Raspberry Pi powered e-paper display takes months to show a movie

We loved the filmic flair of Tom Whitwell‘s super slow e-paper display, which takes months to play a film in full.

Living art

His creation plays films at about two minutes of screen time per 24 hours, taking a little under three months for a 110-minute film. Psycho played in a corner of his dining room for two months. The infamous shower scene lasted a day and a half.

Tom enjoys the opportunity for close study of iconic filmmaking, but you might like this project for the living artwork angle. How cool would this be playing your favourite film onto a plain wall somewhere you can see it throughout the day?

The Raspberry Pi wearing its e-Paper HAT

Four simple steps

Luckily, this is a relatively simple project – no hardcore coding, no soldering required – with just four steps to follow if you’d like to recreate it:

  1. Get the Raspberry Pi working in headless mode without a monitor, so you can upload files and run code
  2. Connect to an e-paper display via an e-paper HAT (see above image; Tom is using this one) and install the driver code on the Raspberry Pi
  3. Use Tom’s code to extract frames from a movie file, resize and dither those frames, display them on the screen, and keep track of progress through the film
  4. Find some kind of frame to keep it all together (Tom went with a trusty IKEA number)
Living artwork: the Psycho shower scene playing alongside still artwork in Tom’s home

Affordably arty

The entire build cost £120 in total. Tom chose a 2GB Raspberry Pi 4 and a NOOBS 64gb SD Card, which he bought from Pimoroni, one of our approved resellers. NOOBS included almost all the libraries he needed for this project, which made life a lot easier.

His original post is a dream of a comprehensive walkthrough, including all the aforementioned code.

2001: A Space Odyssey would take months to play on Tom’s creation

Head to the comments section with your vote for the creepiest film to watch in ultra slow motion. I came over all peculiar imaging Jaws playing on my living room wall for months. Big bloody mouth opening slooooowly (pales), big bloody teeth clamping down slooooowly (heart palpitations). Yeah, not going to try that. Sorry Tom.

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Raspberry Pi turns retro radio into interactive storyteller

8 Bits and a Byte created this voice-controllable, interactive, storytelling device, hidden inside a 1960s radio for extra aesthetic wonderfulness.

A Raspberry Pi 3B works with an AIY HAT, a microphone, and the device’s original speaker to run chatbot and speech-to-text artificial intelligence.

This creature is a Bajazzo TS made by Telefunken some time during the 1960s in West Germany, and this detail inspired the espionage-themed story that 8 Bits and a Byte retrofitted it to tell. Users are intelligence agents whose task is to find the evil Dr Donogood.

The device works like one of those ‘choose your own adventure’ books, asking you a series of questions and offering you several options. The story unfolds according to the options you choose, and leads you to a choice of endings.

In with the new (Raspberry Pi tucked in the lower right corner)

What’s the story?

8 Bits and a Byte designed a decision tree to provide a tight story frame, so users can’t go off on question-asking tangents.

When you see the ‘choose your own adventure’ frame set out like this, you can see how easy it is to create something that feels interactive, but really only needs to understand the difference between a few phrases: ‘laser pointer’; ‘lockpick’; ‘drink’; take bribe’, and ‘refuse bribe’.

How does it interact with the user?

Skip to 03mins 30secs to see the storytelling in action

Google Dialogflow is a free natural language understanding platform that makes it easy to design a conversational user interface, which is long-speak for ‘chatbot’.

There are a few steps between the user talking to the radio, and the radio figuring out how to respond. The speech-to-text and chatbot software need to work in tandem. For this project, the data flow runs like so:

1: The microphone detects that someone is speaking and records the audio.

2-3: Google AI (the Speech-To-Text box) processes the audio and extracts the words the user spoke as text.

4-5: The chatbot (Google Dialogflow) receives this text and matches it with the correct response, which is sent back to the Raspberry Pi.

6-7: Some more artificial intelligence uses this text to generate artificial speech.

8: This audio is played to the user via the speaker.

Make sure to check out more of 8 Bits and a Byte’s projects on YouTube. We recommend Mooomba the cow roomba.

