beanz Magazine April 2018

Kids, Code, and Computer Science Modding Out with Minecraft

d n e i r F d e t s u r T A ant t s i s As l a t i Dig n w rO u o Y Build

Unbreakable!

The Story of the Coolest Secret Code Ever Rubik's Cube Secrets: Solve It Once and for All! April 2018

$6.00$6.00 USD

beanz magazine April 2018 : Volume 5 Issue 5 Issue 35 (online) & 20 (print) ISSN: 2573-3966 (online) ISSN: 2573-3958 (print) beanz Magazine© is published bi-monthly, six times a year, online at http://beanzmag.com and in print.

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Published by Owl Hill Media, LLC 378 Eastwood Rd, Woodmere, NY 11598 Email: hello@beanzmag.com Phone: (646) 553-3390

Publisher’s Note Welcome to this April issue!

Recently, my family and friends have bought digital assistants like Amazon Echo or Google Assistant. Their experiences are different enough—one banished the Echo to his garage, another bought a second one because it was so useful, a third has connected the assistant to her lights, coffee machine, and more.

I asked one of our writers to see if there’s an open source digital assistant. With it, you'd get privacy as well as useful technology.

You’ll see it’s our first story this issue.

Digital assistants also shine a light on technology and privacy issues. Apple, for example, stores your voice recordings but encrypts them so they can’t know what you said. And Amazon, Google, and Apple let you delete your voice recordings, if you know how (see the tidbitz article for details). So, yes, buying an offthe-shelf digital assistant puts a surveillance device in your home.

But you do have some control. Also, there is at least one open source option to explore if you’re motivated.

Other stories in this issue are equally interesting and fun. There are some awesome summer STEM camps to consider, a Scratch project that explores how birds flock, a Navajo code talker story, and one on traveling the world from school or home with Google Expeditions. Plus Minecraft modding and how to solve a Rubik’s Cube. For teachers, an essay about Kinesthetic Computer Science.

Hope you enjoy reading this issue and try some of the projects!

POSTMASTER: Send address changes to Owl Hill Media, LLC, 378 Eastwood Rd, Woodmere, NY 11598.

Periodicals postage paid at Woodmere, NY and other mailing offices.

Copyright Owl Hill Media, LLC with all rights reserved except as noted. Flickr images are copyright their creators, as noted with each story both online and in print.

Publisher/Editor/Webmaster: Tim Slavin Staff Writers: Simon Batt, Patricia Foster, Bonnie Roskes, Clarissa Littler, Jennifer Newell, Les Pounder, Paul Seal, Erin Winnick, Tim Slavin Contributors: David Dodge, Jay Silver, Jeremy Kubica, Colleen Graves, Daniel Fenjves, Ali Hagen, Emeline Swanson, Jean-Francois Nguyen, Madeleine Slavin, Tim McGuigan Back Office Magic: Wendy Garrison Copy Editors: Madeleine Slavin, Derek Lanuto Art Director: Kelley Lanuto Webmistress: Patricia Foster COVER IMAGE: KEN REID ON UNSPLASH

Tim Slavin Publisher beanz Magazine beanz magazine (as Kids, Code, and Computer Science magazine, our earlier title) is a winner

Our Mission

of Parents’ Choice, Tillywig, and Academics’ Choice awards: http://beanzmag.com/awards

beanz magazine is a bi-monthly online and print magazine about learning to code, computer science, and how we use technology in our daily lives.

The magazine includes hard-to-find information, for example, a list of 40+ programming languages for education, coding schools, summer tech camps, and more.

While the magazine is written to help kids ages 8 and older learn about programming and computer science, many readers and subscribers are parents, teachers, and librarians who use the articles to learn alongside their young kids, students, or library patrons. The magazine strives to provide easy to understand how-to information, with a bit of quirky fun. Subscribers support the magazine. There is no advertising to distract readers.

The magazine explores these topics: Basics of programming and where to learn more, Problem solving and collaboration, Mathematical foundations of computing and computer science, Computational thinking, Recognizing and selecting computer devices, and the Community, global, and ethical impacts of technology.

April 2018

2 9

Cover Story Electronics A Trusted (and Helpful!)

Friend

Notebook Save the Drama for the Llama

ALAN LEVINE, FLICKR

6 8 10 12 14 15

Sketch Up Puzzle Me This!

Show and Tell It's All in How You Look at It Secret Codes Cover Story Unbreakable!

Coding Let'ssssss Write a Game Scratch Boids: AI in Flight Minecraft Cover Story Modding Out

tidbitz

24 Turn Up the Heat 24 Erase That!

24 New App: Ink to Code 25 If You Want It Done Right, You Have to Do It Yourself 25 Ethically Speaking...

25 One Man's Toy Is Another Man's Treasure 25 Using LiDAR on a Dig

16 17 18 19 20 22

Languages Seeking Clojure Notebook Robofrog Goes a'Courtin' Puzzles Cover Story Rubik's Secrets Coding Coding Regex Electronics Intruder Alert!

Robotics Sphero in Literature Class

28

Notebook 6 Great STEM Summer Camp Options

TECH I.R.L 26 Hop to It 26 Park It Here

29

ParentTeacher Corner Kinesthetic Computer Science

contents

advanced

intermediate

beginner

scribe b u s / m ag.co m z n a e b http://

Electronics

2

d d n e e t i r s F u r ) ! l T u f A p l e H d n (a

BY LES POUNDER

“Siri, what is the highest mountain in the world?”

“Alexa, order some printer ink.”

“Ok Google play some music.”

Digital assistants (also called smart speakers) listen to what you say, then send that information off to a remote server, where it is processed before sending a response back to you.

Why do Apple, Amazon, and Google provide these services?

Typically, they get data from our enquiries. Amazon knows what products we buy and what music we like, while Google learns about how we live, our calendars, and our search histories. These devices offer a great service, and they can make our lives easier.

However, some people feel uncomfortable letting

companies listen in on everything they’re doing in their homes or apartments. And these companies remember and keep your voice recordings long after they’re processed. We can’t control how our voices are used.

Can we make our own smart speaker that offers a similar set of features, but whose memory is entirely in our control? Yes! Introducing the Mycroft project.

It offers a similar experience to other digital assistants, but with a much more open approach to data. Mycroft devices can be purchased via Kickstarter (crowd funding) or we can make our own using a Raspberry Pi 3.

This device is called a Picroft and it has all the functionality found in the Google, Apple, and

Amazon speakers. However, we will have much more control over how things work. For this project you will need: • Raspberry Pi 3 • 8GB micro SD card • USB microphone • Analog speaker (3.5mm speaker plug) • Internet connection • (Ethernet and WiFi) • A computer running Windows/Mac or Linux The Raspberry Pi 3 assumes you have it set up with, for example, an HDMI cable to connect to a monitor, a power cord, keyboard, mouse, and have a micro SD card reader. See the back cover of this magazine for the article URL with links and KidsCodeCS.com/pi-start to get the official Pi setup guide.

Setting up Mycroft

To use Picroft, download a copy of their open source software image. From the Mycroft website https://mycroft.ai/ click on CONTINUED, PAGE 4

her weat da “The Ugan r o f t as in..." forec ke ra i l s k loo

All we need to make our own digital assistant is a Raspberry Pi 3, a speaker, and a USB microphone

Setting up WiFi When you finish this project, the Picroft device will be tethered to the Internet via an Ethernet cable.

However, you can remove one cable from the project.

The Raspberry Pi 3 has a built-in WiFi adapter that you can use to connect to the Internet, but you do not have a graphical tool to help connect. So you'll need to use the Terminal to edit a file called wpa_ supplicant.conf which contains the necessary configuration for the WiFi. First, make a copy of the file, just in case something goes wrong.

3

the s ' t a “Wh ast c e r o her f t a e w a?" d n a g for U

STEVEN STRAITON, FLICKR

Enter into the terminal: STEVEN STRAITON, FLICKR sudo cp /etc/wpa_supplicant/wpa_supplicant.conf /etc/wpa_supplicant/wpa_supplicant.conf.backup Now we can edit the original file. sudo nano /etc/wpa_supplicant/wpa_supplicant.conf In the original file we can delete everything and start fresh. All we need to enter in the file is as follows. You will need to replace the ssid and psk with the WiFi access point, and the password used to get online. network={ ssid="YOUR WIFI ACCESS POINT NAME" psk="THE ACCESS POINT PASSWORD" } To save the edit, press CTRL + O, then Enter. And to exit press CTRL + X. To ensure that these changes have been written we need to reboot the system. sudo reboot Now go ahead and talk to Mycroft!

4

CONTINUED FROM PAGE 2

Download, then in the next screen look for the Raspberry Pi logo.

Click on it to download the image.

Problems? If so, try this alternative link: https://github.com/ MycroftAI/enclosure-picroft/.

