Repairing a vintage 40-kilovolt xenon lamp igniter

Ken Shirriff writes:

What do xenon lamps and the invention of radio have in common? The box below is a 1960s German high voltage unit that CuriousMarc obtained as part of an auction. After some research, we determined that it is an Osram1 igniter2, which generates a 40-kilovolt pulse3 to ignite a xenon arc lamp. The unit didn’t work, so I opened it up, figured out its circuitry, and fixed it, so we could generate some sparks. The circuit turned out to be very similar to a Tesla coil, although the sparks are much smaller.

See the full post on Ken’s blog.

Check out the video after the break.

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DIY voltage and current reference

Petteri Aimonen designed and built his own voltage and current reference:

When developing a data acquisition system, I ran into a need of having fairly accurate current reference to compare against, 0.1% accuracy or better. This is not a particularly high standard, but unable to find a suitable device in my price range, I chose to design my own.

Project info at essentialscrap.com.

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Instaclock | The Magpi 92

Designed to celebrate a new home, Instaclock uses two Raspberry Pi computers to great visual effect. Rosie Hattersley introduces maker Riccardo Cereser’s eyecatching build in issue #92 of The MagPi, out now.

There is nothing like a deadline to focus the mind! Copenhagen-based illustrator and UX designer Riccardo Cereser was about to move into a new apartment with his girlfriend, and was determined his new home would have a unique timepiece. Instaclock is the result.

Having studied at the Copenhagen Institute of Interactive Design, Italian-born Riccardo was keen that his new apartment would include an object that reflected his skills. He began sketching out ideas in Photoshop, starting with the idea of images representing numbers. “A hand showing fingers; a bicycle wheel resembling the number 0; candles on a cake; or the countdown numbers that appear in the beginning of a recording…” he suggests.

Having decided the idea could be used for an interactive clock, he quickly worked out how such an image-based concept might work displaying the hour, minutes, and seconds on displays in three wooden boxes.

Next, he set off around Copenhagen. “I started taking photos of anything that could resemble a number, aiming to create sets of ten pictures each based on a specific theme,” he recalls. “I then thought how awesome it would be to be able to switch the theme and create new sets on the go, potentially by using Instagram.”

This, Riccardo explains, is how the project became known as Instaclock. He was able to visualise his plan using Photoshop and made a prototype for his idea. It was clear that there was no need to display seconds, for example. Minute-by-minute updates would be fine.

Getting animated

Next up was figuring out how to call up and refresh the images displayed. Riccardo had some experience of using Raspberry Pi, and had even made a RetroPie games console. He also had a friend on the interactive design course who might just be able to help

Creative coder Andreas Refsgaard soon got involved, and was quickly able to come up with a Processing sketch for Instaclock.

Having spent dozens of hours looking into how an API might be used to pull in specific images for his clock, Riccardo was grateful that Andreas immediately grasped how it could be done. Riccardo then set parameters in cron for each Raspberry Pi used, so the Instaclock loaded images at startup and moved on to the next image set every ten seconds.

Because Riccardo wanted Instaclock to be as user-friendly as possible, they also added a rule that shuts a screen down if the button on top of it is pressed for ten seconds or more. The script was one he got from The MagPi.

Assembly time

One of the most fun aspects of this project was the opportunity to photograph, draw, or source online images that represent numerals. It was also the most time-consuming, of course. Images reside in Dropbox folders, so can be accessed from anywhere. Deciding on a suitable set of screens to display them, and boxes or frames for them, could also have dragged on but for an impromptu visit to Ikea. Riccardo fortuitously found that the Waveshare screens he selected would fit neatly into the store’s Dragan file organiser boxes. He was then able to laser-cut protective overlays secured with tiny magnets.

Read The MagPi for free!

Find more fantastic projects, tutorials, and reviews in The MagPi #92, out now! You can get The MagPi #92 online at our store, or in print from all good newsagents and supermarkets. You can also access The MagPi magazine via our Android and iOS apps.

