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Attachment Design and Strategy

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  • Attachment Design and Strategy

    Since our season is done now, I'm working with the kids on last year's challenges and I want to try to teach them some new types of mechanisms they can use to design attachments. We have used sticks basically turned directly by the motors and angled boxes to help align their robot on mission models. My list of what I think might be helpful to learn includes:

    -"dog gears"
    -rack and pinion
    -passive trigger-release mechanisms (rubber band powered or whatever)

    I admit that I am not expert on these things, so the kids and I will be learning together. I've seen builderdude35's video on dog gears and several examples (without any explanations) of how to do the drop on type of attachments (with vertical motors), but I don't know where to look to learn other ideas. I would appreciate any advice you all would be willing to share.

    As a follow up question: Which other types of mechanisms (active or passive) do you think might be worth learning?

  • #2
    I think if you watch some other videos, you will see some really interesting ideas about good ways to attach errr, ummm.... attachments to the robot. I personally (and the team too) want to avoid having to pin/peg anything to the base robot. They want to be able to very quickly attach and remove the attachments. That means they have the motors placed on the base robot such that all attachments must have a Power Take Off that aligns with the output of the base robot motors.

    By the way, I would suggest that you really want that take off spinning on the vertical axis. If you have the attachment gears engaged with the base robot gears on a horizontal axis, you will have problems with the gears slipping, unless you think of a way to lock the attachment on the base robot. To clarify, if the axles of the gears between the base robot and attachment are horizontal, that is bad. They need to be vertical.

    Think of it like this. Let's say you have a square (or rectangle) robot. It's got one or two medium motors spinning vertically with gears (any kind) in a convenient place. You could probably imagine a square, one beam bigger in each direction that fits perfectly around the robot, like a sock (we like to use the 5x7 frames for this). Then if you put a gear on the attachment such that it engages with the base robot's gear, when you pick up the attachment and put it back on, the gear will be in the same place. Bada bing, bada boom, done.

    Passive attachments are always good when you can figure them out. It's always nice to be able to score points without having to use one of your medium motors. Saves that motor for another mission when you really need it.
    Norfolk, Virginia, USA
    FLL Coach and Regional Tournament Head judge since 2014


    • #3
      I think you should put away the LEGO and do something else. The big challenge I see in FLL is coming up with a realistic solution. Once you have a realistic solution it is fairly easy to implement the solution in LEGO. To make better problem solvers you need to give your kids problems to solve. Those problems don't have to involve LEGO, and may be a lot more fun if they don't. When we knew the upcoming FLL challenge was called "Power Puzzle" my girls built a working electrical generator, and then used that in a wind turbine and a hydro electric plant. If they were still together I'm sure we would have launched a hundred rockets last year and made up challenges like maximum payload, maximum altitude, closest recovery, etc...

      If you need to stick with LEGO, try putting away the table and concentrate on building mechanisms. Can I build a grabber arm that lets me pick up a LEGO piece on the floor without bending over. Can I make an arm that will pick up a bottle of water? How much weight can I pick up with a LEGO motor? How much stronger is a Large motor than a Medium motor? How much can I increase the weight if I use gears? Can I make a car that drives up a 45 degree grade? A 60 degree grade? How fast can I make a LEGO car move? There must be thousands of experiments you can perform with a Mindstorms kit because I'm sure I've performed hundreds of experiments with a Mindstorms kit and I'm not that creative.
      Last edited by Dean Hystad; 02-08-2019, 11:08 PM.


      • #4
        A whole spring and summer, to tinker. Agree with wisdom above. Forget about FLL, and don't focus all on LEGO. Lots of young minds today don't have much experience with basic building and physics. Get some wood blocks, maybe some nails, make a small lever/catapult/jack/cancrusher/etc. Go play, find a playground with a seesaw (good luck), and have kids play on this with some physics in mind. Look at balance points, numbers of small kids on one side near the end with one bigger kid closer in, etc. Hot wheels cars, ramps, friction, and timing systems. Sometimes making a "timer system" is just as good. Start with a watch, then a stopwatch, then the phone....then maybe a EV3 light sensor setup, etc. Who cares what they time, it was making a timer that was the exercise.

        Boys? All gender fluidity aside, boys love carnage. Egg drops, rolls, protection, sturdiness, rigidity, flexibility, cushion, etc. Girls? Girls love carnage too, mix it up. Rubber band spinners, geared up spinners and transmissions, how fast, how strong, haw far to shoot/fling. How accurate.

        Towers, bridges, and projectiles.

        Create. LEGO can make awesome doodle machines, auto Spirograph-like inventions. Simple X/Y plotter points and dots to make a image. Make an egg decoration machine, a simple grip to hold and egg, a motor to turn it, and kids hold markers up to it making spinning designs, etc.

        Observe. Look at construction machines, farm machines, and the everyday household machines.

