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Stewart's Blog

Stewart Watkiss website to the world ...

(Children, computing, first aid and other ramblings ...)

TinkerCAD 3D Snowman for 3D printing G-Scale model railway

December 3rd, 2018

This is a model that I’ve made using TinkerCAD. A snowman designed for 3D printing on a home 3D printer. It’s been created to approximate G-Scale (1:22.5) for outdoor model railways. It’s also hollow so that you can insert an LED inside and have it light-up (assuming it’s printed with a light coloured PLA) so it can be used as a light-up Christmas decoration.

G-Scale Snowman made in TinkerCAD for 3D printing

The photo below show the 3D snowman printed on a Wanahao i3 Duplicator Plus using white PLA.

To make it easier to hollow out there is a central cylinder which can be removed. The snowman arms are very delicate at this scale. If the size isn’t important then you may prefer to scale the model up a little which can be done within your Slicer software (eg. Ultimaker Cura).

GScale Snowman made 3D printed for garden model railway

Download 3D model files (STL)

Video – Beginners Guide to TinkerCAD

Below is a video on how to recreate the snowman in TinkerCAD

More models

See the PenguinTutor 3D projects page for more 3D models, including more model railway models.

The rules for building a model railway

November 25th, 2018

There are many different misconceptions about creating model railways and the people that are involved. I’d therefore like to start by dispelling some of these myths and explaining what I think that model railways is about.

The 3 Golden Rules of Model Railways

Many people have come up with different rules for model railways, here’s my take.
If you are wanting to design your own personal model railway then there are only three rules that you need to follow.

  1. Safety is always the top priority
  2. It’s your railway so you can do what you want
  3. See rule number 2

Okay, so that’s only really 2 rules, but both are just as important. You also need a reason to be spending all that money, so I included fun as a third rule in the description below.
This is for your own railway on private land, but if you are on a public display then new rules apply – see Public Display Railways rules.

Rule 1 – Safety

I think it’s fairly obvious why rule number 1 exists, but remember this applies to both the modeling and the display of the model railway.

Who is going to view the railway and in what environment?
Have you checked there are no exposed live electrical components that could be a danger. For example check the plug is wired correctly and that there is no damage to the mains electrical cable. If it’s an outdoor model railway then are all mains electrical parts suitably waterproof or located indoors?
If young children are going to be present then make sure they are no at risk of choking on small objects. In many cases this is best achieved through close supervision whilst they are viewing / interacting with the railway, but you may also want to consider adding a transparent plastic (perspex) screen to prevent them reaching the railway or designing a layout that is child friendly.

Health and safety for model railways - PPE goggles and ear protectors

When modeling – do you know how to use the tools, are you following the manufacturer instructions and are you wearing appropriate PPE?
When dealing with small models then it’s easy to make the mistake of thinking that the risks are also much smaller, but that is not the case. When using something like a rotary multi-tool / drill then the tools can be be spinning at thousands of revolutions per minute. If a small piece of metal or plastic is thrown out at that speed and hits your eye then it can result in permanent loss of sight. In fact due to the thickness of the cutting blades there is an increased risk of a blade breaking off and hitting you. I know that from experience (fortunately I was wearing eye protection at the time, but it could have been different).

Rule 2 – It’s your railway

If it’s your railway then you can do what you want, which is to say that you make up your own rules of how you want the model railway to look. This is based on you wanting to create a railway for yourself. If you are wanting to participate in a club model or create a model for public exhibition then there may be other rules you need to apply, but when modeling for your own pleasure then you make up your own rules.

Rule 3 – It should be fun

Why are you creating a model railway. For most of us it’s because it’s something you enjoy (or you want to try it and see if you enjoy it). Which comes back to rule number 2, you decide what the rules are that will make it enjoyable for you. If you can’t afford to buy expensive scale models and want to include some cheap toys in your layout (Playmobil works very well with Garden Gauge Railways), or if you really want to incorporate something but it’s not quite the same scale or a different era then do it. Feel free to do what you want and as long is it makes you happy then it’s the right thing for you.

What kind of person likes model railways?

You may be under the impression that model railways are just for boys and men that still think they are kids, but that is not the case at all.

Model railways are good for all ages, from young children to great-grandparents,and ability. It’s also just as much fun for girls, whether the girl is into science and engineering and likes those aspects of building a model railway, whether they are a historian and want to make it historically accurate or they prefer to make some kind of fantasy / science fiction world. There is not reason that model railway should be any less appealing to girls as it is to boys. There is something for everyone.

Sci-Fi layout from British Model Railway Challenge
Sci-fi layout winner of the British Model Railway Challenge TV program.