With the software image downloaded you now need to write that image to a blank SD card, and the best tool for the job is called Etcher (https://etcher.io/) as it provides a consistent and easy to use interface across Windows, Mac and Linux platforms.

Once Etcher has finished, there is an additional step: go to the BOOT partition of the micro SD card. This will be mounted in your file manager. Inside the BOOT partition create a new file simply called ssh. This will enable you to remotely connect to your Picroft using SSH. You can now eject the micro SD card from your computer and insert it into your Raspberry Pi 3.

Then connect to your Pi the USB microphone, the 3.5mm speaker plug, an Ethernet connection, and finally the micro USB power connection. But don’t turn on the Pi’s power just yet!

Once signed up, add your Picroft device using the Devices menu at the top of the screen.

Now turn on the power to your Picroft device and wait for it to boot. Picroft will go through a process of updating its software, and then it will tell you that it is connected to the Internet, but it needs to give you a six digit code to connect this device with your Mycroft account.

Create an account

Download Etcher. Run the downloaded file to install and open Etcher.

To use Etcher, follow a three step process. First, tell it where your software image is (should be in your Downloads folder). Next, tell Etcher where to write the image, so insert your blank micro SD card and select the correct drive. Lastly, Flash the image onto the card. This step may take time, but ensure that it completes correctly before moving onwards.

In order to use Mycroft / Picroft, first you need an account. Go to https://mycroft.ai/ and click on LOG IN. It will open up a new page where you can sign up.

Got Skills?

You can add some extra abilities to the device by doing a little work with the terminal software.

Skills are how Mycroft learns new abilities. To teach Mycroft new skills, log in to the Picroft device using SSH from your computer.

You'll need to know the IP address of Picroft on your network, so ask Mycroft: “Hey Mycroft what is your IP address?”

Remember to write down your IP address as you'll need it later!

For Windows users, download PuTTY https://portableapps.com/ apps/internet/putty_portable

Picroft will speak the code. Enter that code into the Registration Code section of the Devices page on their website. Then, tell the

and then install. Open PuTTY and look for the Host Name (or IP address) section, then type in the IP address of Picroft followed by pressing Open. You'll be asked for the username which is pi and the password is mycroft.

Linux and Mac users will need to open a Terminal, and type in ssh pi@<IP ADDRESS OF PICROFT> Again, the password is mycroft.

Now issue commands directly on the Picroft device.

The first screen is the Mycroft

page that we have a Picroft device, give it a name, and tell the page more about the device. In this case it is "on my desk."

When ready, click on OK, LET’s PAIR and after about 1-2 minutes your Picroft device will start talking about what it can do. So let's try it out: ask your Picroft what the weather is like where you live. For example: “Hey Mycroft, what is the weather like in Des Moines, Iowa?”

You'll hear Mycroft explain the weather in your hometown! Your Picroft device works!

You can also control the volume at which Mycroft speaks, by setting the value between 0 and 10 as so.

“Hey Mycroft volume 5.”

Handy, because sometimes he can get a little too loud.

You’ve now got a smart speaker that you control. Mycroft claims voice recordings are deleted after they’re processed and that no third party handles your recordings. Your privacy is secure. Their software also is open source which means anyone can see how their code works.

You've successfully created your own digital assistant that will respond to your commands and act accordingly. Along the way

CLI (Command Line Interface), used to monitor and debug Mycroft. For now you don't need it, so press CTRL + C to close the CLI. You're now in the Linux terminal, and in here you can control every aspect of the Picroft device. To see what skills you can teach your Picroft, type the command, and press Enter. msm list This will list all of the skills available for use. For now let's choose a skill called Skill-Dice.

Install it from the terminal using the

you learned that digital assistants respond to commands from the user, convert this audio to text and then use that text to launch skills that are preloaded into the device, or to run searches on the Internet. This means that your data is analyzed by a remote device, and a response is delivered to us in a timely manner.

You also learned that while this is still not a perfect solution when compared to Amazon or Google’s projects, it is a viable open source tool that does not invade our privacy.

Taking this further, you can write your own skills for Mycroft (see below in green bar).

Skills are written in Python and you are free to look at the code behind the skills we used in this tutorial, and there is an extensive documentation project supporting the Mycroft project https://mycroft.ai/ documentation/.

And as always, check out the link for this story on the back cover of this issue for much more! b

following command. msm install skill-dice This will take a while to install, but when completed control of the terminal will be handed back to you. To start the skill ask Mycroft to roll one, six sided dice.

“Hey Mycroft, roll 1d6.”

Mycroft will tell us what the roll achieved. If you are an avid role player/board game fan then this app can be used to roll the dice in your favorite game. For example a role player may wish to roll three six sided dice:

t, ycrof M y “He is the what t onten c c i r ?" calo arrot c s i h of t

ERIC KILBY, FLICKR

“Hey Mycroft roll 3d6.”

Or roll a D20: “Hey Mycroft roll 1d20.”

Just remember to state the number of dice then the number of sides that the dice have.

You are now able to install other skills and use them directly with Mycroft. Try the Internet Radio skill. msm install internet-radio and read more about this skill via their webpage https://github.com/ normandmickey/skill-internetradio.

5

6

SketchUp

BY BONNIE ROSKES

If you haven’t completed the previous SketchUp projects in this magazine, go to www.my.sketchup. com for the modeling application: This is the web-based version which we'll use here.

In this project, we’ll create a jigsaw puzzle from an image. I'm using an image of candy. You can use any image; just make sure it’s saved on your computer.

Go to the SketchUp page and launch your modeling session, and you'll see: a man (Josh) standing on the ground with axis lines around him. The red and green axes are on the ground, blue is for the vertical direction. There’s no need to have Josh there, so click the Eraser icon or press the E shortcut. Click on any edge of Josh to erase him.

The puzzle will lie flat "on the “ground,” so switch to a bird’s eye view—looking straight down at the ground from above. Click the Views icon on the right.

Click the icon that looks like the top of a house.

Next, bring in the image. Click the Folder icon, top left, then choose Insert. Because the image is stored on your computer, click the computer icon.

Go to where you have your image and choose that file to insert.

Then SketchUp will ask how you want it inserted: as a material or an image. Materials are used to paint faces that already exist in a model, and we don’t have any faces yet. So choose Image.

Click the first corner, then move the mouse to get the image to the size you want, and click the second corner. (The size doesn’t matter; you can zoom in and out.)

An image in SketchUp isn’t really useful, but we can make an image into something usable. Right-click on the image and choose Explode.

Now we have a regular SketchUp face, with four edges, painted with the candy image.

up the face while the picture itself isn’t showing. To change the model’s style (the way the model is displayed), click the Styles icon.

In the Styles window, click the magnifying glass icon to get the list of standard styles. Then, open the “Straight Lines” category, because these styles have blank faces. Choose any style.

Now the face is plain white, surrounded by a white background.

Press the L icon for the Line tool. Draw one line that goes from the top edge of the face to the bottom. You can make your lines perfectly vertical and horizontal, or make them slightly slanted.

Complete the lines that divide the face vertically. Then add some that divide in the horizontal direction.

This is the view you should see:

Now that we have a face, that face can be divided up into puzzle pieces. But it’s a lot easier to break

Now you’re probably thinking it’s time to move these pieces around. But not so fast—there are

7

Right-click on the selected face and choose Make Group.

Now activate Move again (M key) and move your cursor over the new group.

What’s highlighted now is the entire group, not just the face that was highlighted before.

The little red “plus” signs are used to rotate the group. We don’t want to do that (unless you want a really hard puzzle).

Click the piece to start the move, slide it away from the rest of the puzzle, and click again to

“drop” the piece.

Now you know the steps needed to make each piece movable: Activate Select and double-click the next piece. Make that piece a group.

Repeat for each piece. Then, when each piece is a group, activate Move and slide each one away. Here are my scrambled puzzle pieces:

Now, change the style back, so that the image becomes visible again. Go back to the Styles window, and click the House icon. This shows a list of all styles in your model.

The one we want is the original style—the one with colored faces and not blank ones.

Now, start to solve! When solving the puzzle, just keep the Move tool active the whole time. Find two pieces whose edges line up:

Click a corner to start the move . .

.. . . and join that corner to the corner where it lines up.

Keep moving pieces, one by one, until all your candies are unscrambled.

You can try this project with puzzle pieces of all different shapes.

You can use arcs instead of (or in addition to) lines, or try making actual jigsaw shapes with little arc bump-outs.

For a really neat version of this, use an image that has a written message for a friend. Scramble the pieces and have your friend solve for the message. b

cool beanz!

RAWDONFOX, FLICKR

a few more steps needed before this. If you tried to move one of the pieces now, all of its neighboring pictures will be dragged along with it. So to make these pieces able to move individually, each piece has to be a group. In SketchUp, groups are used for several things. In this case, a group will “wrap” each piece as its own object, not connected to any objects around it. For our first group, active the Select tool (press the Spacebar), then double-click the first little piece. This selects both the face and its four edges.

