible to make a PCB that does just that without the need for programming it?

That's interesting!

That would be neat, but I don't think anything bigger would fit into the 3x3 space. I think even a 22T gear would touch the limits, but not sure.

If so then why are other themes adding new (even technic) parts and recolors like crazy? Some of them never used in the technic line. They are even adding technic parts that could have been very useful if actual technic usages would have also been considered. Just a few recent examples: Some more buildable/reusable towball arm would have been more useful. Would have been more useful with 2L pin instead of that long bar that sits there uselessly. Not bad, but expected this with 2L axle first, maybe more usages for that variant. Recolored for a botanical set where it's hardly visible, but not for multiple recent green technic sets..? Such a part would have never been recolored for a technic set I guess. Especially not to a color that is very similar to the only existing color (yellow). I don't even understand how this got recolored, even the yellow would have looked okay in that star wars set.. These examples just tell me that 1) the addition of new parts is not really a big issue, 2) they don't really try hard to bring the maximum out of the part selection. I guess they have some part quotas to limit new ones, but they don't really try to think systematically or negotiate across themes. Yeah, I understand that and agree with it unfortunately. Actually, the most practical ones missing are only the 4L and the 6L, not too many parts. Bricks are quite different in my opinion, because in system builds, it is much easier to join bricks to form longer parts. Bricks are meant to be stacked with overlaps and also they are designed visually to form a continuous looking surface. These are not true for liftarms though. Even though I wished for many lengths of links in this thread, in practise, introducing just the 5L and the 7L would go a long way already, exactly because we can almost build 5L and 7L suspensions, all other parts are available (towball arms, driveshafts), except the steering links. In fact, if I had to bet, I would have thought the 5L to appear sooner than the perpendicular version of the 6L.

Well, I just explained why I think it would be beneficial for them cost-wise. I don't agree with this for two reasons. For one, I'm talking about basic structural parts. Even if all those would be covered, there would be tons of other opportunities to release new interesting functional and aesthetic parts and keep AFOLs excited. Second, such AFOLs who keep track of the part selection and are longing for new ones are a very small minority. Most people who buy lego have no clue about what parts exist and are not collecting parts. They are collecting sets. They don't really care what new parts the sets contain, they mostly care about how it looks or what it models. Of course we've all heard about this and this is exactly what I was referring to. But it should not apply here. Again, exactly for the reason that I'm not talking about specialized on-off parts, but about basic, generic, reusable ones. But I think this past problem and the resulting policy has its (adverse) effect today. If this is the case then it should be revised, because I believe it is now hurting more than it is helping. I brought this specific example, because I think even using a recolor of the thin ones would look a bit messy (though better that the original), because you'd need to stack 8 of them into the door construction I showed above. I agree it is practically unnoticeable in the McLaren, mainly because there the suspension arms are almost horizontal and the suspension travel is minimal, in which case it does not cause toe in/out. It would manifest itself in a longer travel off-road suspension. But if the idea was to make parts that can be used in other circumstances as well, then an expensive supercar set would have been the perfect place to introduce that new part that would be required in other places to accompany that suspension arm. I wonder if they will use the suspension arms in something off-road, and whether they will introduce the 7L link, or just go with incorrect geometry again. That happened in case of the Ford Raptor. For that they did not introduce the 5L link and it was possible to feel the toe out when plying with the model. My problem is that there are only a handful of official models every 2-3 years that could introduce these new suspension parts, and they keep missing these opportunities.

Yeah, that was so far my best idea too, but I'm not into PCB design either.. Actually, I think space would be tight for cables as well, so I was wondering whether it would be possible to make it just using those needle-like thingies soldered to the PCB in the right places and then just connecting the different components (ESC and receiver) through those needles. I guess that would minimize space requirement and simplify assembly as well. Also, things like turn on button and status LED should be soldered to the PCB at the right place. But not sure if such a PCB can be made with an online PCB manufacturing service. Anybody with such experience / knowledge?

I like the direction, I have also been thinking of buying some chinese battery box (like this) and repopulating it with RC electronics inside. However, it would be great to go one step further in reducing the cabling, and to reuse some of those PF ports, charging port, and the turn on button already in the housing. Any ideas for how such things could be wired in? Unfortunately, I think in those chinese battery boxes, everything sits on a PCB that holds the motor controllers as well, that we'd like to replace..