The skills involved in creating a model railway depend upon the type of layout. They could vary from digging the garden and building a brick wall to support an outdoor railway, to painting N Scale model people that are only 1cm tall. There is lots of scope for STEM subjects such as electronics and mechanical engineering; all manner of art from creating scenery items or painting realistic backdrops; and a role for the historian to check on historical accuracy (if that’s the type of layout you want).

Most model railway layouts attempt to create an element of realism, but if that’s not your thing you could create a fantasy land with unicorns, sci-fi space planet or a scene from a horror movie, whatever direction your imagination takes you.

How much space do you need?

You may be thinking that you don’t have the space for a model railway, but having seen some space constrained layouts I’m pretty sure that’s not the case. Many OO scale layouts can fit comfortably under a single bed, N gauge is smaller still and I’ve seen an impressive 9mm narrow gauge layout which packed away inside a box smaller than a briefcase. T-scale is smaller still, although the tiny size of those models is a little too small for me (although amazing to see some of the models that some people have made). Just take a look at the photo below of one that I saw at the Warley Model Railway show 2018.

Small model railway - From Warley Model Railway Show 2018

If you haven’t got space in the house, then how about the garden (if you have one)? It’s a great way to involve the whole family by choosing plants to grow next to the railway.

Guidelines / Information / Hints and Tips

As I said the only really rules for your own railway are the ones you impose on yourself. I have put together a few guidelines that you may want to consider. Feel free to go against these guidelines if you have a reason for doing so.

Scale, ratio and gauge

These are three terms that are often used interchangeably, although there are some subtle differences. Scale refers to something having a direct correlation with real size (usually smaller). The difference in size of a scale model is normally expressed as a ratio, often following one of the common named ratios. The gauge is the distance between the track, but often scale and gauge are used interchangeably as the distance between the gauge is normally based on the same ratio as the scale for the models (though not always quite the same).

The standard gauge for British (and most other country) full size track is 4ft 8½in. Model railways are often based on a scaled down version of standard gauge. Some railways are closer together than standard gauge which is often known as narrow gauge or light-railways. These narrow gauge railways are popular for some railway modellers as they make good model layouts with only a few carriages. The ones marked in the table with an * are narrow gauge railways.

The table below shows some of the most common scales used for British and European model railways.

Name Ratio Gauge Comments
T scale 1:480 3mm This scale is unbelievably tiny. It does look good, but I expect is very difficult to model in.
N scale 1:148 9mm This is a common model railway for those looking for a smaller scale for 9mm. It can be particularly useful where you want to model a large layout, but don’t have the space to create it in one of the larger scales.
OO scale (Double Oh) 1:76.2 16.5mm The most common scale of model railway used within the UK. Ideal for use in a loft, garage or under the bed. The track size is the same as HO, but the scale used for models is slightly bigger making it a little out of the proper ration.
HO (Half-O) 1:87 16.5mm The most common size of model railway used in continental Europe. Similar to the OO standard and on the same width, but with a more realistic ratio.
O Scale 1:45 32mm A scale often used for larger scale models and for some outdoor railways.
16mm Scale 1:19.05 Usualy 32mm * Use for some narrow gauge outdoor model railways in the UK (less popular in Europe).
G Scale 1:22.5 45mm * Also known as garden gauge this is a popular scale for modeling narrow gauge railways that can be used outdoors. There is a wide variety of pre-built items available, although often these are based on European or Americal railways.
Gauge 1 1:32 45mm Less common than G Scale these are standard gauge trains running on the same 45mm gauge as G scale.
Gauge 3 1:22.5 64mm The same scale as G scale, but with wider gauge track for standard gauge trains. Needs a lot of space compared with the other scales listed.

* These are the gauges used for narrow gauge tracks.

Some model railway enthusiasts are very strict in ensuring that where possible their model is true to their desired scale. It is however fairly common for some to use a similar scale when off-the-shelf models are not quite to the same scale. The use of HO and OO on some models where some scenic items intended for European countries are mixed with UK OO scale and a similar thing can happen with 16mm and G-Scale (although the track gauge is different the model scale is quite close).

Belos is an example of a narrow gauge – G-Scale railway.

Example of narrow gauge - G-Scale railway

Era or Theme and Historical Accuracy

Deciding upon a theme or year for the model railway to be based should be an early consideration. You should also decide on how important historical accuracy is to you.

This is perhaps one of the most controversial areas: the model railway purists may insist that you shouldn’t include anything that doesn’t comply with the historical accuracy at the time however having made an investment in a particular item then you may be keen to include that regardless of it’s historical accuracy.

There are sometimes stories that you can use to incorporate the items from a different era. For example if you have a modern railway layout, but would like to include a steam locomotive then you could design in a preservation railway within the layout, or just give a story that it is a historical railway running on the mainline.

