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Stewart's Blog

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Why I Scout! – Shirejammin’ at home challenge

May 31st, 2020

On top of my job, family and computing interests I’m also an assistant Cub Scout leader and a member of the District Executive Committee (Charity Trustee of the Scout District). During the current Coronovirus / Covid-19 pandemic we are unable to meet face-to-face but scouting is still happening through virtual conference sessions I am running on a weekly basis and executive meetings which have moved to Zoom.

The local Scout County are also running challenges for members young and adult, including this weeks’ leaders challenge “Why I Scout”. So here’s my story and the reason I am involved with Scouting.

Previous Experience of Scouting

I have been a Scout throughout my youth. I joined the Cubs when I was 8 (they didn’t have the younger Beaver section in those days) and continued up to Venture Scouts (now known as Explorer Scouts). As an explorer I used to help out at the Scout troup (what would now be a Young Leader) and when I went to University I became an assistant Scout leader near my halls of residence. I countinued scouting briefly after leaving university but the meeting night clashed with other activities and due to my other volunteering with St John Ambulance I left scouting for about 15 years.

Why I came back to scouting

I rejoined scouting thanks to my son. He was the one that made me realise what I’d been missing the last few years.

My son joined the local Beaver Scouts, which is something I’d encouraged as I remembered how much I had got from being in Scouts. It was when he moved up to Cubs and I took him to his first Cub camp that I realised that I still had the Scout inside me wanting to get involved. Although I’d never been to that campsite before, the moment I arrived I was transported back to my own experiences of Cubs and Scouts and the fun I’d had.

It actually started with trepidation of dropping my son off for his first camp but when I dropped him off and the Cub leader had him help making a campfire that’s when I realised I didn’t want to drop my son off for a weekend; I wanted to be there with him enjoying the experience myself.

So that was it. It also happened that the group was short of leaders and at the AGM later that year I put my name forward to “help out”. Initially I was planning to be a sectional assistant but after my initial meeting with the training advisor I changed that to assistant cub scout leader. Three and a half years later and I’ve now completed the requirements for my Wood Badge (Scout leader training programme) and I’m still very much enjoying Scouting.

My only regret is that I didn’t get back involved years ago.

What do I get out of Scouting?

Scouting for me is about enjoying the experience as much as giving back to my local community and supporting the young members. It’s an opportunity to meet new people, make new friends, learn new skills and have fun doing so. It’s also great to be able to provide opportunities for the young members and to see them learn new skills and develop in confidence.

Being a scouter is being part of a huge family with members all over the world.

Scout Leader Training location
Scout Leader Training Location

My future in Scouting

Scouting can take up a lot of time (Spoiler alert – it’s more than 1½ hours per week).

Although I am able to find time for scouting, due to family commitments over the last year I have been finding it harder to attend the regular Cub meetings. At least I was prior to lockdown, during lockdown I’ve been running regular meetings for the whole group including the Beavers and Scouts as well as my Cub pack.

One of the good things about scouting is that there are lots of other opportunities for different roles either hands-on with the young members or providing support to those that do. I think my involvement in Scouting will be changing in future I am confident that I will find a suitable role that allows me to continue being a part of the scouting family.

What I’d say to others

If you are wondering whether Scouting could be for you then I suggest you don’t delay and find out today. Get in touch with your local Scout group or through Scouts website. There are always positions available as the more adult volunteers that are involved the more young people that can be supported and the better the opportunities for our youth members.

Scouting hasn’t stopped during lockdown, although it has changed temporarily. It would be a great time to get involved and learn more prior to resumption of normal face-to-face meetings.

Although it can take up lots of time it’s an enjoyable experience. If you can’t make every week then there are opportunities to be an occassional helper or to help behind the scenes in supporting the activities.

Also see

See the following YouTube video for another ShireJammin Challenges I’ve completed.

New Raspberry Pi 4 with 8GB RAM – Use as a desktop PC

May 29th, 2020

The Raspberry Pi is now available with 8GB of RAM. The cost is higher, costing almost twice as much as the 2GB version, although only about £25 more than the 4GB version. The question is what can you do with 8GB of RAM and do you really need that much?

