LabManager

Thanks. K1t is a BAV99S switching diode (https://assets.nexperia.com/documents/data-sheet/BAV99S.pdf), which is used a rectifier, so both LED's get turned on when current comes from the hub in any direction.

It's very interesting to see that the PCB was designed by LEGO in 2015, while the PUP lights (88005) were introduced only in 2018. Do you have a bigger picture of the board? Does the black 6-pin chip have any code on it ?

Does that mean that you've written some Arduino code to control PUP motors with an ESP32 ? I mean not only to power them, but also to read their sensors' data ? PUP has quite a sophisticated serial link which uses 2 out of 6 wires in the PUP plug. And while LEGO has opened it's wireless protocol for Bluetooth communication with modern Technic's hubs, the wired serial link with motors/sensors is not officially documented. As I have some interest in developing a DIY RC-controller for LEGO motors, the best materials I've found yet are 1) reverse engineering by Philo (link 1) 2) pybricks sources (link 2). I guess BuWizz developers also have a good understanding of that, but their firmware is not opensource.

Hello! I'm trying to use BrickController2 to control a Powered-up Train Hub (88009) with two attached PUP L-motors in a small RC vehicle (A motor for driving and B motor for steering). However, when I create a profile in BrickController2 and try to test it, the app can successfully connect to the hub, but the motors just don't react to the controls (even if I set their mode to the most simple NormalMotor). What am I doing wrong ? Some remarks: 1) The hub and the motors are operational, moreover, I've managed to control the L-motors (without steering of course) by connecting the hub to a train's remote (88010) 2) The same profile works just fine if I use it with a Technic Hub (88012)

If 60198 is really going to retire in December 2025, will this set become the one that was available for the longest time among Lego Trains ? Had they been selling any other Train set for more than 7 years ?

I'm expecting new train sets not earlier than 2026. At least, this date is more or less reasonable since first powered-up trains debuted in 2018, then there were two more sets in 2022, so I think the next ones may come in 2026. And what is interesting for me, the 2024's Lego catalog still features the 60198 Cargo Train from 2018, not the 2022's 60336 Freight Train! Can't understand why they still advertise the 60198 set which is out of stock now. Looking at new 2025 train sets, one can only find Duplo trains there. I've noticed there's a new purple action brick with a star on it, wondering what is the function of this new brick and if the old duplo trains will recognize it. The updated bridge and the new tunnel also look fresh. Overall, both me and my son still find Duplo trains more functional than the City trains Wish Powered Up trains will feature the same sensors and sounds some day - they could place the color sensor and the speaker inside the second smart-bogie under the train, and the Powered-Up serial link could be used to control the train's hub.

It's disappointing that TLG continues to use stickers instead of modelling headlights with trans-clear or at least white parts. In my opinion the way they did it in the initial 1:16 scale sets (the blue car from 42098 and the old 42093 Corvette) and even in 2022 (42138 Mustang) looked much better and it had the Technic's spirit then. The 2023 and 2024 1:16 cars started to use stickers, but they were smaller. Now this Corvette has a really big sticker and it will look totally incomplete if you prefer not to use stickers. What I like about this new Corvette is that it seems to be very challenging to make a motorized version, since it has a very low profile in the rear part.

Mine was from a local online store, it was packed in a branded MK retail box with M-0005 item code. Here are some pictures of it after disassembly. It looks very similar to the original Lego PF-motor (you can find a video with its disassembly here), at least there are contact pads that could probably work as a 15-position encoder. The PCB components are different, so MK servo is not a 100% copy. I could identify MX612 motor driver and a weird 14-pin chip without any marking on it. The next step could be to dump the firmware from that chip and make some reverse engineering to find what kind of signals it expects, but I'm not 100% sure that it has similar pinout to PIC and even if it was a PIC clone, I just don't have that hardware to read the chip (not mentioning it can also have read protection). So I just tried to control it with higher frequency signals (up to 2000 Hz), but I could not notice any difference in the way it works. It still rotates to a certain angle, proportional to the duty of C1/C2 signals, but it can't stop at that position and moves little bit around. Probably, as with original PF-Servo, there could be some magic numbers that identify the 15 fixed positions the servo can rotate to, and the signal's duty must match them exactly so the servo can work properly. Or, more likely, MK just cloned the hardware of the original servo, but couldn't (or didn't want to) develop similar signal/encoder processing inside the chip.

Sure, there are services which do PCB assembly (so called PCBA). However this is reasonable for mass production, or at least for small batch ordering. The other point is that PCBA is usually made with surface-mount technology (SMT), and this requires different PCB design using SMD components. In one word, this is too serious for a hobby project. So, unfortunately, for DIY purposes you really need to do some soldering yourself :) That's true. But ESP32-CAM is different, it doesn't include USB components to save some space and make the board smaller. Usually ESP32-CAM board is bundled with ESP32-CAM-MB (or you can order it separately), that second board is used for uploading. Here's a link to a tutorial.