At the end of the day remember the three rules above. If you want to include it, but it doesn’t fit with the accuracy then it’s your railway and if you are enjoying creating it then it doesn’t matter if it isn’t historically accurate.

Weathering or New

When buying a model then the chances are that it looks like a pristine brand new version. Weathering is the process of making a model look more realistic by making it look older and dirty. Not everything needs to be weathered as it’s always possible that, if age appropriate, it really is a new locomotive just delivered from the factory. It’s unlikely that all engines and buildings would look brand new.

On the other-hand some people may not want to spray dirty black / brown paint over their brand new model. If that’s you then don’t worry, just leave it as it is and accept how it looks.

Public Displays

When it comes to public displays then there are additional rules that you should follow. These apply whether the display is part of an exhibition, an outdoor public layout such as one at a preservation railway station or an open display on your own land. The main thing is an additional responsibility for health and safety and public liability insurance.

In addition the health and safety considerations already mentioned you may need to look at hazards around the site and periodic testing and certification of live steam engines. For electrical layouts you may need to consider PAT testing of electrical equipment that is in reach of visitors (or better still keep mains electricity away from the visitors).

Liability insurance is a requirement for public displays. If you are part of a model railway society check with them as they sometimes provide public liability if you have an “open day” at your own railway at your home. If not then make sure you take out insurance for a public event.

Thought should also be made about how accessible it is to disabled visitors as there may be a need to make reasonable adjustments for disabled access under the E qualities Act, particularly for a static display.

One final thing that I feel strongly about is swearing. If you are on a public display there should be no need to use bad language particularly when young children may be listening. This happened to me recently as we visited an outdoor model railway at a preservation railway station. One of the members there was talking with other members and used a completely inappropriate 4-letter word which was clearly audible to my son. Once may be a slip-up but then he repeated the same word again straight afterwards. It’s a word that I certainly wouldn’t ever use whilst with my children and was completely inappropriate.

Summary

There are very few rules beyond the need to keep yourself and others safe.

In my opinion having fun is much more important than realism or historical accuracy, but that is something you may want to think about when creating a layout for public display.

Model Railway – designing a G-Scale building for an outdoor model railway in the garden – part 1

November 24th, 2018

This is my first attempt at creating a proper scale model for 3D printing. In this case I am creating a weigh building in G-Scale. This has been a huge learning curve. I’ve since learned from some of the issues in the first model and so part 2 will improve on the techniques shown.

The model is based on a real building located at Winchcombe Station on the Gloucestershire and Warwickshire Steam Railway. The building is opposite the entrance to the station. See the photo below:

Weigh bridge building at Winchcombe Station on the Gloucestershire and Warwickshire Steam Railway

The 3D printed version is approximately in G-Scale (1:22.5 scale). This is also known as garden gauge railway, designed for narrow gauge trains running on 45mm track. It may also work well with 16mm model railways as the size is perhaps a little smaller than G-scale. The main difference between the real building and the scale model is that the model does not use the different coloured brick that is in a curved shape above the window and where the side walls meet the roof. The main reason for this is the time it would take for a feature that I expect few would actually notice if I hadn’t pointed it out.

3D printed model railway Weigh bridge building in G-Scale

Designing the model

The model was designed in TinkerCAD. In this version I have created the model in several parts.

  • The main part of the building from the floor to the top of the door
  • Upper part of the building (including the side walls up to the pitched roof)
  • Internal fireplace and chimney breast
  • Roof
  • Windows (not shown in the photo above)

In general this works, but in a later version I will combine the first three into a single model. The reason for this is that there was some warping of the upper part of the building (perhaps due to the bed temperature). Although this is something that I will need to revisit again in future when creating larger buildings.

The internal fireplace is something that I added as an afterthought on this model, but will be included directly in the next version.

I have created a short video on getting started with TinkerCAD which explains about how to create a simple brick wall.

3D Printer

The printer that I have is a Wanhao i3 Plus Duplicator. This is the perfect size for creating this 3D model, which fits fairly comfortably on the build plate. It would not be possible to create a larger building in a single print using this printer. If a larger building is required (as I hope to do in future) then the model will need to be separated in parts and then fastened together.

Brick effect PLA filament for 3D printer

One of the challenges was in finding an appropriate colour PLA to give a good brick effect. The problem with most suppliers is that the closest the provide is either red which tends to be a bright post box red colour, or brown which is too dark. I had tried experimenting with different colours with acrylic paint when creating a brick wall previously, but then I came across a brick effect PLA filament from Filo Alfa. I couldn’t find a UK supplier for the FiloAlfa PLA so I ordered it direct from the manufacturer in Italy. Unfortunately whilst the cost of the PLA is quite reasonable, the additional cost of shipping meant it was in fact very expensive. I am however very happy with the quality of the PLA which works very well in my Wanhao 3D printer.