The fact that you can now buy a Raspberry Pi computer with 8GB of memory for $75 is a huge achievement. It’s something that wasn’t possible a few years ago. Whether you need one just yet is up for debate.

Full details are explained in the following video, which shows how I tested this. It’s not quite real world setting, but I’ve tried to at least launch the same applications that you may expect to have running at the same time.

Whilst you are here, please consider subscribing to PenguinTutor on YouTube. The more subscribers I get then I know it’s worth me continuing making videos on my projects. It doesn’t cost you anything to register and subscribe and hopefully you’ll enjoy some of my future videos.

Raspberry Pi 4 8GB edition with two screens

Testing Memory Usage of the Raspberry Pi 4 – 8GB

To perform the test I connected the Raspberry Pi 4 to a NexDock 2, and a computer monitor. A 32GB SD card had the latest Raspberry Pi OS (full install) and the latest updates were installed. I enabled ssh and VNC and used SimpleScreenRecorder to capture the video from the Raspberry Pi NexDock screen.

I launched various office applications, a web browser with a few tabs open and tried OpenShot. I didn’t open many large documents, although I did load some videos into OpenShot and set it rendering the video (I cancelled the video rendering as it woul have taken too long for the video demonstration).

Measured memory usage of Raspberry Pi 4 8GB

In use I didn’t manage to get the memory usage much above 2GB, suggesting that the 4GB version is probably up to most peoples requirements.

CAD on a Raspberry Pi 4

One task that I did think would use more memory is CAD (computer aided design). I did try and run FreeCAD, but that failed. I think this is due to it not working with the OpenGL graphics drivers on the Raspberry Pi. I do think that is one place where the extra memory would be useful. Although not tested in the video Blender could be another one, it does run in a reasonable amount of memory (as I have used Blender on the older versions of the Raspberry Pi), but complex designs may benefit from the extra memory.

I also didn’t try 3D printer slicers. I know that for Cura the latest version is compiled for 64 bit Intel only, but that is something that may be possible in future.

Summary for desktop use of Raspberry Pi 4

Based on this limited testing I don’t think there is a need to have more than 4GB for using a Raspberry Pi as a desktop computer, at the moment.

The testing was not full real-world use and perhaps it may be possible to go beyond 4GB by loading large documents, although I still don’t think that most users will need more than 4GB.

CAD is one area that may benefit, but I was unable to perform the test of FreeCAD for this test.

This may change in future and it can potentially open up new opportunities for the Raspberry Pi. Areas that were previously out-of-bounds for the Raspberry Pi are now becoming possible. Paying an extra $25 for the 8GB version can help future proof your Raspberry Pi.

Non desktop use

Beyond the desktop there are other areas that may make better use of the 8GB of memory on the Raspberry Pi 4. You could perhaps look at using a RAM disk to speed up the Raspberry Pi as well as reducing the amount of writes to the SD card if you have a system that is prone to power loss (eg. a remote monitoring device).

It may also help with running a network server by allowing a large number of server threads or caching database information.

The fact that you can now buy a Raspberry Pi computer with 8GB of memory for $75 is a huge achievement. It’s something that wasn’t possible a few years ago. Whether you need one just yet is up for debate.

Other suggestions

Do you know of any other cases where 8GB RAM would be useful? If so please leave a comment on the Video reviewing the 8GB RAM Raspberry Pi 4.

Creating practical science lessons for home schooling during Covid-19 lockdown

May 13th, 2020

As a STEM ambassador, I’ve done quite a lot of practical science lessons with my children and primary age school children. There are lots of science books that you can get full of experiments that you can do at home. When they reach secondary school it’s a little more difficult without having a science lab at home. Not only do science experiments need special equipment including a bunson burner, but they also need a bunch of chemicals that you can’t just get from your local supermarket (or not in their pure form at least). So about a year ago I subscribed to Mel Chemistry which is a monthly science subscription service. You start with a set of basic equipment and then each month you get a pack containing most of the chemicals you need along with simple step-by-step instructions to complete the experiments (usually two or three related experiments) and an explanation of the science behind them.