Show and Tell

8

BY PATRICIA FOSTER

It's All in How You Look at It Do you remember what you ate for dinner 17 days ago? Or what color shirt you wore? Probably not. For most people, the details of average days blur together.

But when you go on a trip, every sensation is etched into your mind.

Now, which do you find easier to remember: “collywobbles” or “763927501827”? Even if you have no idea what “collywobbles” means (it’s a fancy term for bellyache), you’ll probably pick the word. Yet both have 12 characters. Why is the word easier to remember?

Both exercises show us the way we learn best: when information is meaningful, and when all of our senses are engaged. Yet most schools are unable to bring all their students on a trip, much less an expedition to the International Space Station! Or do they?

In 2015, Google launched a free app to let students travel the world through their smartphones. A device using Google Expeditions is inserted into a cardboard viewer to create

“The Great Wall of China” by AirPano (student’s device)

Screenshot from “Career Expedition: Paleontologist, Mark Norell” by the Starfish Media Group (teacher’s device)

a virtual reality (VR) headset. The app immerses you in 360° photos.

When you move your head, the image moves with you.

Teachers lead the expedition from their iPads. Hundreds of excursions are available in all subjects. There are also “career expeditions” where students can get a feel for different careers. Each scene offers educational snippets for all levels.

The technology is simple. To understand how it works, hold up your index finger in front of your nose. Close your right eye. Now close your left eye as you open your right. See how your finger shifts right and left? Your eyes are a few centimeters apart. Each one receives a different “picture” of the world. Your brain puts the two pictures together to estimate depth.

This is stereoscopic vision.

Google Expeditions uses stereoscopy to trick your brain.

Outside the cardboard, the phone displays two slightly different

images side by side. The cardboard isolates each image. This prevents you from peeking, which would make your brain aware of the trick.

Official Google Cardboard headsets can be purchased for $20, or scavenged from the internet for even less. You can build your own.

Cardboard is easy to scrounge up, and Google provides an official template for the headset. The magnets and biconvex lenses can be purchased online or removed from binoculars.

Are Google Expeditions better than a textbook or a movie?

Absolutely. Are they a substitute for being there in person? No. Critics point out that the excursions are still just static photos. They’re engaging, but they don’t allow you to interact with your environment. The technology can be glitchy. Our brains are experts at telling the difference between real and virtual.

If the images load too slowly, or don’t respond exactly to our head movements, it can cause VR sickness. Additionally, Google Expeditions requires each student to have access to a smartphone.

But the potential for education is great. The Google Cardboard viewer is the first VR headset that’s affordable and scalable for schools.

As VR matures, apps will become more interactive. And ultimately, visiting the International Space Station—even through a phone screen—tops any textbook or documentary. b

Llamas are strange creatures: part sheep, horse, and maybe giraffe. Recently, a friend of mine who knits visited a farm that sold skeins of yarn made from their llamas' wool. I wanted to text her a llama emoji—only to discover there are tons of different smiley faces but no llamas!

Naturally, I wanted to know the reason. It’s an odd oversight. But I learned that the very first llama emoji will appear in the summer and fall of 2018, as part of the eleventh set of emojis released.

Emoji characters are suggested by a wide range of people, including everyday people like you and me, then accepted or rejected or, like the llama, delayed.

Computers treat emojis the same as other standard characters, for example, the upper case letter A or punctuation marks. Once accepted as a standard character, an emoji is created by software companies that provide emojis along with letters and other characters. Emojis on an Android phone may look different than on an Apple phone which, in turn, may look different in a Windows email application.

Did you know you can sponsor your favorite emoji and put a badge on your website to show your emoji pride? It’s pricey, $100 is the minimum amount, but for people with spare money and a sense of fun, it’s a good way to support the standards committee that organizes the process used to create emojis.

If you like llamas, be sure

to look for the llama emoji this summer and fall. You can text your friends and tell them to save their drama for the llama. With a llama emoji, of course. b

9

Notebook

Save the Drama for the Llama

BY TIM SLAVIN

, my y l l a “Fin oji!" m e own ERIC KILBY, FLICKR

Secret Codes

10

l b a k a e r b n U

BY SIMON BATT

For the past few issues, we’ve been covering very logical ciphers.

These have used an encryption and decryption method that follows a strict set of rules. Just like programming, these ciphers have a logical means of being constructed, and are essentially a logic puzzle.

In the same way, a cipher that’s established on hard logic can be disassembled by working out the logic the cipher is built on. This was the job of many decryption computers over the course of history, such as the Enigma machine.

This is because computers are very, very good at performing intensive logical operations quickly.

It may take you a long time to calculate what 38 times 65 is, but a calculator will tell you instantly that the answer is 2470. This speed of calculation makes computers a great ally when trying to decrypt a code’s logic. But what if a code isn’t based off of hard logic, but instead uses

creativity as its basis? A computer can do math problems very easily, but ask it to draw a picture and it will do a very bad job!

This was the case of the Navajo Code, a cipher used during World War II that was never deciphered.

The reason for this was simple; the code itself was based on creative interpretation of objects rather than a straight logical code.

The code was based on the Navajo language, which doesn’t use a writing system. Very few people in the world knew how to speak it.

It obfuscated itself further by using creative definitions for different aspects of war. For example, they didn’t call a cruiser a ‘cruiser’ in Navajo language. Instead, they called it a ‘small whale’. Even if the enemy managed to decipher the Navajo language, all they’d hear is people talking about whales!

The Navajo code was so strong, even native Navajo speakers unfamiliar with the code couldn’t crack it. It may seem strange that a

The Navajo Code Talkers Association, Inc. at the Memorial Amphitheater July 6, 1983.

U.S. ARMY PHOTOGRAPH, FLICKR

fluent Navajo speaker would struggle with this code, but there are English ciphers similar to Navajo that show how hard it is.

If you overhear someone saying ‘move you bacon up the apples, wash your boat, and go to Uncle Ted,’ you’re hearing someone speaking Cockney Rhyming Slang.

This verbal code takes a word (stairs), assigns a 2-3 word rhyming phrase to it (apples and pears = stairs), then drops the rhyming part and uses the rest (apples). Examples include ‘bacon and eggs’ (legs), ‘boat race’ (face) and ‘Uncle Ted’ (bed). Now you can decipher the strange sentence at the start of this section!

You can see how hard it is to decipher a code based on your own language, so you can imagine how hard it can be for a computer to do it. In fact, a computer never did manage to do it. The Navajo code went unbroken until the US Army declassified the dictionary for all to see. This shows that, if you want to make an unbreakable cipher, sometimes you don’t need to base it on dizzying levels of logic; a bit of creativity will sometimes do the trick!

If you want to have fun with these unique ciphers, why not give one a try? Navajo code is militarybased, so you may struggle to talk to someone in it. Cockney Rhyming Slang, however, is based on daily activities, so you might have better luck with that. Even better, why not make a creative cipher yourself and confuse anyone trying to overhear your conversations? Give it a shot! b

! e l

11

The Navajo Code Talker Memorial in Window Rock, AZ

Navajo Code Talkers Marine Corps Cpl. Henry Bake, Jr. and Pfc. George H. Kirk use a portable radio near enemy lines to communicate with fellow Marines in December 1943

RON COGSWELL, FLICKR

ROBERT SULLIVAN, FLICKR

Coding

12

Let'ssssss Write

BY CLARISSA LITTLER

In the last issue, I talked about my experience in PyWeek, a weeklong game jam created specifically with Python and the PyGame library.

In this issue, we'll talk more about PyGame itself.

PyGame is a fairly old library, but one that's still being used and updated because it's an easy way to write your own game engines in Python.

A game engine is most of the guts of the game, and is the code for things like physics, motion controls, or handling keypresses, mouse movement, and using a controller.

PHOTO BY DAVID CLODE ON UNSPLASH

Games writing is a spectrum: on one end you don't necessarily need to do programming to make a game (GameMaker, for example). On the other end you write ALL the code to • talk to the graphics hardware to be able to put colors in specific pixels • load images from files and turn it into something that can be displayed on the screen • ask the operating system for keyboard/mouse/controller inputs • handle refreshing the screen many times a second etc.

Most methods of writing games fall in the middle. Unity and Godot

are more towards the GameMaker end, while PyGame is closer to the full DIY way of making games.

In PyGame, you have a lot of freedom. PyGame gives you the code that handles how to use sprites, display images, handle simple collisions, receive inputs from the player, control frame rate, and load music and sound effects.

Almost everything else is left to you, the game writer, to develop!

You can write your own physics or combat engines and develop your own ways of handling levels or scenes.

If you've used Scratch before, you've probably run up against times that you've thought "I don't like the way Scratch does this." Personally, I

a Game wish I could send a message to just a single sprite in Scratch. Well, the less "opinionated" a framework is, in other words the less it decides for you, the less likely you are to have moments like that.

