Construction Tips LEGO Geometry

Transcription

1 LEGO Geometry The LEGO Unit A 1 x 1 LEGO brick is not a cube. It is taller than it is wide. It is 6/5 (1.2) times taller than wide. The width of a 1 x 1 brick is the standard Unit, then the height is 1.2 Units. The height of the brick is a larger measure than the length and width relationship between these dimensions: the vertical unit is precisely 6/5 times the horizontal ones. A stack of five LEGO bricks is exactly equal in height as a sixstud LEGO beam is long.. LEGO Brick A brick is a LEGO element that is at least 8mm long, 8mm wide, and 9.6mm high. Bricks are the basic building elements of LEGO System. A LEGO unit is based on metric system. The studs are used as the basis of measurement. This would be a 2 x 4 brick. Plates Plates are flat and have studs on the top. A plate is 1/3 the thickness of a LEGO brick. It takes 3 LEGO plates to equal the height of one brick. A plate is 0.4 units thick. The height of 1 brick + 2 plates equals 2.0 units. 3 bricks + 1 plate = 4 Units and 5 bricks = 6.0 units. Beams Beams have holes in their side and are one stud wide. They are measured by the number of studs on top. beams are very useful in building sturdy structures. Axles Axles are measured according to the stud system. This would be a 6 stud axles. Page 1

2 This diagram demonstrates a useful tip when trying to build sturdy structures. When you want to line up beams to use for cross-bracing, you need to make some adjustments. You can brace a stack of a TECHNIC beams and plates by connecting a TECHNIC brick vertically to the outside of the stack Frames This structure is poorly designed and will not provide enough support for the design. It will break apart very easily. Axles will rub against the sides of the holes in the beams as well. Page 2

3 Frames When building a robot s chassis, it is important to have a strong and rigid frame. This can be achieved by using wide cross beams of the same length. Cross Bracing Cross bracing allows you to tightly secure walls of beams to maintain structure integrity and stability RCX cross bracing It is important to have the RCX unit attached securely to the design. This allows the robot to be picked up easily without falling apart. The cross bracing provides strength and stability to the design. Use the small holes in the sides of the RCX unit and use the pegs or friction pins to make a secure structure. The Tools of Technic (from LEGO Design School) Beams Beams are the basic structure elements in the LEGO TECHNIC system. They provide the scaffolding, or framework, for TECHNIC models. When used with connector pegs and a few standard plates, beams will help you create very rigid structures. There are three types of beams in the LEGO TECHNIC range of elements -- half beams, beams and TECHNIC bricks. A TECHNIC beam is about 8mm wide and 8mm tall with no studs and an odd number of holes in the side. A half-beam is similar to this element, except it is 1/2 as wide, or about 4mm in width. A TECHNIC brick looks like a standard LEGO brick with an odd number of holes punched through it -- a 6-stud TECHNIC brick will actually have 5 holes in the side. TECHNIC bricks also have hollow studs on the top side of the brick. Page 3

4 Connector pegs Connector pegs are used as the fasteners of the TECHNIC world. Like screws or bolts, they hold many LEGO TECHNIC creations together. Connector pegs come in a few flavors. The first type is a standard gray connector peg, which is 16mm long and has a stop ridge in the middle of the length. It can connect two beams (or any TECHNIC elements with holes) so that they can swing freely. The next type of connector peg is usually black, and has small ribs on it that make it more difficult for the peg to turn inside the hole of a beam. These black connector pegs are also known as connector pegs with friction. There are also some black connector pegs that are a bit longer (about 24mm), with a ridge partway in on one end, and a bump partway in on the other end. Another special connector peg has an axle on one end; this peg may be gray or tan, depending on when it was manufactured. When using connector pegs to lock beams, be sure to measure the distances properly, so you don't put unnecessary stress on the pegs. Also, it is not a good idea to push anything into the hole at the end of a connector peg if the peg is already in a beam. Basic Building with TECHNIC Beams There are two basic rules for building stable, or rigid, structures and reducing the amount of stress on the elements used in the framework of your TECHNIC model. Basic Rule 1 When you connect TECHNIC beams to make a triangle, the triangle must contain one right angle. A right angle is a 90-degree angle, like the corner of a square, or the letter L. When building at a right angle, one beam is said to be perpendicular to another beam, or crosses it in a straight line, like the lines of a plus sign (+). Basic Rule 2 The distance between every other hole on a TECHNIC brick is equal to the height of two beams with two plates sandwiched between them. This measurement relationship allows you to use TECHNIC bricks to brace a structure. To brace a structure using TECHNIC bricks, first stack a beam, then two plates, and finally another beam. Next, connect a TECHNIC brick vertically to the outside of your stack using connector pegs to lock the stack in place. This outer TECHNIC brick must be aligned perpendicularly to the stack in order to line up properly with the open holes of the horizontal beams. A TECHNIC axle is a small rod which usually passes through the middle of a wheel or gear and turns at the same speed as the gear or wheel. The cross-section of a TECHNIC axle looks like a plus sign (+). Most TECHNIC axles, which range in size from 16mm through 96mm, are black or gray in color. Page 4

5 Gears see separate sheet Wheels vs. Treads There are many possibilities in the LEGO kit. Tank treads are commonly used for locomotion. The typical setup involves using a 16 tooth spur gear inside the white tread hub. Vehicles that use two tank treads can turn by spinning the tread in the opposite direction. This is referred to as skid steering. Four Wheel Drive One drawback to treads or skid steering is that it has a great deal of friction and tends to be quite slow. The treads can be replaced with closely spaced wheels that result in a very manoeuvrable and fast method of locomotion. Programming Notes Turing the motors in the opposite directions results ia a robot that turns on the spot (zero turning radius). Turning on the left motor while stopping the right will result in a right turn that pivots about the right wheels. Running the left motor faster than the right results in a large turning radius right turn. Page 5