Brick Effect PLA 3D printer element from FiloAlpha

The rest of the building (roof and window frames) is made using my normal 3D printer filament for which I normally use either Prima Value PLA (1kg reels) or Prima Select PLA (750g reels) depending upon the colour availability.

Download the files

You can download the current version using the link below. I do however suggest you wait until the new version is available which will provide an improved design.

Creative Commons Licence
G-Scale Weigh Building by Stewart Watkiss is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
This applies to the Weigh Bridge STL files only. Other files on this website may have different license terms.

JLL Piano – Raspberry Pi Music Clip player

October 15th, 2018

This project is called the JLL piano. This is a school project that my daughter created for her music homework. She needed to create a project that related to Jerry Lee Lewis and she created a mini piano that plays a short clip for a different song depending upon the key that is pressed.

Raspberry Pi Piano Hat

It uses a Raspberry Pi with a Pimoroni Piano Hat.

You first need to setup the Piano Hat using the Pimoroni Piano Hat install instructions. Then create the following in a text editor.
The program will work in Python 2 or Python 3.

You can of course change the music clips to be any music you prefer.

import pianohat
import time
from pygame import mixer

# Change key numbering (black keys = -1)
keys = [0,-1,1,-1,2,3,-1,4,-1,5,-1,6,7]

sound_files = [
"/home/pi/MusicClips/jll-wholelotofshaking.wav",
"/home/pi/MusicClips/jll-greatballsoffire.wav",
"/home/pi/MusicClips/jll-milkshake.wav",
"/home/pi/MusicClips/jll-mynameisjll.wav",
"/home/pi/MusicClips/jll-itllbeme.wav",
"/home/pi/MusicClips/jll-highschoolrocking.wav",
"/home/pi/MusicClips/jll-waitinforatrain.wav",
"/home/pi/MusicClips/jll-whenimshaking.wav"
]

def inc_volume(ch,evt):
if evt:
change_volume(1)

def dec_volume(ch,evt):
if evt:
change_volume(-1)

# Change volume by amount specified 0 to 10 (+1, -1 etc.)
def change_volume (change):
#print ("Change volume "+str(change))
if change == 0 : return
# volume is 0 to 1 so divide by 10
delta = change / 10
new_volume = sounds[0].get_volume() + delta
if new_volume > 1:
new_volume = 1
if new_volume < 0: new_volume = 0 for this_sound in sounds: this_sound.set_volume(new_volume) def handle_note(channel, pressed): if pressed: channel = keys[channel] if (channel < 0): return mixer.stop() sounds[channel].play(loops=0) mixer.init(22050, -16, 2, 512) mixer.set_num_channels(13) sounds = [mixer.Sound(sound_file) for sound_file in sound_files] pianohat.on_note(handle_note) pianohat.on_octave_up(inc_volume) pianohat.on_octave_down(dec_volume) while True: time.sleep(0.001)

Programming games with Pygame Zero

October 15th, 2018

Recently I’ve been programming some games using Pygame Zero. Pygame Zero is combination of libraries and other code that interfaces with Pygame to make it easier to program graphical games (or other applications). I’ve created two games so far one of which is designed for the Picade, Raspberry Pi based mini Arcade Machine and the other second is mouse based.

Compass Game

This is the compass game. Use the joystick (or cursor keys) to move the character around the field.

Compass game for Raspberry Pi Picade

More details see:

Memory Card Game

This is the a memory card game. It’s mouse driven.
The supplied cards are based on photos from the Lake District in the UK.

Memory Card Game for Raspberry Pi

More details see:

Updated Linux and Raspberry Pi Tutorials

March 27th, 2018

One of the things about creating a web site is having to keep it up-to-date as changes happen. In the case of my PenguinTutor web site that is the changes in Linux and the Raspberry Pi over the last few years. In particular a new release of Raspbian was created last year (based on Debian Stretch) and the latest Raspberry Pi (Raspberry Pi 3B+) was released recently. I’ve now updated the Linux Tutorials and Raspberry Pi guides to reflect those changes. I’ve also taken the opportunity to add some new material including an overview of computer networking and a basic introduction to running Samba on the Raspberry Pi.

I’ve also added a photo of the latest version of the Raspberry Pi.
Raspberry Pi Model 3B+

I still need to review the LPI practice exams (I do try and review them fairly frequently, but it is due another revision) and as a historical record the blog pages won’t necessarily get updated (although I do sometimes add updates where necessary). But for now most of the pages should be up-to-date.