Using a less opinionated framework like PyGame means you're more likely to be able to do things exactly the way you want them. On the other hand, you're probably going to be writing a lot more code than in something like Scratch or Gamemaker.

So how does PyGame work?

Well, if you have Python installed on your computer then getting PyGame is as simple as opening up a command line prompt and running

python -m pip install pygame PyGame is also very easy to get started. Here's an example that opens a window and then displays the text you type. (See code in box below) This introduces a few different important concepts in PyGame.

First, that you need to actually write a "game loop". It may not look like the one above, but you'll always need some kind of while-loop that is the top level control of the game.

Second, in PyGame you're never actually drawing to your real screen, but rather to a surface which is a data structure. It holds records of what goes in each pixel of the window or screen the PyGame

import pygame pygame.init() size = [600,480] screen = pygame.display.set_mode(size) done = False text = "" alphabet = "abcdefghijklmnopqrstuvwxzy" while not done: for event in pygame.event.get():

if event.type == pygame.QUIT:

done = True

elif event.type == pygame.KEYDOWN:

key = pygame.key.name(event.key).lower()

if key in alphabet:

text = text + key

elif event.key == pygame.K_BACKSPACE:

text = text[0:len(text)-1] screen.fill((255,255,255)) font = pygame.font.SysFont('Arial', 25) textSurface = font.render(text,True,(0,0,0)) screen.blit(textSurface,[100,100]) pygame.display.flip()

13

program will be displayed on. In PyGame you'll be dealing with surfaces constantly. Sprites will have surfaces holding their current frame of animation. You write text to a surface, like in the above example.

Finally, you have the surface that represents the window the game is being displayed on. Combining surfaces is called blitting.

When you're ready to display the next frame of the game you need to "flip" the display. This means you take all that data that you've stored up for each pixel and plop it on the screen in one go.

That might seem a bit elaborate to draw to the screen.

But drawing to the screen with any game-making library is like this. PyGame, since it's more low level than something like Unity, just makes the real process of rendering each frame a lot more obvious. Whether or not that's a good thing is up to you!

Finally, the way you make interactive games is by using PyGame's event system. If you're coming from something like Scratch, this might be the most familiar-looking part. PyGame takes all the data from your mouse, your keyboard, or your controllers and organizes it into a stream of events.

Every time your game loop runs, you need to check what events happened and act accordingly.

Was a key pressed? Was a mouse moved? How much was it moved?

What key was pressed? These are the kinds of things you can check with the events in PyGame.

With just these few concepts in mind, you're ready to check out the link on the back cover of this issue for lots more on PyGame! b

Scratch

14

Boids: AI in Flight

BY CLARISSA LITTLER

We've done a lot of games in Scratch, but in this issue let's talk about a cool little bit of classic AI: Boids!

Boids is a model of how birds flock, done in a way that is simple and yet manages to replicate how birds really move. Invented back in 1986 by Craig Reynolds, Boids only has a few simple rules: 1. Each Boid steers to move

towards the center of the flock 2. Each Boid adjusts its flight to be

closer to the average direction

and speed of all the other Boids 3. Each Boid steers so that it isn't

too close to its neighbors These three rules provide a competing tension of forces that determines the flock's behavior.

What's the idea behind these rules?

The first one tells us that a flock should try to be coherent: birds of a feather flock together, as the old saying goes.

The best way to ensure that is to steer towards the center of the flock.

But if that's the only rule then they'd all eventually fly towards a single point and then fly back and forth around the center. Not good!

No, instead, you want them to keep flying in roughly the same direction. That's where the second rule comes in. Every Boid will look at where the flock is headed and turn a little bit that way.

The last rule recognizes that Boids can't fly too close together, because they'd be slapping each other with their wings and making it impossible to fly. So the third rule is just a way to keep the Boids from overlapping unnaturally.

You might be wondering how good could a simple algorithm like this be? Well, Boidsâ&#x20AC;&#x201D;or variations of themâ&#x20AC;&#x201D;are frequently used when

games or animations need to draw flocks. If you've ever seen the movie Jurassic Park, the CG for the Gallimimus "flock" was done with a Boids-like algorithm!

Here's how to write an implementation of Boids in Scratch.

This is probably not the kind of Scratch program you're used to writing. We'll use lists and messages extensively to make sure that we're calculating all the averages correctly.

We'll be roughly following the presentation found here: http:// www.vergenet.net/~conrad/boids/ pseudocode.html, but we're going to adjust a few things to fit Scratch.

We're also going to add a fourth rule: the Boids will turn slightly towards the mouse as they move. For the convenience of using Scratch, with its fairly small stage, we'll also have the Boids reflect off of the edges of the screen.

The basic idea of our program is that we're going to need to keep track of the average of the x-position, y-position, x-velocity, and y-velocity in order to calculate corrections to each Boid's flight.

To calculate the average for each piece of data, we use lists for each of these four attributes and have an entry for each individual Boid.

There will be a lot of parameters we'll want to tweak: factors that control how much each of the main rules contribute to the steering of the Boids. This means making a lot of variables so you can play with them and figure out what works best. I have variables for the strength of each rule 1-4, the speed of the Boids, and the number of Boids.

Try making this project for yourself first. Then I want to give at least a brief

outline of the bigger program to try: 1. Writing your main loop. This handles setting up your parameters, clearing the lists, making all the Boid clones, and handling the loop of calculating the averages you need to keep track of before telling the Boids to move again. (You don't want the averages to be recalculated until after all the Boids have moved.)

2. Writing the setup code for the Boids, which should set their initial positions and the direction they're flying. I did this in a randomized way.

3. Writing a loop that handles the movement for each Boid. You'll need to update the velocity and positions in all the lists you're tracking as the Boids move. Another important detail, that's actually left out in the implementation I linked to, is that you should make sure you normalize the velocity of the Boid so it doesn't get faster and faster.

On the back cover of this issue there's a link for this article that will bring you to many other sources of information, and will help explain the more advanced details. Check it out! b

For info on Scratch go to https://scratch.mit.edu

For info on Minecraft go to https://minecraft.net

Last issue, we talked about online servers and how to access them. If you gave it a try, you may have noticed that people were playing Minecraft in new ways. While the base Minecraft experience is about exploration and creating, you may have come across servers with special weapons, new game modes, and other custom content. This is done through what’s called modding.

Modding means you add onto or edit the game files in order to add new content.

Making a mod is tricky. If you’re not into coding, you may want to stay away from making your own mods. Downloading and installing other people’s mods is much easier! This allows you to extend your Minecraft experience without having to learn any coding.

You can find great Minecraft mods at Planet Minecraft, Minecraft Forum’s mod section, and Minecraft Mods. If you visit those sites, you may feel a little overwhelmed by all the choices.

Ask yourself what you want to mod, and find mods that are related to that.

When you play Minecraft, did you enjoy exploring the world around you? If so, look for mods that add new places to go. The Space Age mod is about making a rocket ship and going to the moon, so you’re bound to have great exploration there.

There are also mods that add new realms and dimensions for you to check out.

If you’re into combat, look up the many different weapons and attack methods you can add on.

Enjoy farming? There are plenty of crop and animal mods that will expand your farming realms. If you’d like your farm to look the part too, there are mods that add fences and gates to make your farm look beautiful.

If you're an inventor at heart, you’ll want mods that add extra machinery to the game. While redstone can be a lot of fun, look for mods that can implement steam and electricity for even more advanced technology.

Too much of a hassle to download, install, and get the mods working nicely together? Then consider a modpack. Modpacks are essentially big bundles of mods that are pre-constructed for the best experience. They’re usually based around a specific theme, so you know exactly what you’re getting with your download.

One of the better modpack websites is Curse Forge. The mods are sorted into different categories,

15

Minecraft

Modding Out

BY SIMON BATT

so you can easily choose where you want to focus. People looking for a fight may want the Adventure-based modpacks, while those who want to build fantastic machines will go with the Tech modpacks. These all install nicely using the Curse client.

Once you’ve played with mods a little bit, you may want to make your own. Even though they’re quite tricky, coding a mod for Minecraft can be a fun way to learn about creating game elements.

After all, all the main game is already made for you! To code for Minecraft mods, you’ll have to learn the Java language, and read tutorials to get an idea on what you need to do to code a mod.

Be careful where you download mods. Because of Minecraft’s popularity, some people upload virus-infected files in hopes that players will download them. Only download from trusted mod websites. Find mods that are wellrated to ensure the mods you’re getting do what they say they do! b MAGGICRAFT, FLICKR

Instant structure mod of a beach resort

Languages

16

BY CLARISSA LITTLER

Seeking Clojure Two issues ago (December 2017) we talked about Kotlin, a language that ran on the Java Virtual Machine (JVM). Languages built on top of the JVM have a couple of advantages.

