Toastie

So LEGO hubs have principally comparable problems, right? It is worse with BuWizz, but essentally using a PUp L motor (tacho motor) as servo is not necessarily the best solution; it would have been much better to have real PUp servo motors, isn't it? Best, Thorsten

Oh, sorry, missed that. But this "not going back accurately to 90°" thing still does happen to some extent? Best, Thorsten

Ah - which could simply mean, that the hub missed some of the "clicks" from the motor when rotating. Phew, accurately getting each click is a rather tough task, particularly when so many clicks are coming in! Such errors easily build up; when the controller believes the motor is at the 90° (center) position, but it actually is not (caused by these missed pulses from the hall sensors and motor power was still delivered by the hub until it believes, the motor is at the 90° position) then the next steering command all the way to an end stop in the direction of previous error will certainly introduce the next error, because the motor is at a final hard stop, but the logic inside the hub is not ... This should result in some interesting behavior (OK, others find disastrous ). Well, don't use a tacho motor for a servo task - or use really fast and reliable electronics combined with smart software, when using a tacho as servo motor. So does this erroneous behavior happen with the LEGO hubs as well, when tacho motors serve as servos? Best, Thorsten

I watched that video again (as I don't have PF servos); at 0:54 you clearly see that 0°/90°/180° are hardware "coded" into the motor as the copper "trace" is cut at these positions. I also believe in seeing a potentiometer at 0:57 in the front part of the servo, lying in the little bowl. So this seems to be a classical DC servo motor, where the PWM signature is translated inside the motor's electronics to the corresponding power feed to the motor. A PUp L motor does not have all these "servo things" (dedicated electronics, no software), all the smart stuff has to be done with firmware/software, per PUp data communication motor <-> "hub" = controller. And I believe this is where things can definitely go wrong. The resolution of the encoder inside in PUp tacho motors is 1° = 360 clicks per full revolution = 180 clicks per half circle. This is a rather "fine grid" and calculations of the "error" between set point = position of the (software) dial and the actual position of the (calibrated) motor, are done by the hub's firmware. For a tacho motor (which is not primarily intended to function as a servo) calibration is of course necessary, because it does not know "where it is" when it is powered on, in contrast to a hardware servo, as it has the potentiometer telling it, where it is ... As far as I know, there is no hardware "zero" position, I may be wrong though. So yes, this erroneous behavior of the PUp L motor on the BuWizzes using servo mode seems to be a firmware/software problem. Best, Thorsten

Well, this seems to be a copper-type rail he is cleaning, providing continuity to other parts of the servo rather than providing a proportional response to the angle, as a potentiometer would. Oh, I just realized that this is a LEGO PF servo motor - there is zero intelligence in the PF receivers other than providing PWM signals from power levels 1 to 7, if I am not mistaken. So all the "work" is done inside the servo motor electronics. When you go to PoweredUp tacho motors, all you get is a signal back from the motor - and I believe it is clicks/rotation or something the hall sensors provide. From that info, the controller has to do all the (PWM control) work. So when the BuWizz glitches when using LEGO tacho motors like the PUp L motor, it appears to me that there is something wrong in the software/firmware of the controller. Again, I learned that the hard way, when I programmed PID control into the RCX. The 16/revolution resolution (hey, does that sound nice or what?) was sometimes causing some "spikes"; but moreover, the BuWizz has to do so many more things/second when running wild off-grid competitions, as a train requires. Just gussing here, others may know much more! Best, Thorsten

Hey, no problem!!! Asking tough questions like this one is a) rather refreshing to me and b) one of the more relevant reasons for the existence of an educated, well maintained forum that Eurobricks is. As I have hardly ever worked with servos, nor do I have a BuWizz and such, but believe in knowing their principle of operation of servos, I have multiple questions :D What is the feedback mechanism in the servo motor(s) used with the BuWizz device? Are these PUp tacho motors? These are not servo motors but rather motors delivering a digital signal back to a controller (e.g., BuWizz) mainly for PID rotation control (constant speed of the controlled axle) as well as pulse counting control for reaching exact stopping destinations, which is what you want to accomplish, right? When using the BuWizz in that "servo mode", does the motor rotate at constant rpm (no load) to the final destination, and then suddenly stops? Or does it do that smoothly? In other words, does it slowly accelerate, then rotates at constant rpm, then decelerates and stops at the final position? Again, with no load, just freely running. Now when using PUp motors, you have a fairly high resolution for one 360° rotation; the RCX rotation sensor had 16 steps per turn (https://www.philohome.com/sensors/legorot.htm) I believe PUp motors have a much better resolution; in this reference 1° (https://bricks.stackexchange.com/questions/16395/difference-between-the-simple-medium-linear-motor-45303-and-the-medium-line). You are absolutely right: The higher the rotation resolution, the better are the results. When the controller has to do many other things than paying attention to the numbers (clicks of the rotation sensor), then things go easily out of control. I have no clue, though, how much intelligence is inside the PUp motors in this regard. Do they just feed back pulses? Do they process the pulses? I believe @Philo knows so much more on these issues! We'll see, the forum has been summoned All the best, Thorsten

