EV3 WorkshopOct 3, 2015

Instructor: Chris CartwrightAssistants: Chris Parker and Matthew Ryan

Lawrence Technological University

Lego EV3 robot used - SP

Color Sensor

EV3 Computer

Left Motor: B

Right Motor: C

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Touch Sensor

Sonar Sensor

• Left Motor connects to B• Right Motor connects to C

• Center Color sensor connects to port no. 1• Left Color sensor connects to port no. X• Sonar sensor connects to port no. 3• Touch sensor connects to port no. 4• Sound sensor connects to port no. X

X: not used in this workshop

Remember the connections!

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• Examples are using EV3 software Version 1.1.0• EV3 brick Firmware version: 1.60 (V1.06E.bin)• All example programs in

paradeWorkshop2014.ev3 (project)

• Free (Home Edition) version – Google search “EV3 software download”http://www.lego.com/en-us/mindstorms/downloads/software/ddsoftwaredownload/download-software/

Also need to download Ultrasonic.ev3b and select Tools> Block Import

EV3 Versions Used

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Mission 0:Go straight for 2 seconds using

different power levels

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LAUNCH

LEGO MINDSTORMSEducation EV3

paradeWorkshop2014.ev3

OR

Go forward for 2 seconds with power level 40 %

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EV3 offers two move blocks

Move Steering Block: Controls and regulates two motors with a steering input and single power level. (+) steering = right; (-) steering = left

Move Tank Block: Controls two motors with a power level to each motor

In this course we will use the Move Steering Block.

Green!

• Connect the EV3 to the laptop (if this is the first time, then a “Found New Hardware” message will appear)

• Click on the ‘Download’ button• It’s recommended to always unplug the

cable from the bot before running the program

• Navigate through the EV3’s menu:– Turn On > My Files > Software Files– Then select your program and run it!

Let’s test it

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• How many centimeters when 40% power used?

• How the robot is traveling when 80% power used?

How to find out the current battery voltage level?

Distance traveled

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EV3 large servo motors: geared motor with built-in rotation sensor

Rotation sensor gives “degrees” turned. (It can also give “rotations”)For example, if the value is 360, the motor turned one rotation.

Display the “rotations” when the bot goes forward for 2

seconds

Mission 1:

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Display the “rotations” turned from going forward for 2 seconds

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Program: DispRotations.ev3p

Tip: After in “T” text mode, click here and select wire

• Number of rotations = degrees / 360• Circumference (C) = diameter (D) * 3.14 • Travel distance = number of rotations (N) *

circumference of the wheel (C)• Speed = distance / time

Math Review

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D

C = D * 3.14

1) We can get number of rotations for 2 seconds by choosing “Measure – Rotations”

2) If the circumference of the wheel is 17.6cm (5.6 x 3.14), what is the travel distance for 2 sec?

3) Then what is the averaged speed of the robot for the 2 seconds?

Note: RoboParade has min and max speed limits. 9 – 18 cm/sec

How to calculate the average speed of robot for that 2 seconds ?

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• If at 1pm your mom’s car is at mile marker 5,000 and at 3pm your mom’s car is at mile marker at 5,120, what is the average speed of your mom’s car?

How to calculate average SPEED?

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distance

Time 2Time 1

Example: If the number of rotations = 2.8

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Display the “speed” when the bot goes forward for 2 seconds

Mission 2:

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Display Speed for 2 Second Drive

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Check the port

Program: DispSpeed.ev3p

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Ultrasonic Sensor• Uses the same scientific principle as bats• Can measure in centimeters or inches• Large objects with hard surfaces return the

best readings

Data from www.ev-3.net/en/archives/844

(a) About 20 degrees(b) About 60 cm(c) About 22 cm

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• When the robot is connected (USB or Bluetooth) to your computer:

• On the robot: Third tab –> Port View

Test your Sonar Sensor and read data NOW!

How to get (read) sensor data

Tip: reconnect the cable, if it does not work

• Wait: time, touch sensor, …• Loop: endless, count, …• Loop interrupt• Decision making using switch

EV3 Flow Control (Orange)

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What does this program do?

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Program: SonarTest.ev3p

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EV3 Color Sensor• Percent Mode:

– 5% = lowest dark– 100% = very bright

• Reflected Light Mode: shines a red light; we are using this mode.

• The light can be turned off – detecting ambient light (surrounding light) – not used today

• The sensor may need to be Calibrated (see Bonus material)

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Display EV3 Color Sensor value

Program: DispLight.ev3p

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• On the parade track record color sensor values– On Black line: ____________– One the beige table: ___________– On the beige color masking tape: ___________

Test & Read Your Color Sensor Data

Zigzag Line following IdeaLeft side following Right side following

Line following using a Color Sensor

Mission 3:

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Simple Line Following Algorithm

27Q: Right side or Left side following?

Program: LineFlwZZ.ev3p

How and Where to start the robot?

B C On the line: OK

How and Where to start the robot?

B C

Right side of the line: OK

How and Where to start the robot?

B C

Lost… Left side of the line: NO!

Follow the Parade Route and stop when an object is sensed

Mission 4:

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Repeat the following forever:If sonar sensor detects an object

Stop!!!!!

OtherwiseFollow the black line

Line Following with STOP

Line Following with STOP

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Program: paradeZZ.ev3p

Multiple parallel programs – RoboParade with Speed Display

(every second)

Mission 5:

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RoboParade with Speed Display

Program: paradeZZspd.ev3p

Concurrently Run 3 Parallel Programs1) Repeat the following forever:

If sonar sensor detects an objectStop!!!!!

OtherwiseFollow the black line

2) Display the average speed3) Float operations with other motor(s)

Parade Program Concept

RoboParade with all functions

Mission 6:

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RoboParade with all functions Line Following With Stop

Motor on Float

Display Robot Speed

Program: paradZZall.ev3p

Calibration of the Color Sensor

Bonus Material 1:

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EV3 Color Sensor Calibration

Program: Calibrate.ev3p

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• On the parade track record color sensor values– On Black line: ____________– One the beige table: ___________– On the beige color masking tape: ___________

• Run the calibration program on the parade track and repeat measurements– On Black line: ____________– One the beige color table: ______________– On the beige color masking tape: ___________

Test & Read Your Color Sensor Data

robofest@LTU.edu

Little Robots, Big Missions

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Questions?