The first is that it helps the language run on any platform that Java can run on. The second is that languages that use the JVM get access to all the library code that comes standard with Java: a large amount of prewritten code you're able to use.

Another concept is macros, which we introduced when talking about the Julia language in the last issue (February 2018). Macros are, essentially, code-that-writes-code.

Clojure is a language that runs on the JVM and has macros.

Clojure is a part of the Lisp family, a very old family of programming languages dating back to the 1950s!

The Lisps include a number of languages still in use today such as Common Lisp, Scheme, Racket, Emacs Lisp, Pico Lisp, and of course Clojure. Even Julia could be considered a part of the Lisp family.

All the Lisps have a very simple syntax, which makes them easy to learn, and easier to write macros.

This usually means Lisps have prefix syntax with lots and lots of parentheses. For example, in most Lisps, adding two numbers looks like (+ 2 3) instead of 2 + 3.

If you remember from the Julia story, there's a fun way you can estimate pi by using random number generation. The Clojure code for that program looks like (defn calcPi [n] (loop [timesLeft n hits 0] (let [x (- (rand) 0.5) y (- (rand) 0.5)] (if (= timesLeft 0) (double (/ (* 4 hits) n))

(if (<= (+ (* x x) (* y y)) 0.25) (recur (dec timesLeft) (inc hits)) (recur (dec timesLeft) hits)))))) (println (str "pi is approximately: " (calcPi 10000000))) Contrast this with our Python implementation from last time! import random numTimes = 10000000 hits = 0 for i in range(numTimes): x = random.random() - 0.5 y = random.random() - 0.5 if (x**2 + y**2) <= 0.25:

hits = hits + 1 print("pi is approximately: ", 4*hits/ numTimes) These look different because they're very different programs.

Clojure is opinionated about how you write your code: it wants you to write in a functional way that doesn't default to changing the contents of variables.

In Python, you're changing the variable "hits" again and again to count up. But in Clojure we're efficiently using recursion with the loop and recur constructs. This makes our Clojure solution like the following in Python: import random def calcPi(numTimes,n,hits=0): if n==0: return (4*hits/numTimes) else: x = random.random() - 0.5 y = random.random() - 0.5 if (x**2 + y**2) <= 0.25: calcPi(numTimes,n-1,hits+1) else: calcPi(numTimes,n-1,hits) def topCalcPi(numTimes): return

calcPi(numTimes,numTimes) print("pi is approximately: ", topCalcPi(1000000)) This will cause a runtime error because Python isn't built for these kind of efficient recursive solutions.

This is how different languages push you towards different styles of solution. If you've mostly used languages like Python or Java, then Clojure is going to nudge you to writing very different programs. If you've used Scheme, Racket, Haskell, or ML, then Clojure will be familiar.

You can get started with Clojure by first going to the Getting Started page on the main website (https://clojure. org/guides/getting_started). If you're on Windows instead of Mac or Linux, you'll want to start with Leinengen (https://leiningen.org/) to get set up.

Once you've got a working Clojure installation, the best way to learn it is with the Clojure Koans, available on GitHub (https://github.com/ functional-koans/clojure-koans).

The "Koans" style of language tutorials started years ago with the Ruby Koans. They're small, selfcontained programming puzzles.

These are progressive lessons: you learn a language bit-by-bit as you figure out how to write code that uses all the different features of the language. The Clojure Koans are a nice example of this tutorial genre.

Also, there's a closely related language: ClojureScript. It's almostbut-not-quite Clojure-compiling-toJavaScript. The differences between the two are summarized on the ClojureScript site (https://clojurescript. org/about/differences). This page will make sense once you're comfortable with Clojure.

Clojure shows what a modern and easily accessible Lisp can be! b

Robofrog Goes a'Courtin' A brown frog puffs out his vocal sac and he calls “whine.” To human ears, it isn’t that impressive. He sounds a bit like a laser in a video game. No one moves near him.

He tries again adding a deep grunt.

“Whine, chuck.” He still sits alone.

Finally he puffs up his chest and calls: “Whine, chuck, chuck.”

A female frog hops over and slides up next to him. After a moment, a scientist gently removes her from the pad. And another female is brought in for the test.

These female frogs may be disappointed in love, but Dr. Taylor is thrilled. The world’s first robotic túngara frog is hitting all the right notes. And the robotic frog's successes and failures in the dating world are not only telling scientists about froggy courtship, but a little bit about humans as well.

Dr. Taylor teaches at the Salisbury University in Maryland, and he studies frogs at the Smithsonian Tropical Research Center in Panama. He used to watch and listen as male frogs called. He wondered how the

female frog picked a mate from all the different calls.

Is it the frog’s vocal sac? Or the call itself? And even the call has two parts, which part is more important? And how is any of this connected to humans?

does not fill up his vocal sac. The females aren’t interested. Next, he inflates the vocal sac but doesn’t call. Again, the females have better things to do. But then he blows up his vocal sac, and gives a full call.

The females come hopping.

One thing at a time

Many scientists take problems apart so they are only working with one thing at a time. But how could Dr. Taylor do that with the frogs?

You can’t train a frog. You can’t ask the frog to only say part of the call.

Dr. Taylor and his colleague, Michael Ryan of the University of Texas, turned to engineers. "Can you build us a frog?" they asked.

The engineers accepted the challenge. First, they made a plastic frog. Then they added a balloon for a vocal sac. They needed speakers so the female frog could hear their robofrog's call. And they put in a computer to coordinate the different pieces.

Robofrog is ready for a date

Again and again he calls, but

A real male Tungara Frog “The females are paying attention to when they hear the call and when they see the sac move,” explains Dr. Taylor.

This was information the team acquired through these robofrog experiments. It was something no one knew before.

What’s more, says Dr. Taylor, other scientists are excited about the outcome because “humans do the same thing.” When we can’t quite hear people speaking, we look for their lips moving.

Our brains hook together the sound and the sight.

Then we understand.

Scientists are trying to understand how the frog does that, and that might help people who have a hard time hearing when they are in crowds. b

Check out the link on the back cover of this issue for more on Robofrog. Hurry, before I eat him!

17

Notebook

BY AMY HANSEN

Puzzles

18

s ' k i Rub ts e r c e S

BY PATRICA FOSTER

Check out the link on the back cover of this issue for more Rubik's Cube solving info!

Invented in 1974 by Erno Rubik, the Rubik’s Cube is fascinating and frustrating. There are dozens of techniques for solving it. The sides of the cube are called the Front (facing you), Back, Top, Bottom, Right, and Left.

Each side can be turned clockwise or counter-clockwise.

A center piece will always be a center piece. Likewise, edges are always edges and corners are always corners. The yellow center—and therefore the yellow side—will always be opposite white. Blue faces green, and orange is opposite red. Start by solving “the white cross”. Do this via “the daisy”: 1. Start with the yellow side facing up 2. Identity a white side piece 3. Rotate it until it’s next to the yellow center. Then, 1.

Look at one of the white middle pieces. What’s the color on its side? Rotate the top until that side piece matches the color of the center piece. (In the example: blue) 2. Flip the entire side 180 degrees. 3. Do this for the other three middle pieces.

Next, add the white corners. The most straightforward are the pieces on the bottom layer of the sides. 1. Rotate until the non-white side of the corner matches its center piece. (In the example: orange). This corner will replace the piece on top of it.

2. Move the corner “out of the way” by turning it to the side. (First image) 3. Bring the top row down. 4. Move the white corner back to its original position. It should now be beside the white center piece. 5.

Fix your white cross by twisting the row back up.

For the white pieces at the bottom, spin the bottom layer until the corner is directly under the piece it needs to replace. Now rotate the side so that the corner is on the bottom layer. Move it out of the way and fix your white cross.

If a white piece is in the top layer, bring it down to the bottom. Spin the bottom layer out of the way and fix your white cross. The white corner will either be on the bottom or one of the sides. Keep going until your top layer is solved! You’ll know it’s correct if each side has a colored ’T’.

The first layer can be solved with logic. The next two layers get trickier.

Most cubers memorize algorithms. For example, an algorithm to transform a yellow hook into a yellow cross looks like this: F, U, R, U’, R’, F’ which is a notation for Front (clockwise), Top (clockwise), Right (clockwise), Top (counter-clockwise), Right (counter-clockwise), and Front (counter-clockwise). Many cubers use mnemonic devices: tricks to help memory.

One device uses visual imagery. Instead of terms like Front, Top, and Right, one cuber decided to call his sides Face, Wings, Hat, Shoes, Knife, and Fork. Clockwise and counterclockwise became “old” and “new”. Turning the top clockwise was pictured as an old hat, and turning counter-clockwise was a new hat. The concept is to create pictures for move sequences.

Or, try stories. Josh Neufeld makes stories from move sequences. The pattern for fixing white corners starts with a scared kid at the top of the slide. Move out of the way so the scared kid can come down, then you climb up.

