Hands-on Learning: Platforms to Teach Programming - Freescale

Hands-on Learning: Platforms to

Teach Programming

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Session sponsored by

Eric Gregori

[email protected]

• Eric Gregori is an Embedded Firmware Product Specialist at

Freescale Semiconductor. He is a robot enthusiast with over

15 years of embedded firmware design experience.

• His specialties are computer vision, artificial intelligence, and

programming for Windows® Embedded CE, Linux®, and

Android™ operating systems. Eric authored the Robot Vision

Toolkit, and developed the RobotSee Interpreter.

• Eric writes for Robot magazine (www.botmag.com), and has a

blog about Robotics and Embedded Systems

at: http://blogs.freescale.com/author/ericgregorifsl/



mailto:[email protected]

http://www.botmag.com/

http://blogs.freescale.com/author/ericgregorifsl/

My headshot




Session Description

• “I hear and I forget. I see and I remember. I do and I understand.” – Confucius.

People of all ages benefit from using interesting tools to teach complex concepts.

This presentation covers the tools Freescale uses for hands-on training on complex

topics, such as sensor programming, Computer Vision, Android programming, and

microcontrollers.

• The low-cost Freescale Robot ( FreeBot ) is a 4 Degrees Of Freedom walking

robot with touch sensors, and a 3-axis accelerometer. The robot is a sensor

programming training assistant, used in hands-on classes around the world. The

robot is upgradeable with a low-cost embedded Linux computer converting it into a

Linux/Android programming and Computer Vision training platform.

• The Freescale i.MX53 Quick Start Board is a inexpensive yet powerful embedded

Linux computer. Packing a whopping 1GHz ARM® Cortex™-A8 processor with 1GB

of RAM into a 3-inch by 3-inch package. The i.MX53 is used for Linux and Android

programming training.







How to Teach

Sensor Programming

• The best part of my job is conducting training

– Focus on Embedded Linux, Android and Sensor Software training

– Students range from master programmers to those that have not

programmed since college

• Added computer vision to robots with the Robot Vision Toolkit

– Open source project

– Simple programming language called RobotSee

• RobotSee is a great way to teach sensor programming!







WebcamsComputer Vision

Devices Supported by the

Robot Vision Toolkit

JoySticksGamePads

SpeechRecognitionMP3/WAV play

NeroSky™ MindsetBrain Interface

Walking Robots Rolling RobotsGPS ( NEMA ) Robot Arms







How to teach Sensor Programming

Now we had a language for sensor training that was easy to

learn but what about the platform?

The platform had to be:

1. Interactive

2. Interesting

3. Affordable

4. Unique

A walking robot would make a perfect sensor training platform!




The Freescale Sensor Trainer

1. Interactive• 12-channel touch sensor

• 3-axis accelerometer

• Plug-in sensors for expansion

• 4-RC servos

2. Interesting• It’s a walking robot!!!

3. Affordable• Only $199.00

4. Unique• A 4DOF walking robot with a 3-

axis accelerometer touch sensor

and 32-bit, 512K flash,64K RAM

microcontroller with built-in

debugger







Success• We did multiple sensor trainings using the robot and the

Robot Vision Toolkit. They were all very well received with

positive reviews.

• The training platform worked out so well that Freescale

decided to sell it. On April 4th, we will be releasing the Robot

platform for sale on the Freescale website at $199.00.

• The platform includes support for programming in RobotSee,

C, or C++. We are starting a community around the robot on

TowerGeeks.org.




Example Lab Slides




Lab 1 : Using the accel in 1D mode

• In this lab, only 1 channel of the accelerometer is used.

• The data is displayed using the graphics library in the robot

vision toolkit.




Graphics Language Extension

RobotSee

Graphics

Language Extension

winpen( width, r, g, b )winbmp( "filename", "copy_type", r, g, b )winline( pen, x1, y1, x2, y2, plane )winimg(bmp, x, y, plane)winbut( bmp, x,y )wineditline( handle, x1, y1, x2, y2, plane )wineditimg(bmp,x,y, plane )wineditbut( bmp )wingetbut()wingetmouse()winupdate( )

Hardware

Language Extension

servos( )leds( )usbopen()readtouch( )readaccel( )readsensors( )iicwrite( )iicread( )spiwrite( )spiread( )