Mel Science Kit - Magic Liquid - science experiment for measuring PH of acids and alkalis

I’ve been slowly working through them with my daughter who is very keen on science, but my son hasn’t really taken much interest. That is until today when I was helping my son with science during the coronovirus / covid-19 lockdown and school closures. His lesson included watching some videos and answering some quizzes which he worked through and then I suggested getting out the Mel Science kits and looking for a related experiment. We found two experiments that fitted well which my daughter had done with a friend. As the Mel Science kits include enough of the chemicals to complete the experiments twice we had everything we needed.

The topic my son is covering in science is acids and alkalis and the practical experiments were both around PH indicator which is a perfect fit with the school lesson. The experiements we did were:

Chemistry at Home - Mel Science experiment - Acidic patterns - experiment with acid and alkali chemicals

The experiments are usually easy to do and usually take between about 10 minutes and 40 minutes. Whilst almost everything is provided you do sometimes need to buy some items yourself. One is Hydrogen Peroxide which I already know as something you can buy from most pharmacists (used in elephant toothpaste catalyst experiments I have done with the Cub Scouts). The one thing I still need to find is starch, they sell it in an aerosol at a local supermarket but I’ve not been able to find a suitable source at the moment.

Aside from this little thing the kits have been really good. The experiments have clear instructions and almost always work first time as long as you follow the instructions correctly. It’s been useful to encourage my daughter’s interest in science and even more so with schools closed. I’ve also learnt some more about chemistry as well.

Note: This is purely my own opinion. I have no involvement or affiliation with Mel Chemistry other than as a paying subscriber.

Also see – Mentos and Cola science experiments

Here’s a video I made several years ago of a simple science experiment involving mentos and coke / cola.

Star Wars Day – Raspberry Pi RGB Matrix Display

May 4th, 2020

Today is the 4th May, which means Star Wars day.

Star Wars Day - RGB Matrix - 4th May 2020

So I’ve added a new scrolling image showing a series of images from each of the 9 films in the three trilogies playing on my Raspberry Pi controlled RGB LED Matrix Display. It’s 4946 x 32 pixels long. Shown on my 64 x 32 Matrix Display outside my house. I’m also going to add a light display using my RGB LED NeoPixels (ws2811, ws2812, ws281x LEDs).

The video below is just over 5 minutes long showing the full sequence.

More details see:

@Home activities for children during Covid-19 Coronovirus lockdown

April 10th, 2020

As a parent I understand how important it is to keep children entertained. This is now even harder with the country in lockdown over a sunny Easter holiday. Here are some links to useful activities.

Scouts – The Great Indoors

Scouts is normally considered an outdoor organisation. In fact during leader training Scout leaders are encouraged to aim for about 50% of all activities to be outdoor. That hasn’t stopped them raising up to the challenge of providing fun indoor activities. The Great Indoors is a list of activities and ideas that can be used for all age groups (targetted at age 6 upwards) and are just as useful for parents and children as they are for scouts.

Learn computing and digital making with Raspberry Pi

Book Trust

Some free resources on reading and literacy

Watch a Theatre show or Musical

Some of these may be suitable for older children only.

Keep fit – PE with Joe

A fun workout every weekday morning at 9am, or watch replays when convenient.

More suggestions

Some things you may want to search for using a search engine.

Virtual Zoos and Aquariums – Visit a virtual zoo or aquarium and write a short report or create a postcard

Thank you messages – LED Matrix Display – Coronovirus / Covid-19

April 9th, 2020

I’m writing this post during lockdown in 2020 during the Novel Coronovirus / Covid-19 pandemic.

Before the virus took hold in the UK I’d already started work on Raspberry Pi Outdoor Display (RGB LED Matrix) and Handrail Lighting (NeoPixels) Project. The idea was an extension of a light display I was planning to add to my Christmas Lighting display. I then planned to display messages on special events such as St George’s Day and Easter etc.
When the lockdown started we found ourselves very much dependant upon the bravery and generosity of key workers and volunteers striving to keep everyone safe. I therefore decided to repupose the LED Matrix display to send thank you messages to various key workers helping to support the community and keep us safe. I’ve also added some friendly messages and suggestions for things to do indoors.