Don’t forget our super subscription offers, which include a free gift of a Raspberry Pi Zero W when you subscribe for twelve months.

And, as with all our Raspberry Pi Press publications, you can download the free PDF from our website.

The post Instaclock | The Magpi 92 appeared first on Raspberry Pi.

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How the Raspberry Pi Foundation is responding to the novel coronavirus (part 2)

It’s been a couple of weeks since I posted a blog about how the Raspberry Pi Foundation was responding to the novel coronavirus, and I thought it would be useful to share an update. Writing this has helped me reflect on just how much has changed in such a short space of time.

Getting used to life in the lockdown

Like most of the world, we’ve been getting used to life in the lockdown. As an organisation, we’re very lucky that the vast majority of our work can be done remotely. We’ve moved all of our meetings and lots of events online. Yesterday, we held the first-ever Cambridge Computing Education Research Symposium as an online event, bringing together 250 researchers and practitioners to learn from each other.

Many of us have been figuring out how to combine working at home with additional daily caring responsibilities and homeschooling. Honestly, it’s a work in progress (in my house at least). We’ve introduced new flexible working policies, we’re working doubly hard to stay connected to each other, and we’re introducing initiatives to support well-being.

I am so grateful and frankly proud of the way that the Raspberry Pi team and all of our partners have responded to the crisis: taking care of each other, supporting the community, and focusing on how we can make the biggest positive contribution and impact.

Our mission has never been more vital

Our educational mission has never been more vital. Right now, over 1.5 billion young people aren’t able to access learning through schools or clubs due to the restrictions needed to stop the spread of the virus. Teachers and parents are doing their best to provide meaningful learning experiences at home and online. We have a responsibility and the ability to help.

We are taking four immediate actions to help millions of young people to learn at home during the crisis:

  1. Delivering direct-to-student learning experiences
  2. Supporting teachers to deliver remote lessons
  3. Helping volunteers run virtual and online coding clubs
  4. Getting computers into the hands of children who don’t have one at home

Digital Making at Home

Based on feedback from the community, we’ve launched a series of direct-to-student virtual and online learning experiences called Digital Making at Home. The idea is to inspire and support young people aged 7–17 who are learning at home, independently or with their parents, carers, or siblings. Taking our amazing library of free project resources (which are translated into up to 29 languages) as the starting point, we’re producing instructional videos that support different levels of skills. Each week we’re setting a theme that will inspire and engage young people to learn how to solve problems and express themselves creatively with technology.

Please check it out and let us have your feedback. We’ve got loads of ideas, but we really want to respond to what you need, so let us know.

Supporting teachers to deliver remote lessons

We are working with partners in England (initially) to support teachers to deliver remote lessons on Computing and Computer Science. This work is part of the National Centre for Computing Education. We are adapting the teaching resources that we have developed so that they can be used by teachers who are delivering lessons and setting work remotely. We are designing a programme of online events to support learners using the Isaac Computer Science platform for post-16 students of Computer Science, including small-group mentoring support for both students and teachers.

All of our teaching and learning resources are available for free for anyone to use anywhere in the world. We are interested in working with partners outside England to find additional ways to make them as useful as possible to the widest possible audience.

Helping volunteers run virtual and online coding clubs

We support the world’s largest network of free coding clubs, with over 10,000 Code Clubs and CoderDojos reaching more than 250,000 young people on a regular basis. We are supporting the clubs that are unable to meet in person during the pandemic to move to virtual and online approaches, and we’ve been blown away by the sheer number of volunteers who want to keep their clubs meeting despite the lockdown.

We’re providing training and support to CoderDojo champions, Code Club organisers, educators, and volunteers, including providing free resources, support with handling issues such as safeguarding, and effective design and delivery of online learning experiences. We are also working with our network of 40 international partners to help them support the clubs in their regions.

Access to hardware

We know that a significant proportion of young people don’t have access to a computer for learning at home, and we’re working with incredibly generous donors and fantastic partners in the UK to get Raspberry Pi Desktop Kits distributed for free to children who need them. We’re also in discussions about extending the programme outside the UK.

