Placing and Fitting Gears

LEGO Mindstorms NXT hobbyist, how are you? I hope you is still motivated for following my posting. Lets We learning about gears again.It is continue topic before, about Limiting Strength with Clutch Gear. The LEGO gear set includes many different types of gear wheels. Up to now, we played

with the straight 8t, 24t, and 40t, but the time has come to explore other kinds of gears, and to discuss their use according to size and shape. In studless buildings, unlike traditional studded building, the holes in TECHNIC beams stacked atop one another are the same distance apart as holes in a single beam. This means gears connected together will be the same number of holes apart, whether connected horizontally along the same beam or vertically across multiple beams (see Figure

2.7 and Figure 2.8).

Figure 2.7 Vertical Matching of Gears

Figure 2.8 Matching gears horizontally and vertically

Limiting Strength with the Clutch Gear

LEGO Mindstorms NXT hobbyist, This topic is continue our topic about playing with gear: worm gear. Another special device LEGO Mindstorms NXT hobbyist should get familiar with is the thick 24t white gear, which has strange markings on its face (Figure 2.5). It is a clutch gear, and in the next part of this section we'll discover just what it does.

Figure 2.5 The Clutch Gear

Worming Your Way: The Worm Gear

LEGO Mindstorms NXT hobbiyst, Do you remember about the geartrain in the past my posting?
This posting, I dont review it.  We will learn about the worm gear. Do you know the worm gear? In your NXT box, you've probably found another strange gear, a black one that resembles a sort of cylinder with a spiral wound around it. It is called worm gear. Is this thing really a gear? Yes, it is, but it is so peculiar we have to give it special mention.

In Figure 2.4, you can see a worm gear engaged with more familiar gears. The assembly on the right uses a special LEGO part. It is called a worm gear block. With this single piece you can connect the worm gear to a 24t gear. In just building these simple assemblies, you will discover many properties. Try to turn the axles by hand. Notice that although you can easily turn the axle connected to the worm gear, you can't turn the one attached to the other gears. We have discovered the first important property: The worm gear leads to an asymmetrical system; that is, you can use it to turn other gears, but it can't be turned by other gears.The reason for this asymmetry is, once again, friction. Is this a bad thing? Not necessarily. It can be used for other purposes.

Figure 2.4 Worm Gears Engaged with Other Gears

Riding That Train: The Geartrain

LEGO Mindstorms NXT hobbyist, Before... we have learn about Gearing up and down. All right.. we continue to learning about gears. The largest LEGO gear is the 40t, and the smallest is the 8t (used in the previous discussion). Thus, the highest ratio we can obtain is 8:40, or 1:5 (Figure 2.2).

Figure 2.2 A 1"5 Gear Ratio
 

Gearing Up and Down

LEGO Mindstorms NXT hobbyist, do you remember to counting teeth of gear in the past my posting? Now, lets we continue to learning about gearing up and down. Let's start turning the larger gear in our example. It has 24 teeth, each one meshing perfectly between two teeth of the 8t gear. While turning the 24t, every time a new tooth takes the place of the previous one in the contact area of the gears, the 8t gear turns exactly one tooth too. The key point here is that you need to advance only eight teeth of the 24 to make the small gear do a complete turn (360 degrees). After eight teeth more of your 24, the small gear has made a second revolution. With the last eight teeth of your 24, the 8t gear makes its third turn. This is why there is a difference in speed: For every turn of the 24t, the 8t makes three turns! We express this relationship with a ratio that contains the number of teeth in both gears: 24 to 8. We can simplify it, dividing the two terms by the smaller of the two (8), so we get 3 to 1. This makes it very clear in numerical terms that one turn of the first corresponds to three turns of the second.

You have just found a way to get more speed! (To be technically precise, we should call it angular velocity, not speed, but you get the idea.) Before you start imagining mammoth gear ratios for race car robots of LEGO Mindstorms NXT, sorry to disappoint you~there is no free lunch in mechanics; you have to pay for this gained speed.You pay for it with a decrease in torque, or, to keep in simple terms, a decrease in strength.

Playing With Gears

Hello world! Hello LEGO Mindstorms NXT hobbyist! Now, We will learn about playing with gears. You might find yourself asking "Do I really need gears?" Well, the answer is yes, you do. Gears are so important for machines that they are almost their symbol: Just the sight of a gear makes you think machinery. In this posting you will enter the amazing world of gears and discover the powerful qualities they offer, transforming one force into another almost magically. We'll guide you through some new concepts~velocity, force, torque, friction~as well as some simple math to lay the foundations that will give you the most from the machinery. The concepts are not as complex as you might think. For instance, the posting will help you see the parallels between gears and simple levers.
 