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App note: Impedance characteristics of bypass capacitor

App note from ROHM Semiconductors about different type of bypass capacitors impedance and some tip when replacing them. Link here (PDF)

There are various types of capacitors. If you select parts only based on their capacitance values, the requirements for bypass capacitors may not be satisfied, leading to malfunction of devices or nonconformity to standards. This application note focuses on the impedance characteristics of capacitors, and explains cautions for selecting bypass capacitors.

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App note: BA1117 dropout voltage

App note from ROHM Semiconductors about linear regulator dropout voltage. Link here (PDF)

The dropout voltage is the difference between the input and output voltages that is necessary for the stabilizing operation of a linear regulator. When the input voltage approaches the output voltage, stabilizing operation cannot be maintained and the output starts dropping in proportion to the input. The voltage at which this situation starts, i.e., the difference between the input and output voltages that is necessary for the stabilizing operation, is referred to as the dropout voltage.

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Code a GUI live with Digital Making at Home

This week, we’re introducing young people around the world to coding GUIs, or graphical user interfaces. Let them tune in this Wednesday at 5.30pm BST / 12.30pm EDT / 10.00pm IST for a fun live stream code-along session with Christina and special guest Martin! They’ll learn about GUIs, can ask us questions, and get to code a painting app.

For beginner coders, we have our Thursday live stream at 3.30pm PDT / 5.30pm CDT / 6.30pm EDT, thanks to support from Infosys Foundation USA! Christina will share more fun Scratch coding for beginners.

Now that school is back in session for many young people, we’ve wrapped up our weekly code-along videos. You and your children can continue coding with us during the live stream, whether you join us live or watch the recorded session on-demand. Thanks to everyone who watched our more than 90 videos and 45 hours of digital making content these past month!

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Build an arcade cabinet | Hackspace 35

Games consoles might be fast and have great graphics, but they’re no match for the entertainment value of a proper arcade machine. In this month’s issue of Hackspace magazine, you’re invited to relive your misspent youth with this huge build project.

There’s something special about the comforting solidity of a coin-eating video game monolith, and nothing screams retro fun like a full-sized arcade cabinet sitting in the corner of the room. Classic arcade machines can be a serious investment. Costing thousands of pounds and weighing about the same as a giant panda, they’re out of reach for all but the serious collector. Thankfully, you can recreate that retro experience using modern components for a fraction of the price and weight.

An arcade cabinet is much easier to make than you might expect. It’s essentially a fancy cupboard that holds a monitor, speakers, a computer, a keyboard, and some buttons. You can make your own cabinet using not much more than a couple of sheets of MDF, some clear plastic, and a few cans of spray paint.

If you want a really authentic-looking cabinet, you can find plenty of plans and patterns online. However, most classic cabinets are a bit bigger than you might remember, occupying almost a square metre of floor space. If you scale that down to approximately 60 cm2, you can make an authentic-looking home arcade cabinet that won’t take over the entire room, and can be cut from just two pieces of 8 × 4 (2440 mm × 1220 mm) MDF. You can download our plans, but these are rough plans designed for you to tweak into your own creation. A sheet of 18 mm MDF is ideal for making the body of the cabinet, and 12 mm MDF works well to fill in the front and back panels. You can use thinner sheets of wood to make a lighter cabinet, but you might find it less sturdy and more difficult to screw into.

The sides of the machine should be cut from 18 mm MDF, and will be 6 feet high. The sides need to be as close to identical as possible, so mark out the pattern for the side on one piece of 18 mm MDF, and screw the boards together to hold them while you cut. You can avoid marking the sides by placing the screws through the waste areas of the MDF. Keep these offcuts to make internal supports or brackets. You can cut the rest of the pieces of MDF using the project plans as a guide. 

Why not add a coin machine for extra authenticity

Attach the side pieces to the base, so that the sides hang lower than the base by an inch or two. If you’re more accomplished at woodworking and want to make the strongest cabinet possible, you can use a router to joint and glue the pieces of wood together. This will make the cabinet very slightly narrower and will affect some measurements, but if you follow the old adage to measure twice and cut once, you should be fine. If you don’t want to do this, you can use large angle brackets and screws to hold everything together. The cabinet will still be strong, and you’ll have the added advantage that you can disassemble it in the future if necessary.