Get involved

Everything we do is made possible thanks to an incredible network of partners and supporters. We have been overwhelmed (in a good way) by offers of help since the coronavirus pandemic took hold. Here are some of the ways that you can get involved right now:

  • Share what we’re doing. We need as many people as possible to know that we are offering free, meaningful learning experiences for millions of young people. Please help us spread the word. Why not start by sharing this blog with your networks or inside your company?
  • Share your expertise and time. We regularly mobilise tens of thousands of volunteers all over the world to run computing clubs and other activities for young people. We are supporting clubs to continue to run virtually and online. We also need more help with translation of our learning resources. If you have expertise and time to share, get in touch at supporters@raspberrypi.org.
  • Support us with funding. Now more than ever, we need financial support to enable us to continue to deliver meaningful educational experiences for millions of young people at home. You can donate to support our work here.

Stay safe and take care of each other

Wherever you are in the world, I hope that you and yours are safe and well. Please follow the local public health guidance. Stay safe and take care of each other.

Philip Colligan

CEO Raspberry Pi Foundation

The post How the Raspberry Pi Foundation is responding to the novel coronavirus (part 2) appeared first on Raspberry Pi.

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El Carrillon | The MagPi 92

Most Raspberry Pi projects we feature debut privately and with little fanfare – at least until they’re shared by us.

The El Carrillon project, however, could hardly have made a more public entrance. In September 2019 it was a focal point of Argentina’s 49th annual Fiesta Nacional de la Flor (National Flower Festival), where its newly overhauled bell tower proudly rang out a brand-new, Raspberry Pi-enabled tune.

Many years ago, festival organisers created custom hardware with a PIC (programmable interface) microcontroller to control 18 tuned bells. Each bell is associated with a musical note, from A3 to D5 with all the semitones. Until its long overdue update, the tower’s 18 bells had rung the tune to Ayer, also known as Yesterday by The Beatles. They now have a brand-new repertoire of MIDI-based tunes, including the theme from Star Wars.

For Gerardo Richarte, the originator of the project, there was a little extra pressure: his dad is on the board of the NGO that organises Fiesta Nacional de la Flor, and challenged his son to come up with a way to update the bells so different songs could be played.

Ringing the changes

With the challenge accepted, Mariano Martinez Peck explains, “We chose Raspberry Pi because it was inexpensive, yet powerful enough to run Linux, Python, and VA Smalltalk. We could find ready-made HATs that actually matched the pinout of the existing flat cables without much hacking, and only a minimal amount of other hardware was needed. In addition, there was plenty of documentation, materials, tutorials, and GPIO libraries available.”

The bells had a pre-existing driver module

The project aim was to be able to run a mobile-friendly website within Raspberry Pi Zero that allowed control, configuration, and playback of MIDI songs on the bell tower. “In addition, we wanted to allow live playing from a MIDI keyboard,” says Mariano. The project developed as a live test and iteration update, but the final build only came together when Mariano and Gerardo’s moment in the spotlight arrived and El Carrillon rang out the first new tunes.

Coding a classic

The decades-old chimes were controlled by assembly code. This was superseded by Python when the team made the switch to Raspberry Pi Zero. Mariano explains, “Raspberry Pi allowed us to use Python to directly interface with both the old and new hardware and get the initial project working.”

However, the Python code was itself replaced by object-oriented VA Smalltalk code – an environment both Mariano and Gerardo are adept at using. Mariano says, “Smalltalk’s live programming environment works really well for fast, iterative development and makes software updates quick and easy without the need for recompilation that lower-level languages [such as assembly or C/C++] would need.”

El Carrillon’s bells can now play any MIDI file on Raspberry Pi, and the notes of the song will be mapped to the tuned bells. However, as the testing process revealed, some songs are more recognisable than others when reproduced on chimes.

A final feature enabled Gerardo to bag some brownie points with his father-in-law. He recently added a web interface for controlling, configuring, and playing songs, meaning the bells can now be controlled remotely and the song selected via a smartphone app.

