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GroundskeeperWillie
Eurobricks Citizen
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Everything posted by GroundskeeperWillie
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GroundskeeperWillie replied to Coder Shah's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingSweet! -
GroundskeeperWillie replied to ninoguba's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingYes, but from watching the video it's pretty clear to me that he is not using pre-determined movements but rather set coordinates with calculated movements, probably using a model that knows the arm's geometry and limitations. But since he doesn't discuss how it's modelled and implemented it doesn't help much. I've been using the Java Mindstorms OS, LejOS quite a lot and it has great abstractions for many robotics tasks. But again, unfortunately, they are mostly aimed at controlling/pathfinding in 2D, not 3D. This is just to say that your suggestion to create an open source python project is probably the best way to go about it. Good luck! From a quick look, this looks promising. And you're right, doing this math from scratch is a monumental task. I've been a developer for 2 decades but since I've mostly been doing high level work, I still find robotics really difficult and I'm always struggling to find the right abstractions. But they already exist and it's just a question of finding those that match the problem at hand.
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GroundskeeperWillie replied to ninoguba's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingI can highly recommend watching this video from Akiyuki. Especially the second half has many details about its motion. Unfortunately it doesn't get much into programming details.
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GroundskeeperWillie replied to TechnicBrickPower's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingWhat a great idea combined with great explanations and the experiment to match. Wonderful!
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GroundskeeperWillie replied to WouterVessies's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingYou could use a rubber band in the transmission which will allow the motor to slip once it reaches the extreme positions. Then just use a timer than runs slightly longer than necessary. Then it will remain in sync without a rotation sensor. Alternatively, you could change the gearing of the rotation sensor to make it turn slower and thus increase the measurement precision. Let me re-phrase that. Making the rotation sensor turn slower will actually decrease the precision, but this is probably what you want. If it goes out of sync, it probably means it turns so fast that some ticks are skipped.
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GroundskeeperWillie replied to Parazels's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingThanks for sharing @MikeTwo9398.It's too bad about the lower capacity but it does seem to work fine nonetheless. I'll consider this for my Control+ and Mindstorms hubs as they are a little tame with 1.2V batteries in them.
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GroundskeeperWillie replied to Jundis's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingThat's a cute little tractor. Looks very authentic. Well done
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GroundskeeperWillie replied to Parazels's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingIt seems there are also 3.2V AA 14500 LiFePO4 rechargables. 3 of those come really close to 6 alkaline in voltage. Has anybody tried those?
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GroundskeeperWillie replied to seekersu's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingThere is an ongoing discussion on https://www.facebook.com/groups/PoweredUp/ about app-less control options. Doesn't look too difficult although it does require building a controller with custom electronics.
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GroundskeeperWillie replied to TechnicBrickPower's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
GroundskeeperWillie replied to pasquentmax's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingAwesome! Very well done.
GroundskeeperWillie replied to Coder Shah's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingDid anyone explore the possibility of bluetooth connectivity between the smarthub and NXT or EV3? It seems it should be possible, right? I'm kinda fond of using Lejos and its workflow but would of course like to be able to integrate the new stuff.
GroundskeeperWillie replied to nico71's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingGreat work! I can hardly imagine the work that must have gone into this marvelous machine. The programming mechanism reminds me of this "punch card" programmable crane from the 8888 ideas book, published in 1980:
GroundskeeperWillie replied to TechnicBrickPower's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingSweet!
GroundskeeperWillie replied to Carsten Svendsen's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingThis is an amazing build I have sometimes considered building a baler but have always given up fast because I could not find a way to cut features to avoid it getting too complex. It's incredible how you have just taken all features and the full complexity head on and solved it too! I'm gonna watch that video quite a few times
GroundskeeperWillie replied to TeamThrifty's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingThis looks great. Those tires are just what's needed for a Xerion. But please - we need a video showing off all those functions
GroundskeeperWillie replied to louisk's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingYeah, remember that thing. Was a fun build, even though I missed the right coloured parts and had to do a rainbow build. Worked well :-)
GroundskeeperWillie replied to PG52's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingVery well done, I like it a lot. Fine looks, clever steering and suspension and useful engagement of the PTO. The only thing that bugs me is that the hoist looks so massive with the mini LAs. But for this size that's almost impossible to do anything about. This is even a problem for the much larger 42054 Claas. Makes me wish for smaller LA's.
GroundskeeperWillie replied to imurvai's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingYes, that works. It gave me a hint to enable location permission. It is beyond me why that should matter but alas... And with location permission on, voila - both nRF, Brickcontroller and the BuWizz app work and can connect to my BuWizz 1! So, thanks for the pointer I'm looking forward to trying out BrickController but unfortunately it seems it can't connect to my cheap PS3 clone controller. Are there any tricks for making that work? That was the official app. Turns out there was an update I missed and the error is gone. It's an Android tablet but its away on vacation ;) I'll try it our when it gets back.
GroundskeeperWillie replied to imurvai's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingHi, I've tried Briccontroller 0.32 on my Nexus 6P but it can't find my Buwizz 1.0. The Buwizz app also can't find it (and now it just crashes as soon as it is started ). However, I can see the Buwizz in the Bluetooth settings. I can connect to the Buwizz using the Buwizz app on my tablet so the Buwizz itself seems ok. Any idea what's wrong?
GroundskeeperWillie replied to BrickbyBrickTechnic's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingThis looks great. Good work!
GroundskeeperWillie replied to imurvai's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingThis sounds great! I'll be happy to try it with my Buwizz v1's as soon as it is out in the Play store. I went through the user guide but I could not tell whether it's of any practical use without a bluetooth controller. Can you control a model just using the app or is a controller necessary?
GroundskeeperWillie replied to Hanso's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingIt will if there are, say, 5 motor rotations of slack in the gearing. Then, whenever the direction is turned, the first 5 rotations would not change the position. So whenever the direction is changed, 100 rotations would only move 95 rotations' worth. By moving first 110 you get to "position 105", then moving another 10 in the other direction you would end up at "position 100". Does it make sense? Of course, if you could measure the slack precisely, you could account for it directly when changing direction. The approach above should work without an exact measurement as long as the extra motion is larger than the slack.
GroundskeeperWillie replied to Hanso's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingHi Hans. My suggestion would not remove gear slack, but by always approaching a stop in the same direction, the revolution count would accurately determine the position regardless of gear slack. When moving "left" you would stop normally, after maybe 100 revolutions. When moving "right" you would move too far (maybe 110 revolutions) and then a little left (10 revolutions) and stop. Then any slack will not affect the position (as long as no gear skipping occur). Of course, a sensor based solution is more fancy. The jerky motion looks like the motor is being stressed. If that is the case, it could be fixed by lower gearing or a more powerful motor.
GroundskeeperWillie replied to Hanso's post in a topic in LEGO Technic, Mindstorms, Model Team and Scale ModelingLooks great! Regarding horizontal positioning, the motion appears a bit jerky. Maybe that's why it is sometimes off. I'd say that given the gearing, using number of rotations should provide adequate positioning. An improvement might be to always overshoot and move a little back when moving in one direction. That should eliminate gear slack.
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