Exactly.. The more I see about release of new parts, the less I buy this argument; it always felt somewhat arbitrary to me. I don't think it's about economics calculations, maybe some rigid old principles, and a huge amount of shortsightedness. I think a good sense of economics would dictate that the most economic way of managing a range of parts for a building system on the long run (and well TLG is there for the long run) is to have them systematically cover the base cases. Because such systematicity leads to simplicity in building and design, and simplicity leads to efficiency and ultimately, low cost. A key thing here is NEED, and how it's defined. In some sense, nothing is needed, if you don't want to build all the things that are not possible today. TLG could just keep pumping out sets built from the current part selection for the next 10 years, it would work in a sense. However, many parts would be useful. So I think it's better to think about whether the utility of a part would outweigh its cost. And I think, that may have the wrong perception within TLG. For one, the cost of making moulds for such ubiquitous parts like liftarms would amortize very fast, as they would be used everywhere (sure there are other costs of managing all the part selection but that's what TLG is really good at seen by the amount of parts coming out in other themes). For two, I think TLG really underestimates the cost of working things around. It cannot easily be measured in material cost, but in engineering hours spent on designing things that are hard to build because of the non-existance of simple parts that would lead to obviously simple solutions (I think the cost of working things around is often underestimated in many companies, because the management hardly sees how much extra effort the engineers spend on fixing problems that should not have come up in the first place with proper foresight). Also, there is the cost of the extra parts in sets that are only there because of the added complexity of the workaround itself. As for the concrete examples of 4L and 6L liftarms, here are my latest ones that came up recently (but they came up many more times). There's this new suspension part that I thought I'd try to build something with Only problem is that it is 7L, and TLG forgot to put a new 7L steering link into that super expensive supercar set, because, well, it's not needed, it can be sold with incorrect steering geometry as well, people won't notice anyway. So I thought, well, we have 9L steering links, so I could try to build a 9L suspension arm out of it, it has two pinholes in the ends that can be used for extending it with 2 studs, that would require a.. right.. 4L liftarm. Great :) The 4x2 L shaped version does not work here because the L shape is in the way for the suspension itself, and the 4L thin liftarm has axle holes in the end which would prevent the suspension arm to rotate in many situations because the most useful connectors to fix it have axle holes. So two obvious simple usages (for 7L and 9L) are out, and we can start finding ways to hack things around to make this new part really useful. For the 6L, here's an example that I made a few weeks ago about the G-class. The rear doors are just a big cluttered mess, and with a couple of 6L liftarms, it could have been easily improved a lot (the 5L flip-flop could have also been useful but not that necessary for looks as it is covered by the black stripe anyway). Right is the official, left is the improved. Sure, agin, it's not really necessary, people are already used to cluttered looks of lego cars anyways..

Holy crap, that’s a bunch of very useful novel parts! So many things I’m missing and would make much sense!

Wow, those are pretty expensive stuff! I understand that, but that does not make the geometry correct, the pivot points are still shifted (suspension pivot vs drive axle pivot). Can you please investigate this when you review it? Especially for high angles of the suspension. I wonder if length difference becomes noticeable / problematic.

This is genius, once I looked at these kind of walking mechanisms but did not find this really simple implementation, and so cool that it even has a cool shaping / details. Thanks for the instructions!

Somehow I completely missed this topic, probably I was on vacation in the middle of the summer :) Cool build, I like the use of 3 GeekServos for different purposes, it really shows their potential, and the diff locking system. It's a pity though that it takes up a lot of space and the drive motor and battery had to be pushed up so high. The use of the brushless motor with the planetary reduction is quite interesting though :) And the shape / body is nice too!

Thanks! About the front wheel overdrive, often used in RC crawlers, the idea is that for crawling, it is better if the car tries to pull itself up instead of pushing itself, because then it's less likely to flip itself over. Also, if it catches a ledge with the front wheels, those have more grip than the rear ones, especially if the car is at a pretty steep angle. At this point I don't know if that actually makes a difference in lego because it might not have enough weight / tire grip, but it was a simple but interesting challenge to make it. I think the stacking would not be a real problem, because the L motors can be geared together really easily due to their possible distance, in a way it is even an advantage that the gearing can be adjusted. Actually, I find that stacking the buggy motor format to the same axle is more problematic, because it wastes a lot of space and results in half stud gaps. As for cooling, I wonder if that's actually required that much. I haven't had any problems with overheating so far, I mean I never felt the motors would heat up, and maybe the more down-gearing due to the planetary gears help with that, as the motor has more torque with less struggle? I don't know the physics of that. But this is with a totally enclosed motor housing, and some cooling gaps could definitely be added as on the buggy motor, no? Or would that make it structurally weaker? Thanks, thought you'd like it for that reason :) Thank you! Indeed, I realized that even XT30 connectors take up a lot of space because they don't allow the cables to bend in their immediate neighborhood. And actually the first connector on my cables picture above does exactly that, one end plugs directly to the ESC and the other is the PF port. But I did the other ones to be able to split the cable to two PF ports. Did you have a solution for that, like soldering two PF connectors onto the same output? Or did you just stack multiple motors on one PF port? I'm not sure if it could handle that, I've heard some people melting the plug with 2 buggy motors..