X

z

Y

Y – Axis of Accel

Z –

Axis

of A

cce

l




Graphics Keywords• winpen( width, r, g, b ) // Create a pen of a specific width and color• winbmp( "path_filename", "copy_type", r, g, b ) // Create a image from a bitmap• winline( pen, x1, y1, x2, y2, plane ) // draw a new line from xy1 to xy2• winimg( bmp, x, y, plane ) // display a new image at x,y• winbut( bmp, x,y ) // display a button using a bitmap at x,y• wineditline( handle, x1, y1, x2, y2, plane ) // modify a lines properties• wineditimg( bmp, x, y, plane ) // modify a images properties• wineditbut( bmp ) // modify a buttons properties• wingetbut() // get a button click event from the queue• wingetmouse() // get last mouse click x,y,button info• winupdate( ) // update the window with current changes




Lab 2: Balancing on 1 Leg

using 2 Channels

• In this lab, 2 channels of the accelerometer are used and

combined using trigonometry into a vector. The resulting

vector is used in a closed loop control algorithm to make the

robot balance on 1 leg.

• The data is plotted in real-time using the Robot Vision Toolkits

data plotter.




Measuring Roll using the Y and Z

axisX

z

accel

Y

Z

Y

Gravity

SOHCAHTOA

Tan = opp/adj

Tan(a) = Y/Z

a

Z^2+Y^2 = 1g




Lean to One Side

// p10=leftankle, p9=lefthip, p8=rightankle, p7=righthip

gosub(guimove,dump,leftankle=136,lefthip=128,rightankle=118,righthip=117)

print( "\nLeaning Right" )





soundplay( "WavFiles\playgames.wav" )

for( temp = 25 )

faceled = rand( 0, 7 )

gosub( ledtalk, dump )

delay( 100 )

next( temp = temp - 1, temp > 0 )




Take a calibration reading- this will be your setpointgosub( calcangle, calibrate )

calcangle:

local( decimal )

local( whole )

local( ltemp )

local( ax )

local( ay )

local( az )

readaccel( ax, ay, az )

if( ax & 0x80 ); ax = ax - 0x100; endif()

if( ay & 0x80 ); ay = ay - 0x100; endif()

if( az & 0x80 ); az = az - 0x100; endif()

print( "\n x = ", ax, " y = ", ay, " z = ", az )

ltemp = atan( 1000, az, ay )

if( az<0 && ay<0 ); ltemp+=180000; endif()

if( az<0 && ay>0 ); ltemp+=180000; endif()

if( az>0 && ay<0 ); ltemp+=360000; endif()

if( ay == 0 ); ltemp = 0; endif()

if( az == 0 ); ltemp = 270000; endif()

whole = ltemp/1000

decimal = ltemp

decimal -= whole*1000

decimal = abs( decimal )

print( " = ", whole, ".", decimal, " degrees" )

return( ltemp )




Closeloop control servo around

the setpointinfloop:

rate = 10

gosub( calcangle, angle )

error = calibrate/10000

error -= angle/10000

if( error > 0 ); rightankle += 1; endif()

if( error < 0 ); rightankle -= 1; endif()

print( " error = ", error )

if( rightankle < 85 ); rightankle = 85; endif()

if( rightankle > 110 ); rightankle = 110; endif()

if( rightankle > 90 ); leftankle = 120; endif()

if( rightankle < 90 ); leftankle = 90; endif()

print( " right = ", rightankle, " left = ", leftankle )

gosub(guimove,dump)

goto( infloop )




Plotting Calibrate and Error




Play Video

• http://www.youtube.com/watch?v=aS_KxpGbPaw

http://www.youtube.com/watch?v=aS_KxpGbPaw

Chumby Walking Robot Demo




Play Video

• play video

Picture.avi

Linux and Android Training

• A hands-on class is most effective when the attendees get to

take the labs home with them after the class.

• For years I have been teaching embedded Linux

programming on systems that cost thousands of dollars.

• The number one request from students ( especially college

students ) was the availability of low-cost tools.

• The i.MX53 is a low-cost ( $149.00 ) high performance

embedded Linux development system.




Do all the training on the

development system, then take it

home with you!!




Easy to use tools actually get used

The Problem:

• Many development boards are incomplete.

• When someone purchases a training tool, they want the open-

box-experience to be as trivial as possible.

• They want something that will let them concentrate on the

training.

The Solution:

• The i.MX53 Quick Start Board boot to Ubuntu out of the box.

• No extra cables to buy, no host computer required

• Just add a USB mouse, keyboard, and VGA monitor

• www.freescale.com/imxquickstart




http://www.freescale.com/imxquickstart

Just as important as the training

is the material available after the

training







Thank YouPlease join us in the networking lounge for a

Q&A Chat

And please do not forget to visit the Freescale Booth

www.freescale.com/robotics




http://www.freescale.com/robotics

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Hands-on Learning: Platforms to Teach Programming - Freescale