LEGO Mindstorms NXT hobbyist, are you ready? We invite you once again to experiment with the real things. Prepare some gears, beams, and ames to replicate the simple setups of this posting. No description or explanation can replace what you learn through hands-on experience.

TECHNIC Liftarms: Angles Built In

How are you LEGO Mindstorms NXT hobbyist? I hope, You still remember about Tilting the LEGO World: Diagonal Bracing. This posting continue it. As noted earlier, over the past several years LEGO has introduced a number of new TECHNIC parts that divert from the concept of straight beams and 90-degree connectivity. We could review numerous parts here, but there simply is not enough room in the my posting for this. Some of the more popular ones fit in the common group of studless beams, called l/ftarms. They come in many shapes and sizes, you can use them to connect parts at differing angles, and you often see them in robot grabbers, fingers, ball casters, and so on. Figure 1.9
shows a sample ofliftarms from the TECHNIC line.

Figure 1.9 A Variety of Liftarms

Tilting the LEGO World: Diagonal Bracing

Hello, LEGO Mindstorms NXT hobbyist! Who said that the LEGO beams must connect at a right angle to each other? The very nature of LEGO is to produce squared things, but with the advent of studless parts, diagonal connections are mainstream now, making our world a bit more varied and interesting, and giving us another tool for problem solving. 

Lego Mindstorms NXT hobbyist, this posting relate past posting about squaring lego world vertical bracing. You now know that you can cross-connect a stack of plates and beams with another beam. And you know how it works in numerical terms. So how would you brace a stack of beams with a diagonal beam? You must look at that diagonal beam as though it were the hypotenuse of a right-angled triangle. Continuing from the previous sample, Figure 1.8 adds a cross-brace to support the structure and provides a sample for this next bit. Now proceed to measure its sides, remembering not to count the first holes, because we measure lengths in terms of distances from them. The base of the triangle is eight holes. Its height is six holes: Remember that in a standardized grid, every horizontal beam is at a distance of two holes from those immediately below and above it. In regard to the hypotenuse, it counts 10 holes in length.

Squaring the LEGO World: Vertical Bracing

Welcome back Lego Mindstorms NXT hobbyist... We continue our discuss about building robots with lego mindstorms NXT past time. Why do we care about all these relationships? To answer this, we must travel back to the late 1970s when the LEGO TECHNIC line was created. Up to that time, LEGO was designed and used to build things made of horizontal layers: Bricks and plates integrate pretty well when stacked together. Every child soon learns that three plates count for a brick, and this is all they need to know. But in 1977, LEGO decided to introduce a new line of products targeting an older audience: LEGO TECHNIC. It turned the common 1 x N brick holes into what we call a TECHNIC brick, or a beam (Figure 1.5, left). These holes allow axles to pass through them, and permit the beams to be connected to each other via pegs, thus creating a whole new world of possibilities.

In the late 1990s, the advent of studless beams (Figure 1.5, right) opened the door to alternative building options. One of the best sets in TECHNIC history is undoubtedly the 8448 Super Street Sensation, which is built almost entirely from studless parts. LEGO was clever with its approach here. Instead of using beams to construct the chassis and plates to provide the "shell" or "form" for the model, the chassis was built using studless beams and its style was handled by fairing panels, allowing the curves of the car to "flow" with the design. LEGO did this to reduce costs: Less material required equals a cost savings in production. You can see a great example of this if you compare the 8448 Super Street Sensation to the classic TECHNIC 8880 Supercar. Compare their approaches to construction, and their weight.You will notice significant differences. The 8880 gets all its design cues from classic TECHNIC beams, whereas the 8448 uses fairings and flex axles for its design.

Figure 1.5 The LEGO TECHNIC Beams

Building Robots With Lego Mindstorms NXT

Introduction

Before you enter the world of LEGO robotics and building robots with Lego Mindstorms NXT, we want to be sure you know and understand some basic geometric properties of the LEGO bricks and beams. Don't worry; we're not going to test you with complex equations or trigonometry. We'll just discuss some very simple concepts and explain some terminology that will make assembling actual systems easier from the very beginning. You will discover which units LEGO builders use to express sizes, the proportions of the bricks and beams, and how this affects the way you can combine them with different orientations into a solid structure.

In the past few years, there has been a shift from building with TECHNIC bricks and beams to building with studless beams, pins, and connectors. After we introduce some basic concepts, you will be exposed to these new ideas and see examples of how you can use studless building. We encourage you to try to reproduce all the examples we show in this chapter with your own LEGO parts. If for any reason, you feel that what we present is too complex or boring, don't force yourself to read it. Skip the chapter and go to another one.You can always come back and use this chapter as a sort of glossary whenever you need it.