Yes, you are absolutely right - I simply thought "textbook" - in most examples, there is one wire split into branches with different resistances. Sorry for the confusion, and thank you for clearing that up! All the best, Thorsten

Well, sort of - in an ideal case, the current is the same in all cables. The problem with "older" or better, less conductive cables, is that they a) act as series resistors in the common line (reducing the voltage and thus current further down) and b) power dissipation in these is higher than in better conducting cables, as the generated electrical power is proportional to the resistance: P = I^2 R. Best, Thorsten

Essentially yes! Sort of, yes: The cables attached to each other in parallel, provided they have "good" contact pins (i.e., they are not significantly corroded, "Kontakt 60" spray is a good choice for cleaning them in addition to wiping them several times after spraying them), do represent one "wire pair" to which all the lamps are attached. The current flowing in this "wire pair" is what they need to handle. When adding one lamp, the current flowing through that lamp adds to the total current flowing in the entire wire pair (I), provided by the power supply. This additional current flowing through that added lamp is determined by its resistance R. The total resistance of all lamps decreases with each lamp added according to: 1/R(total) = 1/R(lamp 1) + 1/R(lamp 2) + ... 1/R(lamp n). The current flowing in such a circuit is I = U/R, where U is the voltage of the supply, in this case 12V. The units are Volt (V) for U, Amperes (A) for I, and Ohm for R. Example: Let us assume, the resistance of a lamp is 100 Ohm (which it is not, just for the sake of clarity). At U = 12V, the current flowing through that one lamp is I = U/R = 12V/100 Ohm = 0.12 A. Putting two lamps in parallel leads to = 1/R = 1/100 Ohm + 1/100 Ohm = 0.02 1/Ohm and this to R = 50 Ohm. So the current doubles: I = 12V/50 Ohm = 0.24 A. For three lamps you get R=33.3 Ohm and I = 0.36 A - so each lamp adds 0.12 A to the total current flowing. There is of course a limit (that I don't know, but could do some rough calculations) to having lamps in parallel on one power supply: a) how much current can the supply deliver and b) how much current can 12V LEGO cables handle before they get "warm". And these are all "ideal case" numbers, the reality may look a bit different, but in this case not that much. Best, Thorsten

Well, each lamp is directly (i.e. via the LEGO cable connection) connected to the transformer; this is usually called they are "connected in parallel". A serial connection would be when transformer output_1 would go to lamp_1_in, lamp_1_out would go to lamp_2_in and so forth and finally lamp_n_out would go to transformer output_2. See for example here: https://www.allaboutcircuits.com/textbook/direct-current/chpt-5/what-are-series-and-parallel-circuits/. You can replace the resistors used in these example with 12V Lego lamps and the battery used with 12V LEGO transformer. All the best, Thorsten

Was that your code or part of it they used? I hope so! All the best, Thorsten

You could ;) but what you want to do is "chaining" them in "parallel" For example only, like this: In principle, you can chain a lot of 12V light bricks that way - it all depends on the 12V P-supply's capability (= how many amperes it can deliver). And of course on the 12V cables (i.e. their resistance, but they are doing quite well in this regard). Just try it out! Best and good luck, Thorsten

