Move Steering

The move steering block controls 2 motors at a time, in sync. If the robot is built like a car, (like the picture shown below) with the two motors attached to wheels, this block will come in handy on many occasions. Just like the medium motor and large motor tutorials, you can code this block to move however many rotations/degrees/seconds you want, but instead, you can move two motors at a time instead of one.

Move Steering Block

Standard EV3 Two-Motor Driving Robot

http://robotsquare.com/2013/10/01/education-ev3-45544-instruction/

Tutorial

When you drag the move steering block to the screen it should look like this:

Unlike the medium motor block and the large motor block, there are actually six main components to this block. The first one is the little circle with a "#" symbol in the middle.

When you mouse over this spot, it will turn blue and say "On for Rotations". This tells you what mode the block is set to. There are five modes: Off, On, On for Seconds, On for Degrees, and On for Rotations. These options tell the two selected motors what to do when the program is run. Each option tells the motors to do something completely different, and each one is important when programming your robot.

"Off"- This options turns both motors off and locks them in place
"On"- This option moves the motors forward at a given speed. To control how long they are "On" for, put this block inside a loop block
"On for Seconds"- This option spins the two motors at a given speed for the number of seconds you type in
"On for Degrees"- This option moves both motors forward or backward depending on how many degrees you want them to turn. Just like the other options in this list, the motors spin at a given speed
"On for Rotations"- This is the default setting when you first drag the block into the workspace. This option spins the two motors a complete 360 degrees for every rotation you type in. For example, if you type in 3 rotations, the motors will move a total of 1080 degrees forward. As usual, the motors will spin at a given speed

The second main component to this block is the driving angle, or steering. The steering is located right under the arrow pointing up, to the right of the drop-down options menu. This input will change the angle in which the robot moves. The default value is 0, or straight forward.

To change the steering, simply click on the box with the "0" in it. A horizontal slider will appear (like the image to the left) and the "0" will highlight or turn blue. To change this input, either type in the value you want or use the slider to set the value you want. The maximum value allowed in this input is 100 and the minimum, -100. Changing this input will change what angle the EV3 moves. For example, if you type in 50 for this input, the EV3 will start to move right at that angle. If you type in -50 for this input, the EV3 will start to move left at that angle.

The steering input will make the robot turn right or left depending on what number you type in, but keep in mind that the value is not exact. For instance, typing in 90 for the steering will not turn the robot at an exact 90 degree turn. It will only adjust how fast or how slow the robot turns right or left. Trying to make the robot turn an exact 90 degrees depends on what the steering value is, what the rotations are set to, the speed of the motors, and how much charge is left in the robot.

The third main component to this block is the power level, or speed. The speed is located right under the image of the speedometer with the red pointer. The default setting for the speed when you drag the block onto the workspace is 75.

To change the speed, (or power) click on the 75. It will highlight itself, and then you can change it to any number between -100 and 100. Another way to change the speed is by using the slider bar underneath the number. The line in the middle of the slider indicates 0, or no power. If you change the power to 0, no matter what number you type in for the rotations, degrees, or seconds box, the motors will not move.

As a default, the two motors will always spin forward. To make the motors spin backward, set the power (speed) to a negative number. For example, if the speed is 75 and you want the EV3 to move backward at the same speed, change the speed to a negative, or -75. This tells the motors to spin backward at a speed of 75.

The fourth main component to this block is the rotations/degrees/seconds. Each time you change the menu to a different option, (besides on and off) this component changes, as seen below.

This option, "On for Rotations" changes this box to a value of 1 when you first select this option. Changing this number will change how many times the motors spin a complete 360 degrees. For example, if you type in 4 for this box, the two motors will spin forward 1440 degrees. Changing this box to -4 rotations will make the them spin backward 1440 degrees.

Note: You can also change this block to a decimal if you don't want the two motors to spin a complete 360 degrees. For instance, setting the block to 2.25 rotations will make the motors spin 810 degrees. (2 full rotations and one fourth of a rotation)

This option, "On for Degrees" changes this box to a value of 360 when you first select this option. Changing this number will change how many degrees the motors spin. For example, if you type in 270 in this box, the motors will spin forward 270 degrees. Changing this box to -270 degrees will make the motors spin backward 270 degrees.

This option, "On for Seconds" changes this box to a value of 1 when you first select this option. Changing this number will change how many seconds the two motors spin for. For example, if you type in 6 in this box, both motors will spin forward for 6 seconds.

Note: You cannot change the seconds to a negative number. If you do, it will just change into 0, and the motors will not spin. To make them spin backwards, change the speed to a negative number instead.

Another way to make the two motors spin backward is by changing the rotations or degrees (not the seconds) into a negative number. For example, if you set the move steering block to 180 degrees, the motors will spin forward 180 degrees. By changing this value to -180 degrees, the motors will spin 180 degrees backward. However, do not change the rotations or degrees to a negative number and change the speed to a negative number, as these negatives will cancel each other out and the motors will continue spinning forward.

The fifth main component to this block is the brake box. (It's the box with the check mark) This tells the two motors if they should slow to a stop when they are done completing the number of rotations/seconds/degrees inputted or just brake and come to a complete and sudden stop.

To change whether or not the motors come to a slow or a sudden stop, click inside the box with the check mark in it. The drop-down menu will show you two options, like the image to the right. The first is the default option, the immediate, sudden stop. (The check mark) The second option in the list is the slow stop with the two triangles, one gray, and the smaller one, red. (The "X" mark) Once you select one of the two options, it will automatically update the block and will tell the two motors whether or not to come to a sudden stop or a drifting stop.

The sixth and final main component to this block is the port. This is the box with the capital "B+C" in the top right corner of the block. This box tells the Brick (the brain of the robot) which port the two motors are plugged into. The motors can be plugged in port A, B, C, or D, but the default ports for the large motor are ports "B" and port "C", "B" for the left motor, and "C" for the right motor.

To tell the Brick what port the two motors are plugged into, click the "B" in the rectangular box, or click the "C" in the box, depending on what motor you want to change the port to. Clicking the "B" will change the left motor or whatever motor is plugged into port B. Clicking the "C" will let you change the right motor or whatever motor is plugged into port C. The block will automatically update, and tell the Brick what port the two motors are plugged into. Don't worry about the port with the square shape right now, but it will be explained later on in this tutorial. If you click a port that either motor is not plugged into, either the motor that's port is incorrect will not spin and the program will freeze, or it will spin any other motor that is connected to the port you selected.

These six components are all you need to know in order to program the two motors to spin as long as you want and in any direction, either forward or backward. Click the next button at the bottom of this page to move on to the next tutorial, or click the previous button at the bottom of this page to go back to the previous tutorial. You can also use the menu button at the top-left corner of the screen to jump straight to any tutorial or page you select.

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