Raspberry Pi 6th Birthday – Birmingham Raspberry Jam 2018

March 3rd, 2018

Today is the weekend of the Raspberry Pi 6th Birthday. In the past the birthday has been celebrated with a large Raspberry Jam in Cambridge (organized by Mike Horne and Tim Richardson). I have been to the earlier birthday celebrations, supporting workshops run by others, giving presentations and running workshops.

For 2018 the birthday celebrations have been expanded to enable more people to take part with over 100 Raspberry Jams around the world. The nearest to me is the West Midlands Raspberry Jam at Birmingham which is organized by Tim Wilson and Spencer Organ. I volunteered to give a short talk and run two workshops at the event.

Unfortunately due to a large amount of snow and safety concerns the event has had to be postponed. The event will hopefully be rescheduled in a few weeks time.

In the meantime I thought I would still make my presentation and worksheets available as planned during the weekend. I still plan to give run these when the Birmingham Raspberry Jam can be rescheduled, but they may be useful in the meantime.

Creating Games on the Raspberry Pi – Space Asteroids

The talk and workshops are all on creating a game for the Raspberry Pi, from creating your own sprites to coding in Scratch or Python Pygame Zero and adding a controller using simple electronics.

The game is a cross between Space Invaders and Asteroids. All the sprites are created from scratch and programmed to interact with electronic button switches and an LED.

Talk on creating sprites using Blender

This is a short talk about what Blender is and how it can be used as a tool when looking to create computer games.

Raspberry Pi Birthday 2018 - Blender talk
Raspberry Pi Birthday 2018 – Presentation notes for talk on using Blender to create Sprites for computer games.

Workshop – Create Space Asteroids, physical computing computer game for Raspberry Pi – Scratch Version

This worksheet is created for a version of the Space Asteroids game that is created in Scratch 2 on the Raspberry Pi.

It’s designed for those young and old who have preferably done a bit of Scratch programming before, but want to take first steps in physical computing or designing an interactive game. It’s also suitable for complete beginners to Scratch, who may need some help to get started with using Scratch.


Space Asteroids physical computing game for the Raspberry Pi - Scratch version  2
Worksheet – Space Asteroids physical computing game for the Raspberry Pi – Scratch version 2

Workshop – Create Space Asteroids, physical computing computer game for Raspberry Pi – Python Pygame Zero version

This worksheet is created for a version of the Space Asteroids game that is created in Pygame Zero (Python 3) on the Raspberry Pi.

This is designed for older students and adults that have already done some programming in Python, but want to learn about designing games in pygame zero or how to connect to simple electronics using gpio zero.


Space Asteroids physical computing game for the Raspberry Pi - Pygame Zero and GPIO Zero (Python 3)
Worksheet – Space Asteroids physical computing game for the Raspberry Pi – Pygame Zero and GPIO Zero (Python 3)

World Book Day – Raspberry Pi and Pimoroni InkyPHat Badge

March 1st, 2018

Today is World Book Day. For the last few years I’ve been supporting my local school by helping run their book sale. Last year I dressed up as The Wizard of Oz complete with Wearable Electronic flashing bow tie. This year I am a little more subtle as I won’t be wearing a full costume, but still keeping with the wearable electronics I’ve gone for a Raspberry Pi powered electronic badge.

InkyPHat wearable Raspberry Pi badge for World Book Day

The badge is based around a Raspberry Pi Zero W, mounted in a Pimoroni PiBow case and a InkyPHat display. The display is based around ePaper / eInk technology (similar to how the original Kindle works). This means it uses very little power and will continue to display the output even after the power is switched off. It does have a bit of a flicker when it refreshes the screen (which takes a few cycles to update), but that only draws attention to the badge. Unlike most other ePaper displays this one can display more than one colour. It can display images in Red, Black and White (although one of these is likely to be the background colour).

You can see the badge in action on the short video below:

I’ve also included the source code of the program, for this you will also need a png file which needs to be created using a 3 colour palette (more details of how to create an Inky Phat compatible image are provided here).

Source code for Raspberry Pi InkyPHat World Book Day badge

#!/usr/bin/env python

import inkyphat
import time
from PIL import ImageFont, Image

font = ImageFont.truetype(inkyphat.fonts.FredokaOne, 32)

message = ""
w, h = font.getsize(message)
x = (inkyphat.WIDTH / 2) - (w / 2)
y = (inkyphat.HEIGHT / 2) - (h / 2)

font2 = ImageFont.truetype(inkyphat.fonts.FredokaOne, 28)
message2 = "Books are\nFun!"

w2,h2 = font.getsize(message)
x2 = (inkyphat.WIDTH / 2) - (w2 / 2)
y2 = (inkyphat.HEIGHT / 2) - (h2)

while 1:
inkyphat.clear()
inkyphat.text((x, y), message, inkyphat.RED, font)
inkyphat.show()
time.sleep(10)

inkyphat.clear()
inkyphat.set_image(Image.open("/home/pi/wbookday01.png"))
inkyphat.show()
time.sleep(10)

inkyphat.clear()
inkyphat.text((x2, y2), message2, inkyphat.BLACK, font)
inkyphat.show()
time.sleep(10)

The image file is below:

World book day InkyPHat image

ESA European Astro Pi Project – Mission Zero – Code that ran on the International Space Station

February 15th, 2018

The ESA European Astro Pi Project – “Mission Zero”, involved school children creating code that actually ran on the International Space Station (ISS).