Raspberry Pi RGB Matrix Display with Thank you NHS message

These are some of the videos of displays that I have shown.

Day 1 – The NHS

The National Health Service is a large organisation from doctors and nurses working directly with those with the Virus, to the adminstration staff and cleaners without whom the NHS would not be able to function. This is a thank you to everyone working in the NHS whatever their role.

Thank You NHS - Covid-19 Coronovirus message

Day 2 – Shop Workers

It quickly became clear that as a nation we are very much depedant upon shops, and the staff in those shops, so that people can buy food and essentials. These have become key workers that are dealing directly with the public and so are at an increased risk of catching the virus. Where possible existing staff have continued to work, to ensure that people are fed and to support their communities. Many other people have taken short term work to help as well. In addition to those those in traditional stores where some shops have had to close down many have kept their online stores running to support people stuck at home including deliveries of educational materials and other products to keep businesses running and people occupied.

Thank you shop workers - Covid-19 Coronovirus message

Day 3 – Lorry Drivers

Without the lorry drivers then they’d be nothing in our shops. So this message thanks them, the often unforgotten workers that keep the food supply chain working.

Thank you lorry drivers - Covid-19 Coronovirus message

Day 4 – Happy Easter

The real reason I started creating the matrix display was to show topical messages, such as this Easter message. Whilst much has changed since then the message wishing everyone Happy Easter is still the same. I’ve added some eggs as well for those that may be following a local neighbourhood Easter Egg Game as suggested by the New Zealand Prime Minister for those unable to take part in a real Easter Egg Hunt due to the current situation.

Happy Easter - RGB LED Matrix display

Day 5 – Ambulance and Air Ambulance

I added an extra message for the Ambulance and Air Ambulance services who are responding to emergencies to people when they become sick.

Ambulance and Air Ambulance thank you messages for Covid-19 coronovirus

Day 6 – Key workers

A thank you for all key workers, whether they are in the medical profession, postal services, keeping our food supply chain running, keeping the Internet and computer networks running, keeping our lights on (electricity company) or helping support our children in education. Many people that are essential to keeping the country operating in the difficult situation.

Key worker thank you messages for Covid-19 coronovirus

Day 7 – Postal and delivery workers

Our postal workers continue to work each day delivering post and parcels and messages from loved ones you cannot see. Also to all those working to deliver goods from online retailers and needed supplies.

Postal and delivery worker thank you messages for Covid-19 coronovirus

Day 8 – Refuse workers

People are still generating rubbish which needs to be disposed of. With some waste and recycling sites closed to the public it is critically important that our bins still get emptied on a weekly basis.

Refuse workers thank you message for Covid-19 coronovirus

Day 9 – Clap for carers

Actually split between day 8 and day 9 (due Thursday Clap for Carers) this is a thank you for those working in the NHS, but also other medical or caring professions including nursing homes, or those working behind the scenes in testing labs, cleaning staff and admin roles to look after those in need.

Clap for carers thank you message for Covid-19 coronovirus

Day 10 – Volunteers

Members of the public volunteering to support others during this time. This includes the additional volunteers that support the NHS, but also existing volunteers such as St. John Ambulance, Food banks and youth organisations such as the Scouts and Guides who are still helping to support young people through virtual activities.

Volunteers thank you message for Covid-19 coronovirus

Day 11 – Emergency Services

Another thank you to the emergency services, including a fire engine and a police car alongside the ambulance used previously.

999 Emergency Services thank you message for Covid-19 coronovirus

More coming soon

Please visit this page again to see the new messages.

Linux printer cupsd broke plasma on Kubuntu 19.10 – no start menu

April 5th, 2020

Kubuntu KDE printer settings
I’ve just had a problem with Kubuntu where the start menu didn’t appear. So it was not possible to launch applications, or pretty much do anything. For anyone that has a similar problem this is how I fixed it.