The El Carrillon bell tower forms a striking backdrop to the flower festival and other cultural events

Read The MagPi for free!

Find more amazing projects and tutorials in The MagPi #92, out now! You can get The MagPi #92 online at our store, or in print from all good newsagents and supermarkets. You can also access The MagPi magazine via our Android and iOS apps.

Don’t forget our fantastic subscription offers, which include a free gift of a Raspberry Pi Zero W when you subscribe for twelve months.

And, as with all our Raspberry Pi Press publications, you can download the free PDF from our website.

The post El Carrillon | The MagPi 92 appeared first on Raspberry Pi.

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#FreePCB via Twitter to 2 random RTs

Every Tuesday we give away two coupons for the free PCB drawer via Twitter. This post was announced on Twitter, and in 24 hours we’ll send coupon codes to two random retweeters. Don’t forget there’s free PCBs three times a every week:

  • Hate Twitter and Facebook? Free PCB Sunday is the classic PCB giveaway. Catch it every Sunday, right here on the blog
  • Tweet-a-PCB Tuesday. Follow us and get boards in 144 characters or less
  • Facebook PCB Friday. Free PCBs will be your friend for the weekend

Some stuff:

  • Yes, we’ll mail it anywhere in the world!
  • Check out how we mail PCBs worldwide video.
  • We’ll contact you via Twitter with a coupon code for the PCB drawer.
  • Limit one PCB per address per month please.
  • Like everything else on this site, PCBs are offered without warranty.

We try to stagger free PCB posts so every time zone has a chance to participate, but the best way to see it first is to subscribe to the RSS feed, follow us on Twitter, or like us on Facebook.

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5 ways to live (and thrive) while social distancing

The novel coronavirus has dramatically changed how we spend time and share physical and virtual space with each other. On Friday, March 27, conflict mediator and author Priya Parker joined head of TED Chris Anderson and current affairs curator Whitney Pennington Rodgers on TED Connects to discuss what we all can do to stay connected and sustain relationships while apart during the pandemic. Here’s some advice to help you get through this uncertain time:

Bring intention to planning a virtual gathering

As platforms like Zoom, Slack and email become more integrated into our lives, it’s clear that technology will play an important tool in helping us keep in touch. Whether you’re organizing a Zoom dinner party or Facetiming a friend, Parker invites us to consider how we can elevate the conversation beyond just check-ins. In planning a virtual gathering, ask:

  • Who’s joining and why?
  • What are your community’s needs?
  • What’s the reason you’re coming together?

As the pandemic evolves, these needs will likely shift. Stay attuned to the kinds of connections your communities are seeking.

Include fun themes to elevate your digital get-togethers

Parker suggests centering your gatherings around themes or activities to encourage more meaningful and purposeful conversations. Incorporate elements of the physical world to create a shared experience, like asking everyone to wear a funny costume or making the same recipe together. Though screens don’t quite replace the energy of in-person gatherings, we can still strengthen community bonds by reminding ourselves that there are real people on the other end of our devices.

Set healthy boundaries to maintain wellbeing

As we’re figuring out the best way to exist in the digital world, it’s also crucial we put in the effort to meaningfully connect with those we’re quarantining with. The distinctions between time to work, socialize and rest can grow blurrier by the day, so be sure to set boundaries and ground rules with those you live with. In having this conversation with your roommates, family or partner, reflect on these prompts:

  • How do you want to distinguish time spent together versus apart?
  • How do you want to share time together?
  • Since we look at screens most of the day, could it be helpful to set no-screen times or brainstorm new, non-digital ways to hang out?

Allow yourself to reflect on the unknown

It’s important to acknowledge that this is not a normal time, Parker says. The coronavirus pandemic has transformed the world, and as a global society we’ll experience the reverberations of this period as they ripple across every sector of human life. Make sure to create space for those conversations, too.

Take time to wander through the unknown, to talk about how we are being changed — individually and collectively — by this shared experience. It’s perfectly normal to feel worried, vulnerable, even existential, and this may be a great time to lean into those feelings and think about what really matters to you.