My son joined with a friend (both aged 9 at the time it was submitted) to create a Python program that ran on the International Space station during February 2018.

Here’s his story:

The AstroPi shown in the video is a 3D printed replica of the Raspberry Pi case that is installed on the Space Station. It includes the Raspberry Pi Sense hat which shows the LED display and includes the temperature sensor.

The project gives a friendly greeting to the astronauts and then displays the temperature in degrees Celsius. If the temperature is warm then it displays a warm picture showing the sun and a smily face, or if it is cold then it displays a snowy scene.

The code has been written in Python. There were some slight modifications used in the video (it included key-presses that allowed the code to be repeated), but the actual code that ran on the Raspberry Pi on the ISS is included below:

from sense_hat import SenseHat
import time
sense = SenseHat()
sense.set_rotation(270)

red=(255, 0, 0)

blue=(10, 0, 255)
sense.show_message("Hello, Astronauts", text_colour=red, scroll_speed=0.05)

sense.show_message("Have a nice day", text_colour=(0, 0, 255), scroll_speed=0.05)

temp = sense.get_temperature()

temp = round(sense.get_temperature(), 1)

time.sleep(1)

sense.show_message("It is " + str(temp) + "Degrees", text_colour=(0, 255, 0), scroll_speed=0.05)

g = (0, 255, 0)
b = (0, 0, 255)
w = (255, 255, 255)
y = (255, 255, 0)
g = (0, 255, 0)
p = (145, 200, 255)

hot = [
  w, w, w, w, w, y, y, y,
  w, b, w, b, w, y, y, y,
  w, b, w, b, w, y, y, y,
  b, w, w, w, b, w, w, w,
  b, w, w, w, b, w, w, w,
  w, b, b, b, w, w, w, w,
  g, g, g, g, g, g, g, g,
  g, g, g, g, g, g, g, g
  ]


cold = [
  p, p, p, p, p, p, p, p,
  p, p, p, p, p, w, p, p,
  p, p, p, w, p, p, p, p,
  p, p, w, p, p, p, p, p,
  p, p, p, p, p, w, p, p,
  p, p, p, p, p, p, p, p,
  w, w, w, w, w, w, w, w,
  w, w, w, w, w, w, w, w
]
  


if temp >= 20:
  sense.set_pixels(hot)
  time.sleep(2)
else:
  sense.set_pixels(cold)
  time.sleep(2)

The children actually wrote more code initially, but it had to be trimmed down to make it simpler due to the restrictions on the project.

Below are some photos of my son with his certificate and of the 2nd page of the certificate showing that the ISS was in orbit above Columbia at the time the code was run.

European Astro Pi Mission Zero certificate - code that was run on the International Space Station (ISS)

Certificate from European Astro Pi Mission Zero project, showing where the ISS was when running the code

OMSCS Studying online – MSc in Computer Science with Georgia Tech

January 24th, 2018

I’ve recently completed an online Master degree with Georgia Tech. This has been a huge commitment in terms of time, but I’ve learned a lot.

Online MSc in Computer Science OMSCS at Georgia Tech

“University Master Degree – same as on-campus but it’s online”

As an online course the cost is only a fraction of on-campus classes, and in my case my employer covered the course fees. The classes are taken at a time that suits the student by following videos online and submitting projects and homework through an online portal. It even replicates the exam environment taking exams with the student monitored by webcam. The final degree certificate is the same as the on-campus degree.

Other than the cost and flexibility of working online the course is the same as those taught at the University so it is not easier or harder than an on-campus course, although it does have some different challenges.

The classes are provides as online videos through Udacity. These are mainly traditional style lecturer and slides, but some include added videos to show real-world examples. Some also include knowledge check quizzes during the classes so that you can check on your learning. These can be watched and re-watched as much as is required and don’t need to follow the pace of the class (although it’s usually a good idea to keep up with the videos). The assessment is then performed based on homework tasks, projects and/or exams. Support is provided to the students through forums (both students-helping-students and with Teaching Assistants supporting the students) and Virtual meetings with the TAs and/or Professor.

There are a few different specializations available and a reasonable amount of choice of classes within them, although some classes are compulsory (such as all specializations needing a theory class). There are around 29 classes at my last count, with more new classes being added each year.