First identify the problem.

To be able to do some diagnosis you need a shell. To launch Konsole press CTRL - Alt - T

Plasma is the name of the KDE desktop environment that Ubuntu uses. The Plasma shell provides the start menu and handles other tasks associated with the desktop. I there tried to start plasma using plasmashell which failed.
There were a lot of messages, but significantly it broke shortly after a reference to cupsd. CUPS (formally known as Common UNIX Printing System) is responsible for handling printing from Linux. So I stopped Cups using
sudo service cupsd stop
then ran
plasmashell
and this time it worked.

I also want to be able to print so I started the printer configuration page, and restarted cups sudo service cupsd start. This broke plasma again, but I now hand the printer configuration page that allowed me to delete the printer drivers. That alone didn’t fix it, although I didn’t investigate further as at this point I decided to take a forceful approach of reinstalling the entire printer setup. I removed it using
sudo apt remove print-manager
then reinstalled using
sudo apt install print-manager

I re-added my printer through the printer configuration menu, rebooted and it’s now fixed. It turns out this a problem that other have had before, so I thought I’d put it here in case someone else has the same problem. The next version of Kubuntu will be version 20.04 which is due later this month, so it would be interesting to know if they have added a fix so that plasmashell doesn’t crash even if there is a problem with the printers.

Videos and Tutorials on Game Programming with Pygame Zero

April 2nd, 2020


I’ve recently published a book Beginning Game Programming with Pygame Zero.

To accompany the book I’ve created some videos showing some of the games that you can create and some of the techniques that have been covered in the book. I’ve also created some other videos and tutorials that are not directly related to the book which explain some of the techniques as well. Here are some of those videos …

Beginning Game Programming with Pygame Zero

This is a video showing the variety of different games in the book.

Complete Beginners Guide

Here is a worksheet for creating a first game in Pygame Zero

This video provides an introduction to getting started with Pygame Zero, including creating a first window and creating an animated character on the screen.

Creating Vector Images for Computer Games in Pygame Zero

How to create vector images in Pygame Zero. Vector images are created from shapes. This uses rectangles, elipses and polygons to create a tank used in a tank battle game. Two tanks then battle it out creating a trajectory for the shells to try and hit their opponent.

Using Object Oriented Programming (OOP) for Computer Game Programming with Python Pygame Zero

Object Orinented Programming is a useful technique for creating any computer programs. This video shows how those techniques can be applied in Python and Pygame Zero to create a matching pairs memory game.

Creating an Artificial Intelligence (AI) Opponent for Computer Games in Pygame Zero

For many games the enjoyment is in playing against a computer opponent which has the right level of ability. It needs to be difficult enough to provide a challenge without being so difficult you always lose. This looks at some techniques of creating an opponent using simple AI.

Part 1 uses the same matching pairs memory as the previous video on object-oriented programming, but creating a computer opponent with different levels of difficulty.

Part 2 looks at how you people play the classic Battleship Game to create a computer opponent that provides a good level of difficulty.

Using a USB controller / joystick with Pygame Zero and QJoyPad

For more information on how to play Pygame Zero games using a USB game controller or joystick see the guide: Using a gamepad or joystick on a Raspberry Pi with Python Pygame Zero

Space Shooter Game

The final game is a Space Shooter game. It combines many of the techniques already learned to create a playable game. The video below gives an explanation for some of the additional features used to create the game.

Game using electronics, physical computing and Pygame Zero

Pygame Zero for makers

Includes the following video on controlling lighting for a 3D printed Christmas House

Also see:

New Book – Beginning Game Programming with Pygame Zero

February 14th, 2020

Beginning Game Programming with Pygame Zero book
This is my second professionally published book, published by Apress.
Beginning Game Programming with Pygame Zero.

The is a fun way to learn computer programming by creating computer games. This is designed as a book to give you all the skills you need to start programming your own games, from designing the game, creating the graphics, designing sound effects and programming using Pygame Zero. It’s designed for use on a Raspberry Pi, but you can also code on any other computer which has Pygame Zero installed.

You can see my introductory video below.

