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Feel free to share. Most of the missions are really easy to achieve with any robot design, and this bot is a demonstration of that ease. There are several other videos of other FLL challenges on my page here, as well as other Lego toys. I'm going to use this robot in a class of second and third graders I'm teaching this semester, since I have everything still together.

@@hydrogenhead amazing! im sure they are gonna love it.

Thanks. With more engineering it might be possible to reduce the number of runs, but the key to using this approach in competition would be a well-rehearsed team to minimize transition times.

I've been coaching FLL teams for over a decade, and use pieces from the old field kits to build demonstration models for the kids.

@@hydrogenhead That's awesome! I love to hear stuff like this, when I was a kid I was stumbling around in the dark with Mindstorms pre-internet 😅

Most motors are mounted rigidly in place. This motor is only physically attached to the bot at the axle, so any time power is reversed, the first thing the motor does is to swing between the two stops.

@@hydrogenhead ah I see thats brilliant well done

Thanks. At the start of the City Shaper season (and every season) I did an analysis of which missions could be achieved in a straight-line, which could be done in an arc, and which required a more maneuverable machine. When it occurred to me that it was possible to tackle all with a straight-line robot, I was hooked.

@@hydrogenhead well yes, and while it is an impressive feat, after city shaper, the game mats seem to have changes into models with more narrowed paths specifically for thinner robots (like a certain Spike Prime or Robot Inventor that appeared recently). Point is, i would love to see you come up with the passive actuator solutions in your future videos because I don't believe these futute games will be as City Shaper 🤔🤔🤔.

We'll have to see what the challenge is next year ;)

Also check the "Food Factor" post from May 2012.

@@hydrogenhead gonna go check for it ! But don't wait until next year !!!! Do it for this one man !!! I made a few rubber and weight actuators for this years challenge and i am still looking for improvements.

I still feel sad that the RCXs are no longer working. Sigh. As for FLL, there have been years where's I've desired a fourth motor, or a gyroscopic sensor. Not this round. Cargo Connect would have been a breeze with an NXT this year. I'll get a Spike Prime someday, I suspect. The built-in sensors sound like fun. Having said that, about the only way they would be "essential" for FLL would be if all the older hardware quit working.

@@hydrogenhead what do you mean they are no longer working ? Are they not still accepted in the competition ? Also, the gyroscope from the Spike Prime isn't so great, is just how the EV3 was supposed to be. But still, if you count on a gyro sensor, you loose speed and time in the competition, thus i would still go for the 4 color sensors setup instead of it.

@@robertsima3585 RCXs are still allowed in FLL competition, but mine have quit working. I'm more interested in the Spike Prime for non-FLL stuff.

As luck would have it, I have a laptop that may be about your age, and it talks to the infra red tower the RCX communicates with. Robotc is still available as a free download, as are all the drivers, but robotc is a slow language to program in, and learning it is a slow curve. I liked the RCX because of the small motors and sensors, and the fact that it was based on the traditional Lego design rather than Technic. This particular robot was about the smallest three-motor design I could come up with capable of attempting this year's FLL challenge.

@@hydrogenhead Yeah, I can see how compact the robot is, its incredible! In your description I saw that this model broke down, do you have any other ones to try out?

@@TechnoThornYT I do a lot of volunteer work with Lego robots locally, and a few years ago I was given six RCXs, of which two were functioning. When the last one quit I asked a friend if she still had one: she had two, but I couldn't get either one to work. The one closest to working has lost one of the three sensor inputs, so it could still be used in some limited applications. All the others have trouble with two or more sensor ports. I could buy more on ebay, of course, but since they're all getting old I'm not sure that would be a good way to go. I do like that the new Spike Prime has small motors available for it, so the prospect of building small might be coming back.

I took a break from coaching this year due to Covid, so no RePlay effort. I have several NXTs about, however, and currently have three bluetooth-controlled cars up and running.

@@hydrogenhead I still think you should get a RePlay kit and tinker with it. Due to COVID, First has pushed Championships out to summer, so you still have time to inspire this season’s teams. :)

As adults tinkering in a kids' competition we sometimes skirt a fine line between inspiring kids and demonstrating spoilers. I'm not entirely immune to this, so have tended to wait until fairly late in the season before posting solutions. Since I'm not coaching any teams this year I never gave any thought to tackling it, but I was pleased to see the launch area included as part of base this year: I had to use a resistance wheel on the side to get the bot to steer into home after the first two missions in last year's challenge. Using one motor certainly presents its challenges! I had sufficient opportunity to see what the teams are up to this year, as a remote judge. Interestingly, for our regional qualifier the teams were allowed to submit their three competition rounds via prerecorded video, which offered great video quality as compared with the live video feed used at the [Alaska] state finals the last two years (travel to Anchorage is cost prohibitive for some teams, so they opt to participate via video). I suspect the finals this year will see many teams - if not all - participate remotely. The RCX was a great machine for last year, and it's still together, as is the modular robot I used in previous years. I'm hopeful that next year's season will offer opportunities for the RCX.

@@hydrogenhead It’s good your sensitive to the idea of spoilers, but I think there’s more benefit than downfalls to posting solutions, even early in the season. It’s hard motivating middle schoolers, but what I’ve determined is that they are extremely competitive. I show my team those videos and use it as ammunition to get them going. Also, copying a solution 1:1 rarely is a slam dunk. I’ve found that it takes just as much work copying a solution than it does starting from scratch.

