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@Mr Jos nice! I did skim through your GBC videos to look for a compressor but I didn't notice it. Good to hear that it's reliable and working in (what seems like) a good pressure range. I think I will give this a try.

That could work... From the Lego website: The LEGO® Technic™ Force Sensor measures pressures of up to 10 Newtons (~1kg) for accurate, repeatable results. From what I've seen, a maximum pressure of 2 bars seems adequate for a Lego compressor, so, if using a small cylinder to actuate the sensor, the maximum force it would exert would be: 2 bars * area of cylinder = 0.2N/mm² * pi*3mm² (assuming piston diameter of 6mm) = 5.65N On paper then, this is within the realm of possibility, and could be as simple as connecting a cylinder directly to a force sensor and getting accurate pressure readings! If anyone has the necessary parts to try this out that would be great. Otherwise, I think I'll be ordering a manometer, a small cylinder, and a force sensor :).

Has anyone built such a thing? All pressure switch designs I can find online are similar to this one by @mocbuild101 and use the old PF polarity switch, which hasn't been produced for 10 years now: I have been thinking that maybe a switch built using the current system could use a variable sensor and be fine-tuned, turning the pump on/off at whatever pressures are desired. Here's a quick proof of concept I made. I don't have a manometer or storage tank to properly test it but if somebody else did that would be great. It uses the pump speed itself to detect when the pressure has risen and turn off, then every 5 seconds does a short pump to check if the pressure has since dropped. Maybe this is too ambitious and something else should be used as the sensor... If anyone has designed something similar using current parts I would be interested to see it! Alternatively, feel free to improve on my concept or use this as a discussion topic.

@jamesaguilar there's definitely a sweet spot with the duty limit - for me 30 has worked (with speed 100). Putting it much higher has me worried too about damaging pieces. Of course, a well-built end-stop goes a long way :).

Enjoy! Many useful and interesting parts have been released in the past 20 years in the Technic theme. That would be great if you could make this work - it could open the door for (inverse kinematics for) 7dof robots the likes of which I haven't seen before in Lego...

Nice work fitting those functions in at such a small scale! This link just takes me back to this page...

Cool! What an epic and ambitious project. This could end up as the most advanced GBC ever . Thanks for sharing the updates.

Interesting... the new worm gear can be used as a helical gear, as demonstrated by Yoshihito Isogawa:

I think you are so close to making it work, and it would be so cool if you did. If you do decide to revisit it, I strongly suggest you watch this video (from 6:37 particularly). The principle shown in this video is almost fundamental to many of my creations now. If you built such axles into the main drivetrain of your machine, I think you'd be halfway to making it work. Then maybe some better pen holding method would be the finishing touch. If you leave it be, that's understandable. Either way, thank you for sharing such an interesting project despite it not being finished.

Thanks. I wonder why as well, but it hurts my head to think about. I suppose they probably designed this part with a more complicated (8 speed?) gearbox in mind, so I'm interested to see how that will look!

@allanp my only question is if the catches are hard coupled or not. It appears the answer could be yes, and they have axle holes on either side that are 45° out of alignment:

As @allanp mentioned, it appears that BCEFGH are neutral on the rotary catch while D is left and A is right (in this view). The two catches are 45° out of phase, which would make the 8 positions: AH = right/neutral BA = neutral/right CB = neutral/neutral DC = left/neutral ED = neutral/left FE = neutral/neutral GF = neutral/neutral HG = neutral/neutral However, it appears that the right hand catch cannot shift left as its connected driving ring is restricted by a blue liftarm. So, my guess is that the mechanism is somehow restricted to these positions: AH = right/neutral (3rd gear) BA = neutral/right (2nd gear) CB = neutral/neutral (Neutral gear) DC = left/neutral (1st gear) This would give a 3 speed gearbox, with neutral above 1st gear as on a real motorbike. What do you guys think?

@nico71 thank you very much for the response - very informative! I would love to see a radial engine

Superb! I particularly like the control panel. Would you say there is much efficiency difference between your switchless 'switches' and unmodified Lego switches?

Oh, I love this thread. Kevin Clague has some interesting contraptions:

Ah, many fond memories of the Mindstorms community back before YouTube and Eurobricks... https://web.archive.org/web/20030206014846/http://mindstorms.lego.com/eng/inventions/ Exactly! I see the Technic hub as basically a Mindstorms hub without the name - and for so much cheaper, which makes it accessible to more people. It is compatible with the Mindstorms sensors through Pybricks and hopefully now it will become compatible with them through the Powered Up app too. Goodbye Mindstorms .

I'm saddened by this news, but not entirely surprised. I can think of many reasons why this has happened but the first that comes to mind is that as Powered Up has entered the mainstream, and Mindstorms hasn't evolved dramatically, a situation has arisen where there's not much that Mindstorms can do that Powered Up can't. I don't see this as all bad - hopefully it's a step towards a more organised Lego electronics ecosystem.

I like it. Nice, snake-like movement.

Nice . And your ferris wheel is a thing of beauty. Looking forward to see it work.

Congrats!

I don't think so with the Mindstorms official (python) software and I see this as a huge limitation of the software. With Pybricks you can control as many motors in parallel as you want by setting wait=False as a parameter .

That makes sense. I'm making my own 6-axis robot and was hoping to just rely on the smart motors to detect end points, like I did with my plotter. Of course, the 3 infinite joints would need some kind of (temporary) stops for calibration. This is a good addition and I wish I had room for one (am using all 6 ports on the hub). By the way, this remote is really cool too. Honestly, I'd glanced over this topic before but am only really appreciating it now that I'm building my own robot. I'm 50/50 whether I'll use your differential method or program out the 'coupling' on my robot. Either way, it's an innovative method and you've documented it (and the rest of the robot) well for people to look at, so I think there are at least a few people out of the 4000 views of this topic (plus those on Rebrickable) who have gotten value from that .

Thank you for the detailed reply. It's very impressive that you managed to decouple the wrist joints AND the gripper. Oh my mistake, I was. I saw a comment from ~2 months ago and didn't realise you'd already released a new version. I see the usefulness of the 3D printed part for infinite gripper rotation and have also thought about mounting a Spike Essential hub and 2 small motors on the wrist of a robot. I think Pybricks might eventually support hub-to-hub communication which would be ideal for this - one Mindstorms/Prime hub on the base + one Essential hub on the wrist = 8 motors... perfect! Anyway, thank you for sharing detailed updates over time. It's so nice to follow and see the robot get better with every post!

@Glaysche Wow, I just read through this thread for the first time and inspected the studio model (thank you!) and this is quite the impressive machine you've made. Using differentials to decouple the joint movements is genius, and I imagine it saves a bit of pain when it comes to programming. What is the backlash like though, considering so many more gears are needed for it? I read on Rebrickable that you're working on a new version - looking forward to it! Do you plan to omit the 3D printed part and make it pure Lego?

As in I came across a certain GIF which would be an insane coincidence if it's not what you are replicating :P I won't mention it in case you want to keep it as a surprise for others.