Then there's kinetic memory: the more you repeat an activity the more it becomes second nature. Some patterns pop up a lot in cubing algorithms. For example, R’FRF’ is called “the sledgehammer”, and FR’FR’ is “the hedgeslammer”. Instead of memorizing a list of moves, practice the sequence until it's automatic.

Cubing takes practice, but you'll solve it before you know it! b

Using letters, numbers, and special symbols like ^, $, and +, a regular expression (regex) is designed to match a specific pattern. The advantage of regexes is speed. They’re faster than regular code searches, and often portable from one language to the next.

Go to https://regexr.com/. Replace the sample text with this poem about sharks by John Ciardi: The thing about a shark is—teeth One row above, one row beneath.

Now take a close look. Do you find It has another row behind?

Still closer—here, I’ll hold your hat: Has it a third row behind that?

Now look in and… Look out! Oh my, I’ll never know now! Well, goodbye.

A few words in the poem will be highlighted. What do they have in common? Here are some rules for defining your patterns:

Challenge See if you can apply what you’ve learned to create expressions that match the following patterns: 1. Both ‘look’ and ‘Look’ 2. All 3-letter words that end with ‘w’ 3. All punctuation marks 4. All words that are 4 letters or longer 1. [Ll]ook 2. ..w 3. [^\s^\w] 4. \w*\w{4} With regexes, there’s always more than one correct answer.

Your solution may be different, but if it matches what it’s supposed to match, you’re golden!

Answers

1. Letters and Numbers (e, ea) A lowercase letter matches a lowercase letter. A capitalized letter matches a capitalized letter, and a number matches a number. Replace the expression on the webpage with ‘e’ or capital ‘I’. What happens if you type two letters together, like ‘ea’?

2. One Or the Other ([ea]) If you put those same two characters inside square brackets, the pattern with match either ‘e’ or ‘a’. This is useful when you need to match similar words, like cat, hat, and sat. In this case you could write the regex ‘[chs]at’.

3. Wildcard ( . , o.e) Type a ‘.’ and the entire text is highlighted, including letters, punctuation, and spaces. Dots are wildcards. If you’re not sure which character you need to match, but you want to match something, wildcards come in handy. Try the sequence ‘o.e’.

4. Escaped Characters (\s, \w, \W) Escaped characters combine a backslash and a letter. ‘\w’ matches any letter, while ‘\W’ matches anything but letters. ‘\s’ matches whitespace, including spaces, tabs, and new lines.

Escaped sequences are more specific than the basic wildcard, but they still offer plenty of flexibility.

5. Quantifiers (+, *, {2}) What if you want to match any four-letter word? ‘\w\w\w\w’ would work, but it’s a pain to write. Quantifiers are a convenient way to indicate how many times you want to repeat the previous character. ‘+’ means one or more. ‘ * ‘ is zero or more. Curly braces indicate a specific amount, such as ‘\w{4}’. Try comparing ‘te+’ with ‘te*’. (The star character can be unpredictable!)

6. NOT (^, [^a]) To avoid a certain character at all cost, use ‘^’ and square brackets. For example, to match anything except the letter ‘a’, type: ‘[^a]’.

Careful, though! ‘^’ has a different meaning outside the brackets. b

19

Coding

g x e n i g d e R Co

BY PATRICIA FOSTER

BY LES POUNDER

Electronics

20

You'll Need:

Intruder

• A microbit • Micro USB lead to connect micro:bit to computer • A 2xAAA battery holder and batteries to power micro:bit, or a USB battery • 4 x Crocodile Clips • A 3.5mm Powered Speaker • A laser pointer (or a flashlight) • A Light Dependant Resistor (LDR) Use the power of the micro:bit to keep your home safe (or your family out of your room!)

Unlike the Raspberry Pi, the micro:bit GPIO (General Purpose Input Output) pins feature analog inputs. This means that when a compatible component is connected, it returns a voltage, rather than a 0 or 1 (digital input/ output). This voltage is controlled by the sensor. For example, a potentiometer will have variable resistance depending on which way it is turned. In this project you'll use a Light Dependant Resistor (LDR) to monitor a light shone upon it. If the light beam is broken then our micro:bit alarm will alert us to an intruder. In this project you'll learn: • How to code with Python • How to connect components to

the micro:bit • How a Light Dependant Resistor works • How to generate sound • How a loop works • How a conditional statement works

This project consists of one circuit, controlled by the micro:bit.

(Check out the illustration, lower left of this page.) The first part of the circuit is our sensor, a Light Dependant Resistor (LDR). This is a resistor that changes its resistance based upon the amount of light it detects. For example, when the LDR has a flashlight shone upon it, the resistance increases, changing the voltage that is seen by the micro:bit.

If we cover up the sensor then the voltage increases.

Using one of the crocodile clips, connect one leg of the LDR to 3V, and then use another crocodile clip to connect the other leg to Pin 1 of the micro:bit.

The Circuit for This Project For more info on Micro:bit go to https://microbit.org/resellers

The second part of the circuit is a speaker which will play audio when triggered by the sensor. The speaker has a standard 3.5mm headphone jack, which has a tip and rings.

The top part of the jack is called the “tip.” Using a crocodile clip, connect this to Pin 0 of the micro:bit. Then connect the lowest “ring” of the jack, connect this to the micro:bit's GND.

The other part of the project is the laser pointer/flashlight, which will shine directly on the LDR. Note that even a laser pointer can cause eye damage and it should be used with great care. A flashlight will work well and will be much safer, especially for children.

Alert!

To code the micro:bit we used micro Python using the Mu editor.

You can download a copy of Mu for your operating system by following the instructions on their website: https://codewith.mu/.

In Mu start the code by importing two libraries of pre-written Python code. These are the micro:bit library, used to interface with the board, and the speech library, used to generate the synthesized speech.

Add this code:. from microbit import * import speech Next, create a loop that will continually run the code that you'll write inside of it. This kind of loop is an “infinite loop” and in Scratch it is called “forever”. In Python it is called “while True”. Any code inside the loop will run over and over again.

Use it to start the project. while True: Inside the loop, all of the code is automatically indented by four spaces or one press of the TAB key.

Never mix spaces and tabs together, otherwise Python will get angry and produce an error. Python uses indentation to identify code that is inside a loop, conditional statement, function, or class. The first line inside the loop creates a variable called “light” in which the value generated by reading the light level from the LDR will be stored. This will be a value between 0 and 1023. light = pin1.read_analog() Still inside the loop, now create a conditional statement: a test that will check the value stored in our “light” variable against a hardcoded value.

In this case we check to see if the

light level is below 1015. This value may require tweaking to suit the light levels in your home, so a little trial and error is encouraged. if light < 1015: Now, inside the conditional statement, specifically put the code which will be run if the light level falls below 1015. Print “ALERT” to the Python shell, to prove that an alert has been triggered. Then, instruct the micro:bit to generate simple synthesised speech, saying the phrase “INTRUDER ALERT”. Also, pass some parameters that control the speed at which the voice speaks: 120 is a medium pace, 0 is really fast and 255 very slow. You'll control the pitch: 100 being a mid range pitch, 0 high pitched, 255 low pitch.

Throat: 100 is mid range, 0 is nervous, 255 relaxed. Mouth: 200 means that our speech is well pronounced, 0 is tight lipped, 255 enunciates every letter.

After generating the speech, we instruct the code to sleep for 1000 milliseconds (1 second), so that our sensor isn’t repeatedly triggered too quickly. Add this code: print("ALERT") speech.say("INTRUDER ALERT", speed=120, pitch=100, throat=100, mouth=200) sleep(1000) You'll now break out of the if conditional test, and you must create a condition that will be tested when the LDR has not been triggered.

This is the resting state of our alarm system and for this you'll use an “else” condition. If the first condition, “if” proves to be False, then the "else" condition must be True. It simply

21

instructs the code to wait for 100 milliseconds (1/10th of a second) before the main loop repeats the entire process again and again. Add this code:. else: sleep(100) Here is all of the code for this project. Check that yours matches. from microbit import * import speech while True: light = pin1.read_analog() if light < 1015: print("ALERT") speech.say("INTRUDER ALERT", IMAGE FROM THE WEBSITE OF speed=120, pitch=100, throat=100, THE ÉCOLE POLYTECHNIQUE FÉDÉRALE DE LAUSANNE mouth=200) sleep(1000) else: sleep(100) In order to test the burglar alarm we need to write this code to our micro:bit. Plug the micro:bit into your computer using the micro USB to USB lead. The micro:bit will appear as a USB flash drive. In the Mu application click on “Flash” to write the code to the micro:bit. If you look at the micro:bit you will see a flashing yellow light on the back of the board, this tells us that the information is being written.

Once it stops flashing the micro:bit will reset and your burglar alarm code will run! Now, ensure that the laser/flashlight is shining upon the LDR sensor and then break the beam of light to trigger your very own alarm system!

