Tips n Tricks

Program Brief
Look at the pic and it will show you how to open the program brief.

Rename a robot To rename a program, go to the Program Vault in the Robotics Invention System 1.5 RCX software. Then click on the name of the program (in the Programs window, not the Program name window) you want to rename, wait two seconds, and click the name again. Now you can delete the old name and type in a new name.

Little Base
Here's a way to build an alternative driving base for your Robotics Invention System. It's easily adaptable which means that you can add and remove parts (i.e. wheels, sensors, etc.) to it. The base, called Little Base, will work with versions 1.0 and 1.5.

Little base part 2
Last week, I said that Little Base was modular. Here's a module for it, a wheel attachment that allows your robot (after it is programmed) to walk. The legs for the right and left side of the robot are slightly different. Here are some images of each side to help you construct it:

Back

Front

And thats the little base.

Rename a robot To rename a program, go to the Program Vault in the Robotics Invention System 1.5 RCX software. Then click on the name of the program (in the Programs window, not the Program name window) you want to rename, wait two seconds, and click the name again. Now you can delete the old name and type in a new name.

Light Seeking Program Earlier on you learned how to build a robot that resembled a bug. Now you can use this program to make your robot scurry around your room as it looks for a dark place to hide. First, you need to attach a Light Sensor to the Little Base.

Then, download this program and run it.

Building Sturdier Robots
If you are having a problem with your robots disassembling themselves, build your robots out of long beams. Then use smaller beams and connector pegs to connect all the beams together. This design is much stronger than just stacking the bricks.

Basics

Ataching a motor.
You can use wires to connect motors or lights to the three black output ports on the RCX: A,B and C. You can connect a wire to a port in 4 different directions. You can also connect the other end of the wire to a motor in 4 different directions.

Stoping and starting your robot. You can use several different kinds of RCX Code blocks to start and stop motors and lights attached to your RCX.

With this simple On For block, you can turn on a motor or a light for a specific amount of time.

You can do the same thing with this combination of stacked blocks. The advantage here is that you can insert other commands for the RCX to run while the motor light is on.

Turning One of the easiest ways to steer a LEGO MINDSTORMS robot is by using two motors: one powering a wheel on the left side and the other powering a wheel on the right. To turn you just apply more power to one wheel than the other.

My Commands If your RCX code programs contain many blocks, you can use My Commands to help keep things organized. My Commands replace a long stack of commands with a single block.

Right-clicking on the Program block lets you choose how to download your program to the RCX.

Reinforcing Your Robot.
LEGO MINDSTORMS pieces are quite strong. However, to make a really tough robot you need to learn how to combine pieces to reinforce each other. One particularly good technique is to combine connector pegs with beams.

Slowing Down Your Robot With Gears
Gears are a way to slow down the wheels or other motorized parts of your robot.

By connecting a motor to a moving part through a combination of gears, you can get the part to move more slowly, but with more power.

Slowing Down Your Robot With Set Power.
You can insert the Set Power block into your program to adjust the speed of your motors. Right click the Set Power block to select a speed. Click the check mark to accept your change.

When you run your program, the new speed setting stays in effect until the next Set Power block or until you turn off the RCX.
Program slots are where the RCX stores programs in memory. Programs stay in the RCX memory until the batteries wear out or you remove them. There are 5 program sots on the RCX. To run any of these programs, select a slot by pressing the Prgm button on the RCX. When the program number you want to run appears in the RCX display, press the Run button on the RCX.
Press the Prgm button to choose a slot.

When you set up your RCX for the first time, each slot contains an example program. The programs in slots 1 and 2 are especially helpful for testing your RCX.
Slots 1 and 2 cannot be overwritten by programs you create and download from the computer. This means slots 1 and 2 are locked and you cannot store your own program in the first two slots. Use Setup Options on the LEGO MINDSTORMS CD-ROM to select which slots are locked.

Building Tricks
Card Reader

Here are some pictures that should help you build a Card Reader. This invention uses one motor, one Touch Sensor, one Light
Sensor, and some bricks. So the card won't move too fast , the motor is geared down by a belt-drive. An 8 toothed gear, attached to an axle, allows the card to move.

Building the cards Last week we introduced a Card Reader. Here is a simple way to build something for the Reader to read. The black and white tiles in the image below are not included in the Robotics Invention System. If you don't have these bricks, just print out the Tile Print image and tape it to the card. You can also make more tile sheets of your own.

Two Sensors, One Port You can wire two (or more) Touch Sensors to a single input port. Just attach one end of each wire to the sensor and the other end to the same port (for example, two motors to port A).

Use this trick when you want to run two sensors from a single program block. With Two Single Sensor Bumpers and a Reverse RCX Code block, you can easily make your robot move back and forth.

Another little base Remember the little base, well I put the two motors back to back, with no gap in the middle. This made the robot incredibly strong and durable.