        Interact. Make a human "assembly line" to produce X. Each kid is one station, that must pass item from one to another, maybe do one step. Maybe they have to stand in one spot, and only use arms. Or just one arm. Maybe they can only use thumb and palm. Can they make a paper airplane, what are the steps? Can they open a jar if only one person moves. Can they sort blue marbles from red ones if only one person on the team has their eyes open, but can't be the one to touch anything. Can they sort marbles if EVERYONE has their eyes closed.

        Imitate. Can they develop a "code" to communicate across the street using only a flashlight. In a really long school hallway and one roll of kite string, can they create something to communicate between two ends of the building?

        Impress. Can they lift very heavy objects with just a straw and a syringe pump. Can they navigate out in a large field or open area to a treasure box, using only a protractor and some basic math and waypoints. Can a team of people be more effective using additional waypoints and triangulation. Make a sundial that is pretty accurate.

        Organize. Do you have lots of LEGO parts? Have the kids organize into some part boxes or bins. Learn some of the names, sizes, etc. But mostly become aware of ALL the shapes they have to choose from. Not every solution is two beams and some black pins. Have the means to expand? Have kids make a small wishlist from Bricklink (or similar) of odd or unusual parts. Most have some old LEGO sets at home, can each bring one unusual or unique piece and challenge the team to make some creation that includes them all. Doesn't have to be mechanical or solution-focuses, can be just artful. The exercise is to find new/exciting ways to combine LEGO together.

        Associate. Got a kid super into baseball, make a LEGO mini batting cage. Someone really into skateboarding, LEGO models abound. Another into music, the EV3 can play notes, or you can make simple marble based runs that hits small bells or metallic obstacles, etc. The trick is to capitalize on something a) they are interested in and b) already have a base knowledge and set of experiences to draw from.

        Visit. Goto a hardware store. Just to walk around, look at materials, look at tools. Goto a construction site and watch em build a house or something. Goto an amusement park, not just to ride the rides - but study the rides. How do they work, what all is automated, what has to be strong, what has to flex. How does the park layout and ride queues - influence people and traffic and timing.

        YouTube. Not to watch FLL videos or tutorials. But watch boat crashes, RC races, crane lifts, parachute jumpers, and mesmerizing LED sculptures, music machines, and automatrons. HowItsMade and Mythbusters episodes also go along way.

        Fimmaker bug. Create a stop motion film of LEGO characters, or just rocks on the back porch. Or just draw one manually on a pad of paper, all old school like.

        Solving X mission successfully, often comes from having already solved lots of unrelated tasks successfully, or even failing in great style at attempting other tasks. A mindset develops for how to tackle a problem. How to measure progress. How and when to try something different.

        If you look macro and see FLL as just another smaller set of challenges to practice on while in 6th grade for example - that eventually apply to how one tackles larger questions in 11th grade....then the same holds true back micro - in that being better at FLL is built on a range of fun silly experiences and rudimentary skillsets.


        Nothing has to be overly prepared or defined with great detail on the process and goal. Just put materials and time in front of youngsters and let it breath on its own.

        From my team's experience, the most LEGO/FLL solutions like latches and creative attachments - all came from kids playing in the parts bucket making little guns, catapults, and gopro or phone holders.

        The summer is where it can really come alive, if you ask me. August will be here soon enough with rules, constraints, points, and parents-on-a-mission. Nah, summer is where the tinker heart is. Enjoy.

        Like this post, it didn't exactly answer the question that was posed. But (I think) contains many key ingredients to make them more capable of creating their own answers down the road.


        • #5
          Those are all great ideas. Thank you. Since I have the kids in an after school Lego club, I'll stick to using Legos, but we can use them to design non-fll things too. The idea of making catapults, for example, might help us figure out how to use rubber bands in FLL designs. Not downplaying any of your thoughts or ideas, but my kids still have a high level of interest in Lego robots, so I'll stick with that until I see a need to change things up (which I probably will at some point). At that point, I have a nice list of ideas to choose from.Thanks again.


          • #6
            Originally posted by Tim Carey View Post
            The idea of making catapults, for example, might help us figure out how to use rubber bands in FLL designs.
            If your kids are going to work on catapults or other items like rubber band-powered cars, they might as well also work on mechanisms by which these can be released/triggered by the robot.


            • #7
              Originally posted by dnb View Post
              If your kids are going to work on catapults or other items like rubber band-powered cars, they might as well also work on mechanisms by which these can be released/triggered by the robot.
              Yeah. That's what I was thinking.

              I also saw the idea somewhere of using gears as timers -- you put pegs into a gear, hook rubber bands over the pegs, and as the gear rotates, it releases the rubber bands (same idea would work with the pegs supporting beams that have rubber bands attached to them). If you rotate the gear 90 degrees, it releases the first mechanism. 90 more degrees and it releases the second. Kinda how a rubber band gun might work. Seems like an idea that could be fun to play around with (and also be useful).