Keep attaching the 18 mm MDF pieces, starting with the top piece and the rear brace. Once you have these pieces attached, the cabinet should be sturdy enough to start adding the thinner panels. Insetting the panels by about an inch gives the cabinet that retro look, and also hides any design crimes you might have committed while cutting out the side panels.

The absolute sizing of the cabinet isn’t critical unless you’re trying to make an exact copy of an old machine, so don’t feel too constrained by measuring things down to the millimetre. As long as the cabinet is wide enough to accept your monitor, everything else is moveable and can be adjusted to suit your needs.

Make it shiny

You can move onto decoration once the cabinet woodwork is fitted together. This is mostly down to personal preference, although it’s wise to think about which parts of the case will be touched more often, and whether your colour choices will cause any problems with screen reflection. Matt black is a popular choice for arcade cabinets because it’s non-reflective and any surface imperfections are less noticeable with a matt paint finish.

Aluminium checker plate is a good way of protecting your cabinet from damage, and it can be cut and shaped easily.

Wallpaper or posters make a great choice for decorating the outside of the cabinet, and they are quick to apply. Just be sure to paste all the way up to the edge, and protect any areas that will be handled regularly with aluminium checker plate or plastic sheet. The edges of MDF sheets can be finished with iron-on worktop edging, or with the chrome detailing tape used on cars. You can buy detailing tape in 12 mm and 18 mm widths, which makes it great for finishing edges. The adhesive tape provided with the chrome edging isn’t always very good, so it’s worth investing in some high-strength, double-sided clear vinyl foam tape.

You’ve made your cabinet, but it’s empty at the moment. You’re going to add a Raspberry Pi, monitor, speakers, and a panel for buttons and joysticks. To find out how, you can read the full article in HackSpace magazine 35.  

Get HackSpace magazine 35 Out Now!

Each month, HackSpace magazine brings you the best projects, tips, tricks and tutorials from the makersphere. You can get it from the Raspberry Pi Press online store, The Raspberry Pi store in Cambridge, or your local newsagents.

Each issue is free to download from the HackSpace magazine website.

If you subscribe for 12 months, you get an Adafruit Circuit Playground Express , or can choose from one of our other subscription offers, including this amazing limited-time offer of three issues and a book for only £10!

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Supercapacitor uninterruptable power supply (UPS) for Raspberry Pi

smbakeryt built a couple supercapacitor uninterruptible power supply (UPS) prototypes for his raspberry pi projects:

For my Convergent restoration, I decided to build an RASCSI to replace some failing SCSI hard drives. The RASCSI is a SCSI emulator built using a raspberry pi. Problem with these types of emulators is that if you carelessly power off the host computer (which was a perfectly acceptable thing to do back in the 80s), you end up also unsafely shutting down the pi — which can cause corruption of the SD-Card, loss of in-memory data, etc.
Back when I built David Gesswein’s MFM Emulator, he included a supercapacitor UPS that provided power just long enough to safely shut down a beaglebone. I figured the same thing would work for a raspberry pi.

Project info at smbaker.com.

Check out the video after a break.

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How is computing taught in schools around the world?

Around the world, formal education systems are bringing computing knowledge to learners. But what exactly is set down in different countries’ computing curricula, and what are classroom educators teaching? This was the topic of the first in the autumn series of our Raspberry Pi research seminars on Tuesday 8 September.

A glowing globe floating above an open hand in the dark

We heard from an international team (Monica McGill , USA; Rebecca Vivian, Australia; Elizabeth Cole, Scotland) who represented a group of researchers also based in England, Malta, Ireland, and Italy. As a researcher working at the Raspberry Pi Foundation, I myself was part of this research group. The group developed METRECC, a comprehensive and validated survey tool that can be used to benchmark and measure developments of the teaching and learning of computing in formal education systems around the world. Monica, Rebecca, and Elizabeth presented how the research group developed and validated the METRECC tool, and shared some findings from their pilot study.

What’s in a curriculum? Developing a survey tool

Those of us who work or have worked in school education use the word ‘curriculum’ frequently, although it’s an example of education terminology that means different things in different contexts, and to different people. Following Porter and Smithson (2001)1, we can distinguish between the intended curriculum and the enacted curriculum:

  • Intended curriculum: Policy tools as curriculum standards, frameworks, or guidelines that outline the curriculum teachers are expected to deliver.
  • Enacted curriculum: Actual curricular content in which students engage in the classroom, and adopted pedagogical approaches; for computer science (CS) curricula, this also includes students’ use of technology, physical computing devices, and tools in CS lessons.

