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About GroundskeeperWillie
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Technic
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Denmark
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Recent Profile Visitors
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Boost Invader building instructions
GroundskeeperWillie replied to Coder Shah's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Sweet! -
Reverse Kinematics and Path Planning
GroundskeeperWillie replied to ninoguba's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Yes, 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.- 27 replies
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- robot arm
- mindstorms
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Reverse Kinematics and Path Planning
GroundskeeperWillie replied to ninoguba's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
I 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.- 27 replies
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- robot arm
- mindstorms
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Torque and power - some insights
GroundskeeperWillie replied to TechnicBrickPower's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
What a great idea combined with great explanations and the experiment to match. Wonderful! -
LEGO railway crossing 4539 automated with Mindstorms RCX
GroundskeeperWillie replied to WouterVessies's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
You 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. -
Do you use 1.2V or 1.5V batteries?
GroundskeeperWillie replied to Parazels's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Thanks 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. -
[MOC] Old little tractor RS09
GroundskeeperWillie replied to Jundis's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
That's a cute little tractor. Looks very authentic. Well done -
Do you use 1.2V or 1.5V batteries?
GroundskeeperWillie replied to Parazels's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
It 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? -
About powered up compatibility
GroundskeeperWillie replied to seekersu's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
There 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. -
Mathematical Analysis of a two degrees of freedom differential system
GroundskeeperWillie replied to TechnicBrickPower's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
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GroundskeeperWillie started following Understanding LEGO 4-speed sequential gearboxes, 2020 Mindstorms set, Pybricks: alternative firmware for Powered Up device and and 1 other
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Grass seeding robot Lego mindstorms EV3
GroundskeeperWillie replied to pasquentmax's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Awesome! Very well done. -
2020 Mindstorms set
GroundskeeperWillie replied to Coder Shah's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Did 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. -
Nico71's Creations
GroundskeeperWillie replied to nico71's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Great 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: -
PI Day Gearing Ratio MOC using two differentials
GroundskeeperWillie replied to TechnicBrickPower's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
Sweet! -
[MOC] Kverneland FastBale - Non stop Haybaler
GroundskeeperWillie replied to Carsten Svendsen's topic in LEGO Technic, Mindstorms, Model Team and Scale Modeling
This 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- 10 replies
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- hay
- agriculture
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