Well, you know what? I don't care whether a random bot, a random AI (whoohoo), or simply Google randomly pops in here with an - as it appears - relevant question, at least to some here. I certainly don't learn anything from the OP's question - but I do from educated replies, discussions, ideas, fears, projections, conclusions - from the (I guess) human forum members. Whether an AI learns from this thread - so be it! Google essentially learns from every click I make. Do I care? No, I just use Google. Should they use me, well, that is the game, isn't it - nothing comes for free. And when it seems feasible, I use AI. Use as in: To my research group's benefit. I simply like to engage in discussions relevant to what is actually happening now or may (or not) happen in the future. On a "level" I don't find that often anywhere else in this virtual social world; others may do and also know better places. I don't. Well, I do happen to have other means for such discussions as well - in human worlds. In conclusion: Why should I want to wake up? This is a so conscious and well alert discussion of humans, thanks to the AI's question. Think about it ... Best, Thorsten

I have no clue what the ratio is, that may very well be; I believe "current" is the key word here. Me too - but again, there is a key word here: "soon". I don't care abut the time frame. AI is a "process" that has started some 70 years ago. Call it "hype" or whatever, disruptive processes always begin slowly, like exponential functions do. Here is what the "chief data officer for the LEGO Group" had to say about TLG and AI back in December 2022 (which is a long time ago in the data industry): "It [AI] could be about helping our molding machines work more effectively, or it could be about more effective customer engagement, or it could be about just creating fantastic online building experiences to help kids play together when they’re using the physical product." (Cited from that article referenced below) Here is the entire article, it is an interview style piece: https://www.mckinsey.com/capabilities/quantumblack/our-insights/how-lego-plays-with-data-an-interview-with-chief-data-officer-orlando-machado Best, Thorsten

Well ... True, but times change ;) It won't because it should not be allowed to do so ... It won't because it should not be allowed to do so. A lot of this stuff is already known to Stud.io. I carefully disagree here: Of course there will be tons of these designs. But I believe a LEGO designer will see that right away. The AI works essentially for free. Experienced LEGO designers are really expensive. The usual stuff, I know. But ... Now, why do people believe an AI algorithm, a program, will totally design the set? Box, art, instructions, no flimsiness, all legal connections, the whole bang? Not the point. Such an algorithm may come up with really cool "hulls" - well, "may", duh - just go to reddit or any other current so cool outlet ... Yes, there are soo many pictures but hey, maybe the entire - so educated human assessment process should kick in. "AI" is generally a computer program, and (at best), should be currently viewed as a tool. Back in the days, Word 5.5 form MS was called totally evil. As was Win1.0. Things apparently evolve. There seem to be some survivors and diehards still using MS Word on MS Windows platforms. Yeah, true, of course. But how about having experienced humans looking at all the trash? Define exorbitant - maybe your AI should not crank out trash all the time. Maybe a little office space with experienced designers should do the training. I really don't want to how many folks in the far East may do that ... and then imagine, the trash rate goes down. Programs only spew out model after model, when told to do that. No, I am sorry, LEGO bricks are real, their numbers of combinations are >absolutely< clear. They seem to be endless, but so is a PetaByte. And a trained AI is not a random piece of software, going into the wild. Training is one thing. Assessment of the results is so much more important. And yeah, algorithms can do that as well. Crunching through an existing, ultimately complex LEGO build is a joke for a suitably equipped AI machine. What it does, or we do, with the "analysis" (yielding another crazy dataset), and even what the analysis tells - I have no clue. But hell, this is what Google does every nanosecond ... It is all flowing as of now. That is my take. For me, the key thing is how we plan the interaction between "AI" and human's - well, let's call it - ingenuity. Best, Thorsten

Maybe some others do. We use it now and then in our research projects, works quite well from time to time. Certainly not always - does mostly make no sense at all using it - but there are sometimes such complex datasets, we experimentally recorded, that we simply do not have the slightest chance to "classically research" the meaning behind it. And yes, you may ask: "Why do you do such weird things in the first place? Make it simple, stupid." Good question, good advice, my answer would be: "We tried for more than 10 years narrowing down the experiments to lift the complexity - and failed." Does all this have anything to do with "creativity", "imagination", "talent", "research and development"? Surely for the latter - for the former I don't know, as I don't know how they "work". Best, Thorsten

