DataWires

By Sanjay and Arvind Seshan

INTERMEDIATE PROGRAMMING
LESSON

DATA WIRES

Data Wires

A Data Wire allows you to take an output from one programming block and input
it into another.

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Input
Output

Multiple Choice

Why are data wires important? or useful?

• Data wires are used for cooking food
• Data wires are essential for watering plants and plants are thirsty. Just listen to them.

• Data wires allow you to repeat one programming block over and over again in 2 horzontal rows.

• Data wires allow you to take an output from one programming block and input it in another.

Data Wire Types

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Data Type

Input

Output

Output Data Wire

Logic

True or False

Numeric

Number

Text

Text

Numeric
Array

Logic Array

Images from EV3 Help

Multiple Choice

Logic that can only have two outputs is also known as what?

• Irish

• binary

• decimal

• boolincoln

Automatic Data Wire Conversions

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From Data Type

To Data Type

Output/Result

Logic

Numeric

False = 0, True = 1

Logic

Text

False = “0”, True = “1”

Logic

Logic Array

Array with one element

Logic

Numeric Array

Array with one element (0 or 1)

Numeric

Text

Text that represents a number

Numeric

Numeric Array

Array with one element

Logic Array

Numeric Array

Same size array with all elements equal to 0 or 1

Content from EV3 Help

These conversions are automatically performed in the programming blocks. For
example, you are allowed to connect a numeric value (like what color a sensor sees) to a
text value (on a display block).

Fill in the Blank

How are data type conversions completed in Ev3 programming?

How to Create a Data Wire

The block with the output must be
placed before the block with the input

The input and the output must be the
same data type or one that can be
automatically converted (see slides 4
and 5)

1. Click on the output on the block

2. Hold and drag the wire.

3. Move the icon into the correct input
and then let go of the mouse

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5

1

2

3

Images from EV3 Help

Reorder

Reorder the following steps to create a data wire in the correct order

• place the output block

• place the input block

• Click on the output on the block

• Hold and drag the wire.

• Move the icon into the correct input and then let go of the mouse

1

2

3

4

5

• 1
• 2
• 3
• 4
• 5

Sidebar: Display Block - Wired Mode

The Display Block can be used in wired
mode to display data from another block
to the screen.

For the challenge, you will need to display
a number on the screen. Pick Text Mode
🡪Grid from the bottom left corner of the
block.

To pick Wired Mode, click on the top right
corner of the Display Block and pick wired

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Data Wires Challenge

CHALLENGE: Make your robot drive forward slowly over different colors. Have the
robot display the color the color sensor sees as it moves. Stop when you hit a
button on the brick.

STEP 1: Turn the motors on in a Steering Block and drive slowly forward

STEP 2:

◦ Inside a Loop, add a Color Sensor block.
◦ Add a Display Block in Wired, Text Grid Modes.
◦ Wire the Sensor Block’s output into the Display Block’s

text input (first input)

STEP 3: Exit the loop when a brick button is pressed

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More Complex Wiring: Switches

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A.

If you want to drag data wires out of
switches, you will need to change the
switch to tabbed view

A

B

B. Once you switch to tabbed view, you can
drag data wires out

C. Different options in the switch can
connect to the same wire

More Complex Wiring: Loops

You can connect wires both into and out of a loop like in the example below

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• Note that the data coming out of the loop through the wire will only be the last pass

through the loop.

• In the example above, the color sensor is read twice in the loop. However, the data

wire will only have the second (and last) reading and that second reading will be
displayed.

Going
into the
loop

Going
out the
loop

Credits

◦ This tutorial was written by Sanjay and Arvind Seshan
◦ More lessons at www.ev3lessons.com

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This work is licensed under a Creative Commons

Attribution-NonCommercial-ShareAlike 4.0 International License.