More information for Beginning Game Programming with Pygame Zero

NexDock 2 – Laptop style screen and keyboard for Raspberry Pi or mobile phones

January 7th, 2020

A few years ago I backed a Kickstarter project for the original NexDock for use with the Raspberry Pi. Last year they created an updated version called the NexDock 2. A new improved version.

NexDock - laptop style dock without a processor

You can see my NexDock 2 unboxing and review video here, or read on for more information.

What is a NexDock?

A NexDock looks like a laptop, but it’s missing one thing, a processor. It has a screen, keyboard (with touchpad) and battery in a laptop style shell. It cannot work as a laptop until you connect it to a computer.

So what’s it used for? Well most people now carry a fairly powerful computer in our pocket, it’s a mobile phone and the two things that stop it being used as a computer are a decent sized screen and a keyboard. Put the two together and you have what is effectively a full computer. That is one way that I’ve used the NexDock but for more I found it particularly useful when used in combination with a Raspberry Pi. It provides a quick and easy way to connect to a Raspberry Pi which may be embedded in a Robot, inside a model house, or even in a wearable snowman badge.

NexDock 2 with a mobile phone – Samsung S8 Dex

Firstly I tried by connecting it to a mobile phone. It works with a number of Android phones with a USB-C connector, in my case a Samsung G8. The Samsung phone includes Dex which provides a full laptop like environment which works well with the phone. Many apps can expand to use the full screen, although not all Android apps support that. The main thing for me is that it allows you to send emails or write documents using a keyboard instead of the on-screen keyboard.

NexDock 2 - using a Samsung Phone (G8 or later) as a computer using Dex (USB-C)

NexDock 2 with a Raspberry Pi

The NexDock 2 appears to work with all versions of the Raspberry Pi. This is an improvement over the earlier NexDock which struggled with the Raspberry Pi Zero. Also the NexDock 2 no longer uses Bluetooth so you don’t need to find a temporary keyboard whenever the bluetooth fails to connect. This does mean that you have to connect a physical cable for the keyboard to work, but then you have to use a HDMI cable anyway. This is a big improvement on the older NexDock.

NexDock 2 - using a NexDock as the screen and keyboard for a Raspberry Pi laptop style

Supplied cables and accessories

There is a good selection of supplied cables and adapters as shown in the photo below:

Cables and accesssories supplied with the NexDock 2

The NexDock 2 is powered from a USB-C charger which is included along with different adapters for different country sockets (a big improvement on the travel adapter supplied with the previous version). It also includes all the cables that you will need to connect to a USB-C smartphone, Raspberry Pi (1 to 3) and Raspberry Pi 4. If using a Raspberry Pi Zero then you will need to source your own mini-HDMI to HDMI adapter (or cable) and a micro-USB OTG adapter, however most people with a Pi Zero will likely have these already. The cables are all fairly short, which should work with it’s designed use, but it’s easy enough to provide your own longer cables if you need anything extra.

Any issues?

So far I haven’t come across any major issues. It appears to work with my mobile phone and different versions of the Raspberry Pi.
If there was one thing I would change it would be to include a UK keyboard layout. I accept this is difficult to do on a Kickstarter project, but it would be a big improvement. The reason being that when using a Raspberry Pi then you may need to make use of some of the special characters that need different key combinations. Changing the keyboard layout each time you connect a NexDock versus a UK keyboard is a bit of a pain. For me the main thing is some of the keys used on the Linux command line which I had to find through trial and error.

Other than that any other things are very minor.

Summary

I don’t use the mobile phone Dex very often, but that is a useful thing to have. For me the main reason for the NexDock 2 is to connect to a Raspberry Pi either during initial setup or when it’s connected as part of a project. For that the NexDock 2 is great. It provides a reliable keyboard and screen which is much easier than lugging a standard monitor around. It also includes a built-in battery which can even power the Raspberry Pi.

If you regularly need to connect to a Raspberry Pi when you don’t have a screen to hand then I highly recommend getting a NexDock 2.

Missed the Kickstarter? You can pre-order using the link below.

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