Correct! Why would you want to connect a GeekServo to the BuWizz ? Buwizz 3.0 has PUP connectors so you can use PUP L-motor for steering.

ESP32 is a 3.3V chip, it needs 3.3V power supply and this is also the maximum voltage for input/output on its pins. ESP32-CAM board contains a tiny voltage regulator so the board can be powered either with 5V or 3.3V, but that does not change max voltage for pins. The buck converter and the voltage dividers do very different things. The buck converter handles the DC current up to 1A for the power supply, decreasing 9V from the hub (actually 7.4V since there's 2S LiPo battery inside MK Hub) to 5V for powering the ESP32 board. Converting 9V directly to board's native 3.3V is also possible, and that would be even more effective, but 5V power supply is also used for the GeekServo. @oracid has much more experience with these servos and suggests that direct 2S power supply is also acceptable for the GeekServo, but I prefer to follow electical limitations :) Resistors in the voltage divider are much more simple, they lower the signal level to 3V so it can be handled by ESP32 and they also limit the current which goes through the circuit (1+2 kOhm resistors take just around 2mA from the HUB, while C1/C2 pins can provide up to 500-800mA for a L-motor) There's a Servo class in Arduino's standard framework, but it supports only architectures for original Arduinos. For ESP32 boards, there's a different ESP32Servo library (but the class name is the same). Did you share this anywhere? If it was a kickstarter project, suppose there would be a lot of support! This is what I really looked for before starting my project! What you've done is really cool! As I see, you've mastered SMT assembly so the board is much smaller than mine. Personally, I'm not ready to do SMT assembly at home :)

@gyenesvi your understanding is correct. The PCB is used mostly for simplifying the wiring, and 4.8 mm holes are used to fix it on the vehicle (this is also an important function ) Everything else is done in the ESP32: with interrupts, read incoming PWM from pins connected to C1/C2, save LOW and HIGH timings in memory => calculate the rotation angle based on it => generate new signal for GeekServo (which is also PWM, but with completely different parameters). And this cycle is repeated continiously every 10 milliseconds. I don't think this can be done on a bare PCB with just basic electornic components, and some chip is needed anyway. I agree that the ESP32 is an overkill for a such trivial use case, and it could be implemented on some primitive chip like PIC, but that would require much more skills and knowledge than I have in electronics. Arduino is much easier to start with.

It’s been a while since I posted updates on this topic. Meanwhile, I think I’ve found the solution for most of my initial goals. These were the key features I wanted to have in my RC setup for LEGO: 1) Proportional steering (reason: it’s really needed to make a fast vehicle more controllable). 2) Using of PF-motors (reason: they are cheap and widely available). This goal is not fully met because I’ve chosen to use the GeekServo, but it is also cheap, and its quality is at least as good as 3rd party PF motors 3) Controlling the vehicle with a hardware gamepad without any kind of smartphone between the controller and the hub (reason: the less components, the better) And here is the list of the components I’m using now: 1) Mould King Power Module 4.0 is still the core component of my setup. This includes both the hub and the remote controller with proportional inputs. 2) Mould King Black L-Motor, which provides enough torque for a 1:16 car (however, I didn’t use it in the test vehicle for my demo videos, because they were shot indoors with limited space available) 3) The GeekServo for proportional steering 4) ESP32-CAM. It is not the smallest ESP32 board, but I thought it would be interesting to include realtime-FPV functionality. Can’t say this was a success, but it also works! 5) Custom PCB that acts as an adapter between MK hub and the GeekServo, implementing the logic which I described in the first post here. The PCB has 4.8mm holes so it can be fixed on a LEGO beam with 3/4 pins or axles. More detailed description, PCB files and Arduino sketches are available at my GitHub (https://github.com/pink0D/CameraBrick). I tried to use only commonly available components (even custom PCB’s can be also easily ordered nowadays), so I hope it will be possible to reproduce my work for anyone with basic soldering and programming skills. Some pictures of how it all looks like: And of course the videos: FPV demo GeekServo demo

Hi! What camera are you using for the FPV ? Can you share how you mount it on a such small car ?

If you don't mind controlling an RC car with your smartphone, than BuWizz 3.0 + PU L motor is the most straightforward way for doing that. You can also use a gamepad, but in this setup it is paired with the smartphone, which then transmits your inputs to the LEGO hub, so there will be some latency (didn't measure it, suppose it is no more than some additional 10-20 milliseconds). Another option is BrickController2 app, it works the same way, but supports not only BuWizz, but also LEGO original hubs. However, LEGO Technic Hub with 4 ports is very heavy and bulky, while Lego Powered-Up hub with 2 ports is smaller, but if you connect one motor for steering then your buggy is going to be very slow with just one remaining PU L motor.