To compare the intended and enacted computing curriculum in as many countries as possible, at particular points in time, the research group Monica, Rebecca, Elizabeth, and I were part of developed the METRECC survey tool.

A classroom of students in North America

METRECC stands for MEasuring TeacheREnacted Computing Curriculum. The METRECC survey has 11 categories of questions and is designed to be completed by computing teachers within 35–40 minutes. Following best practice in research, which calls for standardised research instruments, the research group ensured that the survey produces valid, reliable results (meaning that it works as intended) before using it to gather data.

Using METRECC in a pilot study

In their pilot study, the research group gathered data from 7 countries. The intended curriculum for each country was determined by examining standards and policies in place for each country/state under consideration. Teachers’ answers in the METRECC survey provided the countries’ enacted curricula. (The complete dataset from the pilot study is publicly available at csedresearch.org, a very useful site for CS education researchers where many surveys are shared.)

Two girls coding at a computer under supervision of a female teacher

The researchers then mapped the intended to the enacted curricula to find out whether teachers were actually teaching the topics that were prescribed for them. Overall, the results of the mapping showed that there was a good match between intended and enacted curricula. Examples of mismatches include lower numbers of primary school teachers reporting that they taught visual or symbolic programming, even though the topic did appear on their curriculum.

A table listing computer science topics
This table shows computer science topic the METRECC tool asks teachers about, and what percentage of respondents in the pilot study stated that they teach these to their students.

Another aspect of the METRECC survey allows to measure teachers’ confidence, self-efficacy, and self-esteem. The results of the pilot study showed a relationship between years of experience and CS self-esteem; in particular, after four years of teaching, teachers started to report high self-esteem in relation to computer science. Moreover, primary teachers reported significantly lower self-esteem than secondary teachers did, and female teachers reported lower self-esteem than male teachers did.

Adapting the survey’s language

The METRECC survey has also been used in South Asia, namely Bangladesh, Nepal, Pakistan, and Sri Lanka (where computing is taught under ICT). Amongst other things, what the researchers learned from that study was that some of the survey questions needed to be adapted to be relevant to these countries. For example, while in the UK we use the word ‘gifted’ to mean ‘high-attaining’, in the South Asian countries involved in the study, to be ‘gifted’ means having special needs.

Two girls coding at a computer under supervision of a female teacher

The study highlighted how important it is to ensure that surveys intended for an international audience use terminology and references that are pertinent to many countries, or that the survey language is adapted in order to make sense in each context it is delivered. 

Let’s keep this monitoring of computing education moving forward!

The seminar presentation was well received, and because we now hold our seminars for 90 minutes instead of an hour, we had more time for questions and answers.

My three main take-aways from the seminar were:

1. International collaboration is key

It is very valuable to be able to form international working groups of researchers collaborating on a common project; we have so much to learn from each other. Our Raspberry Pi research seminars attract educators and researchers from many different parts of the world, and we can truly push the field’s understanding forward when we listen to experiences and lessons of people from diverse contexts and cultures.

2. Making research data publicly available

Increasingly, it is expected that research datasets are made available in publicly accessible repositories. While this is becoming the norm in healthcare and scientific, it’s not yet as prevalent in computing education research. It was great to be able to publicly share the dataset from the METRECC pilot study, and we encourage other researchers in this field to do the same. 

3. Extending the global scope of this research

Finally, this work is only just beginning. Over the last decade, there has been an increasing move towards teaching aspects of computer science in school in many countries around the world, and being able to measure change and progress is important. Only a handful of countries were involved in the pilot study, and it would be great to see this research extend to more countries, with larger numbers of teachers involved, so that we can really understand the global picture of formal computing education. Budding research students, take heed!

Next up in our seminar series

If you missed the seminar, you can find the presentation slides and a recording of the researchers’ talk on our seminars page.

