Category Archives: Computer Science

Extract RGB Values from an Image

Our Head of Physics today asked me if there was any code we could use that would demonstrate to his A-Level Physics students the way that digital images are represented by red, green and blue pixels with a value between 0 and 255. The reason is because of the introduction of a digital imaging unit within the new A-Level specification, and whilst this could be taught as pure theory he felt a working example to illustrate the point might help.

This got me thinking and after a bit of searching I found a Stack Overflow post which gave an example of retrieving a single pixel’s RGB value and printing it out.

This example makes use of the PIL python library, which unfortunately has not been updated for Python 3. However we can make use of the Pillow library in Python 3 to achieve the same thing!

The image I have used in the code is this one:landscape

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Embed a Twitter Feed into Moodle

In a recent #NT2tEU Twitter chat someone posed the question about how you link Twitter and Moodle together. There were suggestions about using your Twitter account to post messages about upcoming events and assignments in Moodle, linking back to them with the URL.

The way I tend to use Twitter and Moodle together is the other way round. I let Moodle take care of sending out the emails it needs for notifications, and I use Twitter as a way of pulling interesting feeds of information back into my Moodle courses.

To do this we are going to set up a Twitter Widget and then embed this code into a HTML block on our Moodle course page

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Raspberry Jam Logo

Hull Raspberry Jam – 23rd April 2016

This weekend I was lucky enough to be involved with hosting the second Raspberry Pi Jam event that Hull has seen. Through Twitter, Claire Garside and myself got talking and a tweet of my Raspberry Pi robot I was building one weekend, led to a discussion about re-igniting the Raspberry Jam events in Hull.

Thanks must go to Claire and the Leeds Raspberry Jam team for the loan of all the equipment which allowed our event to go ahead. Thanks also must go to Malet Lambert and Stephen Logan for allowing us to use their space.

The event kicked off with an introduction to the Raspberry Pi and allowed people to get hands on setting up their Pi and getting everything running. They then had a chance to hack a Scratch game and try to improve it.

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#Picademy Day 2 – The results

So as I went into day 2 of #Picademy I had decided upon a “motion activated camera which tweets the photo taken along with a random poem, giving you a LED countdown indicator” for my project.

Some of this I had previously coded (the random poem part) which you can see running in this Trinket app below:

My thoughts were that I could make use of this to create the text of my tweet adding the #Picademy hashtag to the end too.

Continue reading #Picademy Day 2 – The results

#Picademy – Day 2 Planning

So after day one of #Picademy my evening was spent thinking about, and reading about what I could do for my project on day 2.

My initial thoughts was to use a USB microphone to get an audio feed into a Raspberry Pi to then try and use Python to “listen” to the microphone and react to different audio levels coming in; a kind of graduated analogue switch if you like… So between #Picademy finishing and meeting up for the evening meal I spent my time walking (quickly!) around Manchester trying to find a shop selling basic USB microphones; to no avail!

So over the evening meal I was discussing this idea more with Les and we thought it maybe possible to use the Jack Audio Server to flip the Pi’s inbuilt headphone jack into a microphone jack. This is possible on Ubuntu, as a quick search on our phones verified; so I thought we were on to a winner here. However after a little playing around with my Pi back at the hotel, it turns out that the HDA-Jack-Retask application just does not work with the Raspberry Pi soundcard 🙁

This left me back at square one… What do to on day 2?

So I wake with this thought… “A motion activated camera which tweets the photo taken along with a random poem, giving you a LED countdown indicator” – Should be easy!

Watch this space for progress!

#Picademy – Day One

This February I was one of the lucky few to be accepted on the Picademy event at Google’s Digital Garage in Manchester. More details about the event can be found here: https://www.raspberrypi.org/picademy/google/manchester/

This post is a summary of my thoughts after day one – more as a memorandum for me than anything else. Apologies if I have forgotten any of the sessions or put them in the wrong order; to coin a phrase used in the training, I reached “cognitive overload” fairly quickly!

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Christmas Sonic Pi

This week my Year 8 class asked if they could do something festive with me for their last lesson before we break up next week. Now I am not a believer in stopping work just because it is the last week of term, but I thought I could probably give them a Computer Science lesson and easily add a Christmas theme to get the best of both worlds. I gave them the choice of either using Python Turtle art to create festive pictures, or use Sonic Pi to “code” some Christmas music.

The class went for Sonic Pi; so I thought I would share my lesson plan here.

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Hello Minecraft World!

Minecraft screen shots with your Raspberry Pi

We are just about to begin teaching our Python and Minecraft unit at school so I began testing everything out on our latest Raspberry Pi image to make sure we were ready for the lessons and adjust any of the lesson plans if necessary.

Our latest Raspberry Pi image runs Jessie. Now one of the improvements Jessie brings us is that the Print Screen button on your keyboard has been set up to run Scrot in the background to save a png screen shot into your home directory. You can read more about it here.

Now that is great as for quite some time taking a screen shot on your Raspberry Pi involved installing Scrot and then running it from the terminal; not the most user-friendly way to get students to take screen shots!

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Getting your Raspberry Pi to update through your school firewall

I have seen many posts on both Twitter and CAS about teachers having issues getting their class Raspberry Pis to update and install software through their school firewalls, so I thought I would share the simple solution that I have implemented at my school.

It actually leverages something that I put in place for our Ubuntu Linux servers, but works just as well for Raspberry Pi devices too.

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