The limitation is with the airflow through the cylinders. I've heard of people modifying them to increase airflow but haven't tried it, so I suspect any further attempt would operate very much the same.

@@hydrogenhead it is quite simple to modify them I think. The switches are a bit hard because of keeping the sealed. There are some people who sell them pre-modified.

Just lucky?

I have another video on here titled "Straight, Left, and Right with one Servo Motor; Lego NXT" in which the bot could also go in reverse. With both of these robots the motor is used like a pendulum in a clock by repeatedly reversing motor direction. My "clock" mechanism pushes a set of gears back and forth between left and right to engage one or both wheels. A light sensor on the clock mechanism tells the bot what position the gears are in. The single-motor drive robots are among my favorite creations.

@@hydrogenhead thx

A torsion-axle spring, yes.

Very good! Any video? This was the first time I've ever seen a table where a single motor robot could be competitive. It was certainly a unique experience for the kids.

I have a fifteen year-old laptop that somehow still communicates with the internet, and was able to download a free robotc compiler onto it. All I had to do was learn robotc!

If you use the old serial towers, modern computers can still handle the RCX

@ichococookie - there is a 3rd party program called bricxcc. I know it to work with Windows 10. You will need a USB to serial adapter. I have no experience with the USB "tower", forums on this semi-obsolete hardware suggest USB tower either doesn't work or doesn't work easily. Finally, the Lego software doesn't work on modern PC with this serial adapter setup - you need to use not-quite-C "NQC" to program the brick.

The team got marked down in robot design due to the lack of sensors. It's really more a matter of perception: this bot is purpose made for the tasks required of it, and is a novel and innovative approach that works with extraordinary reliability despite its apparent simplicity. "Think Simple" is a sales pitch - Honda used it in the 1970s - the team can take to the state finals, and they have their performance at regionals to back them up.

My very first robot! Long time ago though, don't have the program any more.

I've never been any good at LDD. Sorry. I like the design because - if aimed properly - it works without fail. And paired with a single-motor robot (which always travels in a very predictable straight line) and aiming jig, the success rate is really good. The take-away concept is not so much the specific design, but the sideways motion of the two axles, one pushing the building (and two beams) north while another pushes two beams south.

And the team is close to adding several other missions too, with a month to work on them before the Alaska finals. They're all really excited: it's only the second time a Juneau school district team has qualified for state!

hydrogenhead that’s awesome! Last year my team qualified for worlds, i hope that we meet there!

Our team says they'd like to go beyond the state final. Might happen, but it'll be a heavy lift for them. Still, they've got a chance. If they go, I'll go!

No, sorry, but look closely and this device is pretty basic. Multiple axles are linked by a chain of gears, each axle only twists a little but the combined effect of several provides sufficient power to do something. The spring arm is held down by an arm added to the bot, and releases when the bot backs away. The robot is one of the simplest I've ever built. One motor. 4-wheel drive (gears linking front and back). The only fancy things are the rotation sensor (RCX motors didn't have an internal one) and the two touch sensors configured as push buttons to cycle through and execute subroutines (because the RCX has only five program slots). Any platform (RCX, NXT, EV3) would work for this concept.

Thank you . We supposse you loved a lot the RCX and you don't want to leave it! We have one too.

@@xpabo8gymkala453 ​@@xpabo8gymkala453 I was given an RCX a few years ago but never used it. This year I realized the challenge missions could all be accomplished with a one-motor robot, so I put this together (the first video in this series featured an NXT based prototype, before I thought about using the RCX). Luckily, I have an old Windows 98 laptop that somehow still talks to the internet, and it's running a legacy version of robotc for RCX I found online. The RCX barely worked, would only talk to the IR tower when the batteries were brand new, and then for only 15 minutes! So I went to JEDC (the Juneau Economic Development Council, which coordinates FIRST and other Lego activities in Alaska), and they let me borrow all their RCX equipment (I work with kids in the schools using a fleet of NXT robots on loan from JEDC). So far I've gotten three RCXs to work, one appears to be completely dead, and two others (including mine) have issues. So this is my very first RCX robot. I like it a lot, and it works very well, this year. Learning robotc has been interesting. But the limitations of the RCX are hard to overcome, most notably the lack of internal rotation sensors on the motors, only three-sensor inputs, and a five program limit. The two buttons on this robot were added to cycle through and execute subroutines, but I still had to split the program into two parts because each of the 5 program slots are apparently very small. I could add the two buttons because I needed only one rotation sensor. Still, this robot does exactly what it was designed to do, I really like the instant on/off/on ability, and RCX robots look really COOL!

I learned about torsion springs from working on real cars. Torsion springs work really well on Lego car suspensions too. But this idea actually originated with another Lego Roboteer on TH-cam last year, who explained to me that he was designing a torsion-powered device to operate the Into Orbit exercise machine (I do not know if he was successful). So when I started evaluating how I might do this mission without an accessory motor, torsion springs came to mind pretty quickly.

The most praise worthy part about this video is that you don't use ev3 or spike prime, but freaking old school RCX You have my thanks for this video, keep up tge good work, i will now proceed on watching the rest of your channel

Who knew?

😂 Juneau Lyric Opera amazes again ;)