For ideas on how to take this further, check out the link for this article on the back cover of this issue. b

Robotics

22

BY JENNIFER NEWELL

Sphero in Literature “It’s not possible that anyone could have that much bad luck.”

While reading The Grapes of Wrath in the comfort of their classroom in Long Island, a student opined out loud. His teacher, Mr. Richard Perry, realized he needed to change the curriculum to enable students to develop empathy for these characters from a very different place, the past. What he came up with sounds more like an idea from the future: robots.

How can a robot help students better understand the trials of the treacherous journey from Oklahoma across the Sierra Nevadas? Some of today’s robotic toys can be easily programmed to travel in given directions, make turns, and change speed. Mr. Perry does not claim to be an expert on robotics or programming, but he knew of the Sphero robot and was confident that it would be easy enough for the students to work with.

He received a grant that provided him with 10 Spheros.

He went to work creating a model of the Sierra Nevadas out of chicken wire, paper mache, and ground covering of various textures.

With the model of the mountains complete, students worked in groups to get Sphero from one side

of the range to the other. Although using a Sphero does not involve the suffering that the characters in The Grapes of Wrath endured, it did give students an idea of the challenges of navigating rough terrain.

Going too fast on the downward slopes leads to disaster. Not having enough speed approaching a steep section also leads to trouble. And the changes in terrain require many trials and errors. In the end, not everyone succeeds. But students realize that it's hard work to cross a mountain range, and it's common to have quite a bit of bad luck.

After seeing the student engagement during The Grapes of Wrath project, Mr. Perry came up with projects involving Sphero for units on Lord of the Flies and The Martian. In both cases, Sphero

increased student engagement and understanding of the literature. In Lord of the Flies each group’s Sphero is challenged in a way that reflects a character in the book. For The Martian project, students learned ASCII code to communicate with another school several states away!

Incorporating robotics into class has increased engagement with a broader range of students. Some students are more motivated by challenges connecting technology to literature than by traditional approaches to the subject. When I

spoke with Mr. Perry he mentioned an unexpected highlight of the Sphero project. A blind student in class was often a bit on the sidelines during group projects. However, while programming Sphero to cross a mountain range, this same student shone. His tactile approach to problem solving resulted in him making significant contributions to his group, which then went on to enjoy more success than the rest of

23

Class the class when crossing the terrain!

Both educators and students can imagine the potential for incorporating robotics into class projects. Studying history? Perhaps a Sphero could be used to explore westward expansion or the underground railway. Since Sphero works in water as well, it can cross model rivers, or perhaps even travel around South America or through the Isthmus of Panama.

None of these activities necessarily teach deep coding skills, but they do connect the basics of programming and robotics to all sorts of topics. And for teachers and students looking for deeper coding experiences, more coding challenges can be incorporated.

Most importantly, Mr. Perry discovered that basic robotics increases student engagement and gives them a fun way to connect with characters and stories across the curriculum. b

a, M , e e â&#x20AC;&#x153;G I wish a we had O!" R E H P S

POSTED ON FLICKR BY TULLIO SABA, PUBLIC DOMAIN

tidbitz

24

Turn Up the Heat

A deceptively simple jacket tracks your body heat and the outside temperature, and then it warms up or down as needed.

It’s a Kickstarter project from the Ministry of Supply, a company that mixes fashion with wearable tech.

It’s expensive, but it might give you ideas how clothing and tech might be useful. b

New App: Ink to Code

https://www.kickstarter.com/ projects/1850124313/ministry-ofsupply-the-first-intelligent-heated-ja http://www.wired.co.uk/article/ ministry-of-supply-kickstartermercury-jacket-self-heating https://ministryofsupply.com/ IMAGE: MONTY PYTHON AND THE HOLY GRAIL

Erase That!

Everything recorded by Amazon’s Echo, Google Assistant, and Apple’s HomePod is saved indefinitely for use by these companies.

Only Apple currently encrypts your voice recordings so they don’t know what you’re saying. While each company lets you delete your voice data, this article describes how to do it for each service. http://www.wired.co.uk/article/how-to-delete-amazon-echogoogle-home-data b

Microsoft has released a prototype Windows 10 app called Ink to Code to help software developers export sketches into a Visual Studio editor. The tool accelerates prototyping of Universal Windows Platform (UWP) and Android interfaces.

Developers sketch the underlying structure of code with a stylus on a touchscreen. The app turns the sketches into code. b

THEILR, FLICKR

https://www.microsoft.com/en-us/ garage/blog/2018/01/napkindisrupted-meet-ink-code-microsoftgarage-project/ https://www.microsoft.com/en-us/ garage/profiles/ink-to-code/ http://www.zdnet.com/article/ windows-10s-new-app-microsoftsink-to-code-turns-sketches-intoworking-code/

If You Want It Done Right, You Have to Do It Yourself

tidbitz

25

IMAGE FROM

When Maxime Coutté was 13, he WEBSITE LISTED BELOW wanted to try the Oculus Rift but could not afford the price. So he got together with friends and a math teacher to build a similar VR headset for $100. Then they opensourced the technology on Github so anyone can try and build one. b https://github.com/relativty/Relativ/blob/master/README.md

Ethically Speaking…

Universities that help produce some of Silicon Valley’s top talent want to bring a more medicine-like morality to computer science.

Harvard University and M.I.T. are jointly offering a new course on the ethics and regulation of artificial intelligence. The University of Texas at Austin offers a new course titled “Ethical Foundations of Computer Science.” Mehran Sahami, a CS professor at Stanford, is helping to develop a CS ethics course there. “Technology is not neutral,” said Professor Sahami. “The choices that get made in building technology then have social ramifications.” b https://www.nytimes.com/2018/02/12/business/computer-science-ethicscourses.html

One Man's Toy Is Another Man's Treasure Design duo Thomas and Allie of Hint Lab have designed a line of playful, elegant jewelry that uses LEGO®compatible Shapeways 3D printed settings to transform the colorful building blocks from toys into gemstones. Look for Hint Lab's work on their Etsy shop and follow their work on Instagram.

Please note that Shapeways and Hint Lab are not affiliated with the LEGO® Group and brand. b IMAGE FROM SHAPEWAYS.COM

Using LiDAR on a Dig When researchers surveyed the ruins of a Purépecha Empire city in Mexico, they used LiDAR, which gave them the power to see underneath the lava that covers Angamuco.

Thanks to the laser technology, they now know that the city occupied 26 square kilometers.

"That is a huge area with a lot of people and a lot of architectural foundations," Chris Fisher of Colorado State University told The Guardian.

LiDAR also led to the discovery that the city had big structures like pyramids and open plazas.

The Purépecha people existed at the same time as the Aztecs.

Based on the team's LiDAR scans, Fisher said Angamuco, as far as we know today, was the biggest city in western Mexico during that period. b —Adapted from a story in the Guardian featured on engadget.com, as reported

by Mariella Moon on 2/7/18

TECH I.R.L.

26

HOP TO IT

IAN SANE, FLICKR

Tech in

In my city of Portland, Oregon, our TriMet transit system just rolled out a new way to pay for transit fare: the Hop Fastpass system.

Hop simply involves a card the size of a credit card that you tap onto a pedestal at a train station or inside a bus and your fare is paid.

No more cash to keep track of or cell phone apps to keep charged.

It feels magical when you first use it. You tap it every time you get on transit but you're only charged when you don't have an already active ticket. If you've used two tickets that day, then you're upgraded to a day pass and won't be charged again until after 2am that night. If you've used 20 days worth of tickets (the same cost as a monthly pass), then you're not charged for the rest of the month.

There's logic, decision making, identification, and network communication happening every time you tap the card.

The card is a Radio-Frequency IDentification (RFID) card. You may have seen RFID technology used in things like identifying library books during check-out. The HOP card is passive, only broadcasting its unique identifier when triggered by the presence of a receiver. The pedestals are running a version of Linux. The code it's running to read the card and communicate with its servers is written in C and C++.

The code for the TriMet servers is C#, handling the actual lookup of

account information to see whether you have an active ticket.

A lot of the odds-and-ends code to integrate pieces of the system and do things like checking system logs is written in Python.

Getting all of this software and hardware reliably working was a big job. Over a dozen different companies, including Google, were involved in the development and implementation of this transit system. They needed to handle the fares collection and securely allow you to connect credit or debit cards to your account. They also implemented the systems to allow you to refill your card at stores.

TriMet also worked with other local tech companies like New Relic to monitor the health of the system.

There's often a lot of work that goes into seemingly small things.

But there's a lot of opportunity in civic-minded technology. If this much works goes into paying for transit securely and reliably, imagine what might go into a system to help people be matched with affordable housing, or allowing secure online voting. There are many ways technology can make life better. b

BY CLARISSA LITTLER

CORY SCHADT ON UNSPLASH

27

Real Life PARK IT HERE

Human drivers are getting more support from technologies that are gradually leading us to autonomous vehicles. Improved sensor technology is available at increasingly lower costs.

