Lego Engineering Tips
The steps to creating a winning creature
January 2015
Introduction
Welcome to Engineering 12 with Ms. Tevlin! It may seem like a breeze to some of you, and to others it might be harder than you thought. Regardless, for the project you’re about to endure there are some important things you should know. To start, this isn’t your average elastic band powered Lego car, now you’re in the big leagues. Using motors and gears effectively may seem overwhelming and you may not even know how, but it’s important to not overthink it. Often times, simplicity equals success. Attempting to create a large complicated connection of gears and axels won’t always work out as well as you thought; some of us had to learn that the hard way. As well, a major issue that could come up is the fact that decorations are a must and you simply may not have time after trying to make a big huge complicated machine. Time management is key, without leaving a class or two at the end of the project it’ll be difficult to complete the decoration portion of the project by the due date. In the examples following you’ll learn three motions that could help you in your creations of Lego genius. Provided will be five examples of possible applications for each movement, but there’s always possibility for more applications not listed. Imagination in the brainstorming of your project is highly important, so put those minds to the test. Beside the title of each movement there is a YouTube link that will allow you to see the motion in action.
1. Cam Lift
Description of movement: This motion allows for two different sized cams to be bouncing a plate on top of them. Depending on the speed that the cams are spinning at, the plate on top may simply be moving up and down, but that’s all part of deciding the affect you want your motion to have.
Steps of Creation / Photos presenting the stepsAttach a single long axel to the motor provided using an axel extender. /
Attach first a large cam approximately one quarter of the way down the axel, and attach a small cam to the very end of the axel. /
Build a support system surrounding the motor and beginning portion of the axel upon which the hinge will be placed. /
Attach a plate to the support system using hinged Lego pieces. Ensure that the plate rests on top of the two cams attached to the axel. /
A head or other decorative piece can be added to the hinge mechanism in order to make it more lifelike. In the example presented to the right a dragon’s head was added to indicate a mouth moving. The head was attached using materials such as pipe cleaners, although the manner in which the object is attached may vary. /
Applications
This movement allows for many actions to be created when making a lifelike creature. Some examples of applications of this movement are:
A jaw (as seen in the example)
Flapping wings
A moving tail
A jumping motion
The action of throwing
Video of final motion:
2. Lego gear train movement
Description of movement: This movement makes two gears act as if they are working like a train. One gear is propelled by the motor while the other is propelled by the beam that is attached to the first gear. Due to the gears being offset and onlyone gear being moved by the motor itself, the bottom gear will spin a full circle while the gear on top will only move back and forth slightly (a highly useful action to have).
Steps of Creation / Photos presenting the stepsAttach a single long axel to the motor provided. /
Build a small wall using beams allowing the end of the axel to rest within the hole of a beam. /
Attach a large gear to the very end of the axel. Insert a connecter peg into one of the holes on the inner circle of the newly added gear. /
Build the wall higher on one side, allowing for another gear to be secured in place and not touch the original gear. Insert a connecter peg into one of the holes on the outermost circle of the gear. /
Attach one beam to both gears using the connecter pegs that were previously inserted into the gears. This will allow the rotation of the lower gear to provide movement to the higher gear. /
Applications
Through the use of this movement there are some applications that one might find useful when creating a moving creature/object. Some examples of applications include:
A walking movement
A pushing movement
The appearance of something climbing
A punching movement
A controlled flailing movement
Video of final motion:
3. The Elastic Band Snap
Description of movement: This movement is caused by an elastic band and a cam. The cam will rotate at a slow pace (due to the gear box slowing down the rate that the axel spins) and will lift up a free hanging beam. An elastic band that is attached to the beam and the ground will cause great tension as the beam gets lifted by the cam. As the cam reaches its full rotation and loses contact with the beam, the elastic band will allow the beam to smack back down into place. This means that no matter how many times the cam lifts the beam, the beam will always go back to its original spot and the cycle can continue.
Steps of Creation / Photos Presenting the StepsMake a base for the Lego motor to be placed on using plates. Attach a medium sized axel to the motor using an axel extender. On the opposite side of the base attach a beam. /
Attach a gear box with a worm gear to the axel attached to the motor. Ensure that the gear box is firmly in place on the base. /
Place a medium sized gear into the top of the gear box with an axel going through the middle hole facing towards the beam placed at the end of the base. /
Put a small cam at the end of the axel that is sticking out of the gear box. /
Make a small tower out of blocks, on which a small beam will be secured. Attached to this beam will be another beam using a small connecter peg. This will allow the second beam to swing freely while the original beam will stay secure. /
Finally, attach the free swinging beam to the beam attached to the base using an elastic band. As shown in the pictures to the right, this will allow the beam to be moved up by the cam, but snap back into place once the cam has kept rotating. It is important to ensure that the elastic band is attached loosely enough to allow for ample movement of the beam, and not cause anything to be pulled out of place due to excessive tension. /
Applications
This movement allows for creativity and possibilities when creating something out of Lego. Some applications of this motion include:
Due to the snapping sound that this motion makes, it could act as a noise maker
Could be used to demonstrate something twitching
Acts as a controlled open and closing motion; whether that applies to a jaw, or something that it is not lifelike
Could act as arms\legs
Hitting motion indicates that it could act as an object such as a hammer
Video of final motion:
Conclusion
As shown in the examples given, there are many possibilities for creativity to emerge and for lifelike creatures and a plethora of objects to be made and applied during this project. One of the vital pieces of information that must be conveyed is the fact that although there are many complicated and cool looking motions that can be made they are simply not a reasonable option during the project. Essentially, if it takes multiple classes to build one action that drives your machine/creature, it’s often not worth it. The three options presented in this example allow for a total of fifteen different possible movements, and there are more that can be thought of through the work of the imagination. Not only do the examples provided allow for many different motions, they are also quite simple to build. These actions are efficient, they are sturdy, and they are reliable. It was found through experimentation that although one large idea may seem like a good idea in theory, there are often complications that arise, or the structure is shaky and breaks on regular occasions. This may not always be the case, however when completing a project with a strict timeline it causes any issues that arise to be large issues and simply add unneeded pressure. As well, when making one complicated motion it can take away from the ability to have variety in your creation. Many points go towards the complexity of what is made and the amount of motions it has, not just how good a motion is. It is important that the amount of motions that can be made is high in order to maximize success in the competition. The important fact of the matter is that simplicity is sometimes the best possibility. The goal isn’t to over think it, it’s just to make something fun and exciting with a multitude of actions. As well, it’s important to remember that at the end of the day, you can have this great motion that looks like it could be cool, but if it’s not decorated and if it doesn’t look like anything other than a bunch of Lego pieces smashed together that move, you aren’t going to win. Decorations can be tricky, and we’ve encountered it first-hand. Some décor pieces that come from outside sources can be quite heavy and for some motions it’s hard for the motor to take that much weight. For example, the dragon head on the cam lift had to be strategically held in place as to not put too much weight on the motor and axels. It’s also imperative that you have a fully charged battery or your movements will run slower than normal. If something is too heavy for the Lego to handle, you may have to replace it. Essentially, leave a day or two to decorate. So good luck, keep it simple, and make sure you leave time to make it look good too!