“You don’t need a computing degree, but computing experience and maths knowledge is required”

I was a little concerned about my lack of knowledge when starting the Master degree. Whilst I already have a Master degree it is in electronics rather than computing and whilst I have had plenty of hands-on with computing and programming I did think I may be missing some of the theoretical knowledge around Algorithms. My theoretical maths is also a bit rusty as it is almost 20 years since my first degree. I therefore spent some time reading up on Algorithms prior to starting the course as well as trying to brush-up some of my maths. This paid off as I did well on the theoretical class and got a comfortable B, although not as good as the A I got on the other classes.

I do think it would be advantageous to have studied for a Bachelors level computing degree, it wasn’t necessary with the appropriate experience.

Classes I studied

I chose the specialization of computing systems, which is a fairly generic specialization focussing on operating systems, programming and security.
Below are the courses I took along with a short summary and example of the projects:

CS6250 Computer Networks

An advanced networking course looking at Software Defined Networking. Fortunately I had plenty of experience with computer networking so this was a good starting point, although the detail of Software Defined Networking was new.

This was project and homework based including monitoring and tuning network performance and creating a firewall using Software Defined Networking.

MSc CS6250 project network performance graph

CS6300 Software Development Process

This is a class I was particularly interested to take as whilst I have had a lot of programming experience this has mostly been self-taught and I wanted to understand some of the theory of how to program better. The class didn’t disappoint me and I learnt and awful lot from this one.

The course was project and homework based, mainly using Java and Android programming, which I enjoyed. This included a project for an Electronic Point of Sale system that had to integrate with a (fictional) credit card machine.

UML Diagram created for CS6300 software development process project 2

CS8803-002 Graduate Introduction to Operating Systems (now CS6200)

I’ve always been interested in operating systems and coding close to the hardware. This was a difficult course and had some complex projects based around C programming. It was particularly difficult through a couple of the projects, but it was very worthwhile and I have a much better understanding of programming and how it interacts with the hardware and the operating system.

The projects included writing a file cacheing proxy server in C.

There were also difficult exams as well as the course work.

The word introduction makes this sound like it would be an easier course, but it was just as hard as the advanced operating systems class.

TCP Dump from project 3 of OMSCS Introduction to Operating Systems

CS6210 Advanced Operating Systems

Although the previous class was an “introduction” and this was titled advanced it was on a similar level. The one thing being that it did need some of the knowledge from the previous course. This class included projects using C programming, including parallel processing and synchronisation, as well as exams.

OMSCS CS6210 Advanced Operating System - memory page file homework

CS8803-o04 Embedded Software (now CS6291 Embedded Systems Optimization)

I thought that the name of this was deceiving and I’m glad to see it has now been renamed. I was hoping for a class on writing programs to handle the special cases of programming on embedded systems, but it turned out to be more a course on compiler optimizations. Although it did cover some of the challenges of designing embedded systems including realtime programming, the projects were based around how changes in the compiler and code could result in faster code.

This did use a Raspberry Pi in one of the projects.

Online MSc CS8803 Embedded Software optimizations

CS6035 Introduction to Information Security

Another class that I particularly enjoyed, partly due to my past experience working in IT security, but also because it involved some fun projects. This was still very complex as it involved a required a knowledge of how the computer and operating system worked (so it was good to have taken the operating system courses first). The projects were challenging, but I found rewarding. It included creating a buffer overflow to break into a system, but also how to defend against such attacks.

There was also an online exam.

MSc Computer Science - Introduction to Information Security - Cracking the payroll system

CS6505 Computability, Algorithms & Complexity

This is the hardest class that I took. It required a high level of maths knowledge as well as an understanding of algorithms. The class was completely exam based. I spent a lot of time studying on the course and learned quite a lot, but would have preferred a more practical course on the use of algorithms rather than analysing the computability and complexity. The assessment was exam based, including several exams which had to be handwritten and then scanned into the computer.

This class is compulsory for a number of specialisations including Computing Systems. I received a comfortable pass grade in the end, but I know some other students that dropped the class or didn’t get the pass they needed.

This class is no longer taught having been replaced by a Graduate Algorithms course, which is aimed at making the class more relevant and hopefully improving the pass rate.

Exam from CS6505 algorithms - command and conquer

CS6310 Software Architecture and Design

Like the software development class this is something I was particularly interested in. There were some challenges due to working in teams (which was also the case with the software development class), which was made particularly difficult do to there being a large number of assignments which needed to be completed within a short period of time but these challenges were overcome.

The final project was a class management system application, written in Java using a MySQL database and including Weka Analysis.