In our next seminar on Tuesday 6 October at 17:00–18:30 BST / 12:00–13:30 EDT / 9:00–10:30 PT / 18:00–19:30 CEST, we’ll welcome Shuchi Grover, a prominent researcher in the area of computational thinking and formative assessment. The title of Shuchi’s seminar is Assessments to improve student learning in introductory CS classrooms. To join, simply sign up with your name and email address.

Once you’ve signed up, we’ll email you the seminar meeting link and instructions for joining. If you attended this past seminar, the link remains the same.


1. Andrew C. Porter and John L. Smithson. 2001. Defining, Developing and Using Curriculum Indicators. CPRE Research Reports, 12-2001. (2001)

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Raspberry Pi enables world’s smallest iMac

This project goes a step further than most custom-made Raspberry Pi cases: YouTuber Michael Pick hacked a Raspberry Pi 4 and stuffed it inside this Apple lookalike to create the world’s smallest ‘iMac’.

Michael designed and 3D printed this miniature ‘iMac’ with what he calls a “gently modified” Raspberry Pi 4 at the heart. Everything you see is hand-painted and -finished to achieve an authentic, sleek Apple look.

This is “gentle modification” we just mentioned

Even after all that power tool sparking, this miniature device is capable of playing Minecraft at 1000 frames per second. Michael was set on making the finished project as thin as possible, so he had to slice off a couple of his Raspberry Pi’s USB ports and the Ethernet socket to make everything fit inside the tiny, custom-made case. This hacked setup leaves you with Bluetooth and wireless internet connections, which, as Michael explains in the build video, “if you’re a Mac user, that’s all you’re ever going to need.”

We love watching 3D printer footage set to relaxed elevator music

This teeny yet impactful project has even been featured on forbes.com, and that’s where we learned how the tightly packed tech manages to work in such a restricted space:

“A wireless dongle is plugged into one of the remaining USB ports to ensure it’s capable of connecting to a wireless keyboard and mouse, and a low-profile ribbon cable is used to connect the display to the Raspberry Pi. Careful crimping of cables and adapters ensures the mini iMac can be powered from a USB-C extension cable that feeds in under the screen, while the device also includes a single USB 2 port.”

Barry Collins | forbes.com

The maker also told forbes.com that this build was inspired by an iRaspbian software article from tech writer Barry Collins. iRaspbian puts a Mac-like interface — including Dock, Launcher and even the default macOS wallpaper — on top of a Linux distro. We guess Michael just wanted the case to match the content, hey?

Check out Michael’s YouTube channel for more inexplicably cool builds, such as a one billion volt Thor hammer.

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Global sunrise/sunset Raspberry Pi art installation

24h Sunrise/Sunset is a digital art installation that displays a live sunset and sunrise happening somewhere in the world with the use of CCTV.

Image by fotoswiss.com

Artist Dries Depoorter wanted to prove that “CCTV cameras can show something beautiful”, and turned to Raspberry Pi to power this global project.

Image by fotoswiss.com

Harnessing CCTV

The arresting visuals are beamed to viewers using two Raspberry Pi 3B+ computers and an Arduino Nano Every that stream internet protocol (IP) cameras with the use of command line media player OMXPlayer.

Dual Raspberry Pi power

The two Raspberry Pis communicate with each other using the MQTT protocol — a standard messaging protocol for the Internet of Things (IoT) that’s ideal for connecting remote devices with a small code footprint and minimal network bandwidth.

One of the Raspberry Pis checks at which location in the world a sunrise or sunset is happening and streams the closest CCTV camera.

The insides of the sleek display screen…

Beam me out, Scotty

The big screens are connected with the I2C protocol to the Arduino, and the Arduino is connected serial with the second Raspberry Pi. Dries also made a custom printed circuit board (PCB) so the build looks cleaner.

All that hardware is powered by an industrial power supply, just because Dries liked the style of it.

Software

Everything is written in Python 3, and Dries harnessed the Python 3 libraries BeautifulSoup, Sun, Geopy, and Pytz to calculate sunrise and sunset times at specific locations. Google Firebase databases in the cloud help with admin by way of saving timestamps and the IP addresses of the cameras.

Hardware

The artist stood infront of the two large display screens
Image of the artist with his work by fotoswiss.com

And, lastly, Dries requested a shoutout for his favourite local Raspberry Pi shop Gotron in Ghent.

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