Adaptive Cruise Control

With adaptive cruise control the driver programs the distance she wants to maintain between her car and the car ahead, not the speed to maintain like traditional cruise control. The car will speed up or slow down in order to maintain this distance until the driver pushes the gas or brake. This uses radar, which works by emitting radio waves and measuring how much time passes before they are reflected back. A computer in the car can continually calculate the distance between a car and an object. When the distance becomes less than the minimum set, an alert will sound.

Lane Departure Alert with Steering Assist (Lane Keeping Assist)

Many new cars have a small camera tracking the road ahead.

Software converts the visual data from the camera into patterns that the car’s computer system can recognize. If the lanes are clearly marked, the camera will “see” if the car begins to drift from one lane to the other. In some systems, the car is programmed to remain centered in its lane and auto steering is activated.

Parking Assist

Parallel parking can be challenging. A driver must estimate whether or not her car will fit in a given spot, and adjust the angle of entry to avoid bumping the surrounding cars and the curb.

Fortunately, sensors can help. The two most common sensors found in parking systems are ultrasonic and electromagnetic. Ultrasonic sensors send out sound waves and detect the distance between the parking car and surrounding objects by measuring the time it takes for the waves’ echos to return.

Electromagnetic sensors create an electromagnetic field around the car bumper. When an obstacle enters that field, it sends a voltage spike through the sensor. The size and distance of the obstacle can be determined by the car’s computer.

In the most advanced systems, the car can steer itself into a spot.

The ultrasonic sensor tells the driver whether or not to accept a given parking spot. Then the steering system takes over and parks the car, while the car tells the driver when to accelerate, brake, and shift from reverse to drive. The driver can interrupt the process by gripping the steering wheel.

Many of us will soon find ourselves riding in semiautonomous vehicles while society prepares for fully self-driving cars. b

JOSH BANCROFT, FLICKR

ANDREW R., FLICKR

BY JENNIFER NEWELL JASON THEIN, FLICKR

Notebook

28

s M n E o T i t S p t O a e p r m a 6G C r e m Sum

BY ERIN WINICK

Girls Who Code

This expanding program is a fantastic opportunity for girls to try out coding or expand their knowledge. There are different program options including a coding immersion course and after-school clubs around the country. Many of the programs have scholarships available and are free to attend. https://girlswhocode.com/ Engineering for Kids

Local versions of this national organization offer many programs focused on a variety of science and engineering concepts. Get hands on and build! http:// engineeringforkids.com/ JoAnn Fabrics Sewing Camps

Sewing gives you a great opportunity to try out operating a machine and learn to make fun 3D creations out of 2D fabric. JoAnn Fabrics camps offer classes for various skill levels and ages. Some are project-based and will teach

you how to make a shirt or a pillow.

Have some hands-on STEM-related fun! http://www.joann.com/ classes/in-store-classes/kids-andteen-classes/ SWENext Clubs

Hosted by the Society of Women Engineers, SWENext is a chance for girls ages 13 and up to meet up with older kids interested in engineering, do fun hands-on activities inspired by engineering, and meet women engineer role models. There are many different local clubs to join.

Many host fun one-day events for you to try out the club before becoming a member. http:// societyofwomenengineers.swe. org/swenext-clubs NASA Camps

Space Camp is the PERFECT summer camp for space-loving kids ages seven and up. They have different programs depending on age. It's run by NASA and is offered in Huntsville, Alabama.

Pilot a space shuttle simulation,

get suited up in astronaut gear, and train like astronauts! https://www. spacecamp.com/. You can intern or work at NASA as early as age 16!

They want to give you opportunities to explore space even earlier.

Local science museum camps

When I was a kid I attended science camps at the local Museum of Science and Industry. There are many programs at museums near you to explore. Check out the websites of local science museums, zoos, and natural history museums and see what camps or events they offer. https://www.mosi.org/ camps/ Do you have an interest in a specific area of science not listed here? Donâ&#x20AC;&#x2122;t fret! Many scientists and engineers will want to help you out. Try reaching out to people at local companies or colleges that are studying or working on projects you are interested in. You never know, you might have the chance to follow one of them around for a day or tour their lab. Donâ&#x20AC;&#x2122;t be afraid to get out there and explore science! b

US ARMY CERDEC MATH & SCIENCE SUMMER CAMP, FLICKR

Despite primarily teaching programming and robotics, I begin each year with an engineering challenge. I ask students to build a freestanding office supply tower out of paper, index cards, wire hangers, and tape. I give students only two rules: you have to make use of all the materials provided to you, and you can have as much masking tape as you need. At this point the 3-person groups jump into action, although I know that many will not yet understand the double-edged sword that is masking tape. While I observe, I learn an incredible amount about the soft skills students bring to the classroom.

Some students barrel through a first failed attempt with grit. Others have difficulty working in teams and invest too much time in faulty designs. By the end they all come to realize that, despite its abundance, masking tape is heavy. As their towers list to the side burdened with tape, they have a better understanding that gravity is a force to be respected.

I have come to see these lessons as more than an enjoyable on-ramp to the year. Lessons that incorporate kinesthetic learning are an essential ingredient in the STEM classroom because they reach students that traditional coding courses can repel.

Kinesthetic learners learn while doing. They can be turned off by long sessions at a computer screen.

It is harder for them to codify and retain information when it is presented visually or spoken orally.

Due to these barriers, they can begin to believe that technology is “not their thing” or they aren’t

“computer smart”. The constructivist educator Samuel Pappert, I assert, would have disagreed with them.

An MIT professor and cofounder of the MIT Media Lab, Pappert believed that students learn best when they are actively building things. He created the LOGO language and the first iteration of turtle programming—a roving, drawing turtle robot. As a Computer Science teacher, I find I am continually returning to Pappert’s teaching philosophy.

Pappert’s encouragement of making and doing as a part of computing is an idea that has inspired much of the maker movement, and continues to influence educators today. I keep a copy of his article “Twenty Things to do with a Computer” in my room at all times and return to it frequently.

In a recent lesson on algorithms and route finding, I taped small Xs one meter apart on the carpets around the intersecting hallways of our school. Routefinding algorithms can be quite complicated to implement, but are simple in theory. Students were given starting points and destinations and had to find the optimal route by numbering the steps working backwards from their destination.

I watched as students made assumptions about the fastest route. I saw greater numbers of engaged students. They digested a complicated topic quickly.

Moreover, the lesson became an instructive model for algorithms and how they work.

Some days my classes look more like drama warm-ups as students are in my room acting out how logic gates work. Or it can

look like a gym as they observe a jumping student to better program gravity into game design. As much as possible, I try to pair kinesthetic activity with coding concepts.

The convenience of the internet and modern computing has reduced the physicality of programming—to the detriment of some students. Getting students walking in the footsteps of innovators like Samuel Pappert and Admiral Grace Hopper helps keep STEM inclusive. As a teacher who is trying to capture all the diverse learners out there, I find it is essential to what I do. b

PHOTOS: TOP, FABRICE FLORIN, MAKERSPACE, FLICKR; CENTER, US NAVAL FORCES CENTRAL COMMAND, FLICKR; BOTTOM, AMERICAN FARM BUREAU FEDERATION, YF&R CLASSROOM VIST, MICHAEL LOBIONDO, FLICKR

Tim McGuigan teaches middle school Computer Science and Robotics and is the Farrell Chair for Innovation at Shady Side Academy.

29

Parent and Teachers

c i t e e h c t n s e e i Kin uter Sc p m o C

BY TIM MCGUIGAN

“Computing is not about computers any more.

It is about living.” —Nicholas Negroponte Thank you for reading this issue of beanz ! Check out the links below to read stories from this issue online with links to learn more.

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Friend http://beanzmag.com/ diy-digital-assistant Puzzle Me This! http://beanzmag.com/ sketchup-jigsaw-puzzle It's All in How You Look at It http://beanzmag.com/ google-expeditions Save the Drama for the Llama http://beanzmag.com/ llama-emoji Unbreakable! http://beanzmag.com/ navajo-code-talkers Let'ssssss Write a Game http://beanzmag.com/ pygame-basics

Boids: AI in Flight http://beanzmag.com/ scratch-boids-ai

Sphero in Literature Class http://beanzmag.com/spheroenglish-class

Modding Out http://beanzmag.com/ minecraft-modding

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Seeking Clojure http://beanzmag.com/clojure

TECH I.R.L. http://beanzmag.com/ tech-irl-self-driving http://beanzmag.com/ tech-irl-hop

Robofrog Goes a'Courtin' http://beanzmag.com/robofrog Rubik's Secrets http://beanzmag.com/ solve-rubiks-cube Coding Regex http://beanzmag.com/ regex-challenge Intruder Alert! http://beanzmag.com/laserburgler-alarm

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