DrJB

I've personally been exposed to the Mindstorms 'theme' a long time back, officially with the RCX 2.0, but also a bit before that during a course/project at MIT, which developed the predecessor to the smart brick. Fast Forward 15-20 years, I took part in a FLL event few weeks back and while it is always exciting to see kids invent and perform, it is a bit 'disappointing' that the hardware/software was not used to its full potential. For example, to complete some of the missions, the kids could have very well used some sort of proximity sensors or line tracking (the markings on the mat are for a reason). However, many of them resorted to simple 'open-loop' approaches where the left/right motors were given specific inputs/speeds to go around a given curve. Some of this can be blamed on credited to the coaches, but that's a different story. Of course, one cannot expect young kids (middle school) to understand yet let alone apply concepts of closed-loop feedback with PID control and the like. But nonetheless, such capability IS there, and the smart brick is REALLY smart. In fact, while at MIT, a greater emphasis was put on feedback control as otherwise, the robot would simply be another fancy RC toy. Now, all of this 'prelude' is to ask the community to share whatever contraptions they've come across that DO USE feedback control (or smart use of sensors' readings, besides motors' rotation angles). To me, the 'best' examples I have seen so far are: 1. Line following, a classic topic, seen in every released version of mindstorms (RCX/NXT/EV3) 2. Balancing bot (inverted pendulum) released in the EV3 Educational Version. So, what can you add to the list?

One possible upgrade: Gyroscopic Stabilization.

Neither the 8043 nor the 42009 uses the 16L axles ... I'm confused :(

I rarely comment on MOCs but this one is sure a beauty. The attention to detail, and reproduction of main working functions is very commendable. I like how you used parts from many themes (old vs new technic, old gray vs. bluish gray, ...) to fulfill all the functions and looks. All you need now is a harvester to complete an agricultural trio masterpiece. Thank you for sharing.

These were first introduced with the Unimog, for the so-called 'portal' axles. The goal there was precisely to increase the ground clearance (distance between ground and truck's underside). They seem like they do not do much, but you can install a gear reduction AND a spindle (below) for a wheel (wheel hub connects to spindle). +

You need to flip one of the differentials.

The elliptical mechanism (and the SW figure) is a fun contraption. Thank You for sharing.

It's a tough call, as to what challenge to put him up to next. From my experience, pushing those complex sets onto younger kids, while bolsters their self-esteem, might cause the interest to disappear soon. I had my son do challenging Technic builds as well at an early age. Now he's not interested in Lego anymore. So, tread 'carefully'.

Go for 8043, without any doubt. That set is slowly becoming rare (and expensive). Plus, the number of functions (playability) are second to none (well, except 8455).

Reminds me of the one on display at the UN building in New York. If I recall, the change of orbit is due to the earth's rotation i.e., Coriolis force. Hence the question: How much time it takes to go through a full cycle?

never seen any Technic sets on costco.com ... only City. :(

With all the anticipation for the $300 Porsche and longest speculation/critique thread ever (what a polarizing set that was !), I somehow took a break from Lego and have not bought any of the newer sets. In fact, my last set was the Mercedes Truck. Yes, I took my time and explored other hobbies such as Arduino, Raspberry PI, and lately the DJI drones. In all honesty, I do not miss Lego as much as I thought I would, except perhaps for the curved gear racks of the BWE and BlackBird's unrelenting dedication to Akiyuki's GBCs. To you all: Yes there is a whole world out there beyond Lego Technic and TLG. And yet, not with any remorse, I find myself wondering what is it I might have missed. Yes, I watched Sariel's reviews of the 2017 H1 sets and that ubiquitous white/printed 3L liftarm for the 40th anniversary. Is that it, anything with more substance than that?

My son took part in his school's FLL, and we attended the competition about 10 days ago. It was a good experience for him, but to me it left a bit of a bitter taste as their coach did not offer too much 'coaching' and was more like 'hands-off' (She had her own issues/priorities but I'll pass). I discussed this very topic with one of the judges and she said: Well, if you want to fix it, why don't you take an active part? ... and offered me to be a 'judge' for the rest of the year (still debating as am not sure of the time commitment). All in all, it was our first time and I learned a lot about the competition, scoring system and everything else beyond the actual robot and contraptions. What I also learned is that there are many requirements for a team to excel, and many of those go beyond what a single individual can offer. But, then again, the motto of FLL is NOT about winning, it's about working in teams ... i.e. Gracious Professionalism and Coopertition.

Very interesting indeed and for sure would love to see more 'integration' of Arduino/RaspberryPi/Lego. I, myself, have made the switch/jump to the two platforms and those 'teach' real life programming skills. In all honesty, I find programming for Arduino/RPI way more 'intuitive/rewarding' than doing a block-diagram with Mindstorms. Now, not sure how the Arduino/RPI platforms will compete/co-exist with the Mindstorms, though an Arduino/RPI is way more affordable. If anything at all, maybe TLG will see the benefits of developing this option seriously (Arduino/RPI), rather than their own language/platform/hardware ... etc. Good Luck with the project :)

Your best bet here is to study Akiyuki's and Philo's various mechanisms and learn from them. Keep in mind that the original GBC Specification states that balls are to travel at the rate of one ball per second. This is done to ensure no modules are starved while others have a huge backlog of balls. Again, the best way to learn is to watch 'attentively' what others have built.

I was is New York a couple of weeks ago and paid a visit the Lego Store near Rockefeller Plaza ... To my surprize, their prices are HIGHER than the official Lego MSRP. Granted, they had all/most of the latest/largest Technic sets on display (Porsche/BWE) but they were easily $20/$30 more than the list price. I asked one of the sales people and of course, he could not explain the disconnect. I wonder if they do that to offset the rent of the store ... prime location as they say.

If I recall, eBay now charges a listing fee whether or not the item sells ... Wonder how much that was.

One aspect we might have overlooked ... Doesn't eBay charge a 'listing' fee proportional to the 'Buy It Now' Price ? Though, for a publicity/advertisement stunt, that's a rather expensive one. ... unless the seller put few extra zeros, inadvertently.

Watch out for DBG technic parts with brown stains .... for sale on eBay. If you can't pass up the deal, they must sanitized!

9 pages and not a single picture??? Speculation (and wishful thinking) has become the rule-of-the-land in this forum

I've been wanting to setup a dedicated home computer for my EV3/NXT bricks, and with the cheap (and small foot-print) RPI, this sounds very appealing. Now, after some googling I found ev3dev but my understanding is that it's a whole different development environment. I ultimately want the same EV3 environment as that on a windows machine. Anyone knows how to achieve this or if anything is in the works?

Except that in Bricklink, the parts' IDs for flex axles are NOT the same ...

That is why, if you buy old sets from eBay, the first thing you need to do is sanitize/disinfect/wash thoroughly .... :)

Try to look up a thread I started a while back, called 'nails & glue'. I came up with a similar conclusion that, if you add all pins, and bushings, the number is sometimes higher than 1/3 rd.

Glad you found a solution to the issue you identified earlier. People in Robotics would tell you that the initial mechanism was not valid because it has a singularity in its Jacobian Matrix ... If I recall correctly, I think Akiyuki used gears to link the motions of the various axles, though I can't locate the video now.