That: "Years". And to further add: Can do "within the limitations of a profit oriented company". We are not talking about "freely experienced designers can do" approaches, are we? Furthermore: What are "years" in a lifespan of a human? Or a company's life? I have no doubts, >none<, that AI will change the "LEGO" world. Maybe in "years". Well, I believe it is actually happening right now. Maybe not in the TLG bubble, who knows, which was established (but apparently did not much change since then) more than 60 years ago. And then: What is wrong about such change? The fallout (as in "what do we 'get' from the gods") of new LEGO sets is certainly controlled by the anticipated extent of commercial success, isn't it? I mean, there is competition out there. When the application of AI leads to raking in more money, do we actually believe, TLG won't do it??? Well, just my 2 cents, essentially worth nothing! Best, Thorsten

Oh, it sure does depend on the parents! Very much. There are at least two pillars, this dependence or let's say support rests on, isn't it? Education and money. Same here in my family. Money has become far less of an issue as compared to when I was young: Back then, money was all the issue, always. My parents had no clue, none, what a TV set looked from the inside and computers were not invented back then as if they'd ever cared; they worked with their hands 12+ hours a day. ... certainly don't come for free, nor does the time you need to educate yourself using or teaching "them". Cool when you can walk into charity stores and chase these items, but it tells, doesn't it? That is what I feel, when I am browsing for such marvels in these stores - others go for cheap clothing. Yes, it does depend on the parents, but that was a bit of a shortcut, as far as I am concerned. I believe there is more (well, there always is ...) - there is oneself. With all you have, that comes for free. I know: Dream on, pal. But that is what drives me. Best, Thorsten

Nice!!! I really like very much, how you integrated the hub + these bulky motors (and yes, with all the power and intelligence of both!!!) into the Jeep's rather small frame! It certainly looks like the Wrangler and the electronics can do a lot! Best, Thorsten

Maxibig, da Guugel! Best, Thorsten

I so much love these positive replies, as in: "That is" or "That looks like" - so much more than "that's not LEGO" ... Thank you very much @Peppermint_M!!! Cool find! Huh? This is a very nice set! Have fun with it! All the best, Thorsten

Well, rather different approach here, I believe ... I am old, a total nerd, and a chemist. It does not get worse, I believe OK, so my daughters have grown up since long and live their lives, but they visit regularly, and we do spend some vacation time as a family. Now back in the days, there was (and still is) a table in the living room, set at about 90° angle to the TV - with no chance of watching TV - called the "Maltisch"; the girls used to be rather busy on that table. This is where I "build": Sometimes LEGO, way more times other stuff, such as vintage electronics, for example, my interfaces for 8bit wonders making them talking and listening to #9750. Mostly, though, I am thinking about making stuff. Have my notebook open (notebook as in collection of paper pages ;), and let the (often crazy) ideas flow in ... I love doing that. OK, I admit, mostly with one or two beers flowing in as well. What actually "plays" in the background is all music to me: Family laughing, watching "Germany's next top model", you know, these kinda things, I have difficulties to relate to, but love to be where all "others" are. The maximum "brutal action" allowed on the TV is "Columbo" (Yes, we really like that, the older, the better), my wife doesn't like any violent action at all. She also enjoys gardening shows a lot - and all that is lovely music to my ears. Tolerating each other's likes and loves - is wonderful music to me. All the best, Thorsten

Heehee - the box won't add anything other than having a ... box - you possibly wouldn't know where to put it - happened to me: I am now a proud owner of a TI99/4A box. And now what? The >content< of the box, a TI99/4A along with power supply and speech synthesizer, makes all the difference. The box is ... worn down. I'll put it into the recycle bin (and yes, I'll say a few words, when doing that, sure) - and then have fun with the real thing, a dream came true!!! So, I guess your wallet has suffered a bit, huh - but: As Donald Duck Dunn says in the Blues Brothers movie: "If the sh*t fits, wear it!" That's what I do, and I don't care much about what others think (about my sh*t). Have fun with all your 12V trains!!! All the best, Thorsten

Oh yes, this is really cool! Next level: How about "showing" some heart diseases or failures? For educational purposes, of course. That would be so cool! One example: They told me, that I suffer from a "left bundle branch block". First, I don't suffer and second, it is what it is - but your heart model may actually illustrate that - uhm - failure upon partial disassembly, right? So cool, I love it. Not only from the replication perspective, but much more so from the educational perspective. Best wishes, Thorsten

"Here we go again" ... thank you very much for your reply! Yeap, that is my route - use an ESP32 board, kick out the damned cell phone - along with all that LEGO application software called C+/-/apps, and kick in direct hub to ESP communication - with a little help from BLE remotes. Really nice! All the best, Thorsten