GUI Mockup for project for CS6310 Software Architecture and Design

CS6262 Network Security

This is another class that I looked forward to and it was another enjoyable class. It involved looking at possible attacks and defences relating to network based attacks including network scanning, web browser exploits (XSS and Click Jacking) and malware analysis.

It was all project based, some of which I really enjoyed.

Click Jacking example from network security class CS6262 from Georgia Tech OMSCS

CS8803-O07 Cyber-Physical Systems Security

My final Class was Cyber-Physical Systems Security. This class was is mainly about security surrounding electrical systems, but also covered other utilities. It had a number of mini-projects, which were fairly easy and took much less time than the other classes, but also had a difficult exam. Still an interesting class, but not so much as the other security related classes.

Searching the Internet for Webcams - Cyber Physical Systems CS8803 Georgia Tech

“Studying online for a degree introduces some challenges, but also adds many benefits”

With the course being online then there were a number of advantages, such as being able to take the course at a time that suits you and being able to re-watch the lectures, but there were a number of challenges that it introduced.

I took the degree course alongside my full time job and family life as a parent of two children. This meant that a large proportion of my spare time was spent on the course. I tried to do most of the studying during the weekday evenings so that I could spend the weekends with my family, but this didn’t work so well with the team projects.

Whilst it is possible to take multiple classes most students I know took just one or two classes at a time. In my case taking only one class at a time meant that it took 10 terms which is about 3½ years to complete.

“Time zone can add additional challenge, but so too can other responsibilities”

I live in the UK, but Georgia Tech is a University in the USA, with most students being from the US. With a 5 to 8 hour time difference this added some additional challenges around timing. These were overcome, with some flexibility on my behalf as well as my family. For example I sometimes stayed up late (up to the early hours of the morning) to attend an online Office Hour with a TA and would schedule team meetings in my late evening to co-inside with early evening of team mates during the group projects. It was also a problem where virtual meetings would occur during my children’s bedtime, so I would have to try and put them to bed before or after the meetings.

The harder challenge when working in a team was that I preferred to avoid working weekends to spend time with my family, whereas other students would dedicate their weekends to their studies. In this case I would try and contribute towards the project during the week, but would inevitably also end up having to spend time on Hangouts or Skype calls during the weekends, which is one of the sacrifices I had to make.

Like other courses there are sometimes those that will seek to cheat to improve their score, or to avoid doing the set homework. This is a real shame as it could potentially damage the reputation of those that do work honestly. Fortunately there are steps in place and we do hear of people being identified and having their score reset or otherwise punished to prevent this from being a problem.

You may think that being an online course then it would be more open to cheating, but there are checks in place to prevent cheating. This includes AI cheat detection during exams (with manual verification) and checking submitted code for plagiarism. There are ways that students could still attempt to cheat, but this is no different from other courses and it doesn’t appear to be a major problem.

“Some of the classes did have teething troubles”

There were a few issues with classes in particular some assignments. Some of these were technical issues due to the classes being so new (in some cases I was taking the class during it’s first run on the online MSc program). These included problems with the Virtual Machines (most of the project work was in Linux Virtual Machines) or problems with the supplied code. Most of the technical problems were fixed by the students working together. These were a good learning opportunity, although perhaps not directly relevant to the topic at the time.

The other problems that I encountered were due to ambiguities in the assignment instructions. These were usually clarified prior to the due date, but did sometimes result in having to redo parts of the assignment which felt like a waste of time when there was a deadline running.

“How did I do”

In the end I managed to get an A in 9 out of the 10 classes, and a B in one. The US often use a GPA scoure which I achieved 3.9 and as a comparison with a UK that would be the equivalent of a distinction. I am very happy with my achievement which reflects the amount of work that I put into it. It is a difficult course, which I believe is important to maintain the high standard.

There was an option to attend the full graduation ceremony at Georgia Tech. Due to a combination of logistics and the cost of travel from the UK I made the difficult decision not to attend the ceremony. I was a little disappointed by this as it does feel a bit of an anti-climax after all the effort, but I am now eagerly waiting on receiving the certificate when I will take the opportunity to celebrate with my family instead.

Summary

It’s been a great journey. There have been highs with some fun projects and learning great new stuff, but also some low points when I’ve had a deadline to meet or being revising for an exam. In these ways then this is the same way as any University course and the final grade does reflect that. This has been a very difficult course, but in comparison to my previous Master degree I found the long and slow approach useful (taking one class per term) as it meant that I only had to focus on that one subject at a time.

For anyone considering taking a degree like this then you do need to think carefully about how much time you are willing to put in. In my case the impact was not just on me, but also on my family. Fortunately they were supportive of me spending time on my course.

For more details about the course then see the link below:

Note: The images in this post are intentionally small to prevent them from being used by future students, which would be a breach of the Georgia Tech plagiarism rules.

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