Recognize the power and feeling community brings — no matter the size

While the coronavirus pandemic has physically isolated many of us from each other, our ingenuity and resilience ensures that we can still build and forge community together. Across the world, people are gathering in new and amazing ways to set up “care-mongering” support groups, sing with their neighbors, take ceramics classes, knit together and break bread.

Now is the time to discover (or rediscover) the value and power of community. We are all members of many different communities: our neighborhoods, families, countries, faith circles and so on. Though we’re living in unprecedented times of social isolation, we can forge stronger bonds by gathering in ways that reflect our best values and principles. In the United Kingdom, a recent campaign asked people across the country to go outside at a synchronized time and collectively applaud health workers on the frontlines of the crisis; a similar effort was made across India to ring bells in honor of the ill and those caring for them. During this crisis and beyond, we can use thoughtful ritual-making to transform our unease and isolation into community bonding.

“Gathering is contagious,” Parker says. “These small, simple ideas allow people to feel like we can shape some amount — even a small amount — of our collective reality together.”

Looking for more tips, advice and wisdom? Watch the full conversation with Priya below (and join us for TED Connects, weekdays at 12pm ET):

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Code Hyper Sports’ shooting minigame | Wireframe #35

Gun down the clay pigeons in our re-creation of a classic minigame from Konami’s Hyper Sports. Take it away, Mark Vanstone

Hyper Sports

Hyper Sports’ Japanese release was tied in with the 1984 Summer Olympics.

Hyper Sports

Konami’s sequel to its 1983 arcade hit, Track & Field, Hyper Sports offered seven games – or events – in which up to four players could participate. Skeet shooting was perhaps the most memorable game in the collection, and required just two buttons: fire left and fire right.

The display showed two target sights, and each moved up and down to come into line with the next clay disc’s trajectory. When the disc was inside the red target square, the player pressed the fire button, and if their timing was correct, the clay disc exploded. Points were awarded for being on target, and every now and then, a parrot flew across the screen, which could be gunned down for a bonus.

Making our game

To make a skeet shooting game with Pygame Zero, we need a few graphical elements. First, a static background of hills and grass, with two clay disc throwers each side of the screen, and a semicircle where our shooter stands – this can be displayed first, every time our draw() function is called.

We can then draw our shooter (created as an Actor) in the centre near the bottom of the screen. The shooter has three images: one central while no keys are pressed, and two for the directions left and right when the player presses the left or right keys. We also need to have two square target sights to the left and right above the shooter, which we can create as Actors.

When the clay targets appear, the player uses the left and right buttons to shoot either the left or right target respectively.

To make the clay targets, we create an array to hold disc Actor objects. In our update() function we can trigger the creation of a new disc based on a random number, and once created, start an animation to move it across the screen in front of the shooter. We can add a shadow to the discs by tracking a path diagonally across the screen so that the shadow appears at the correct Y coordinate regardless of the disc’s height – this is a simple way of giving our game the illusion of depth. While we’re in the update() function, looping around our disc object list, we can calculate the distance of the disc to the nearest target sight frame, and from that, work out which is the closest.

When we’ve calculated which disc is closest to the right-hand sight, we want to move the sight towards the disc so that their paths intersect. All we need to do is take the difference of the Y coordinates, divide by two, and apply that offset to the target sight. We also do the same for the left-hand sight. If the correct key (left or right arrows) is pressed at the moment a disc crosses the path of the sight frame, we register a hit and cycle the disc through a sequence of exploding frames. We can keep a score and display this with an overlay graphic so that the player knows how well they’ve done.

And that’s it! You may want to add multiple players and perhaps a parrot bonus, but we’ll leave that up to you.

Here’s Mark’s code snippet, which creates a simple shooting game in Python. To get it working on your system, you’ll need to install Pygame Zero. And to download the full code and assets, go here.

Get your copy of Wireframe issue 35

You can read more features like this one in Wireframe issue 35, available now at Tesco, WHSmith, and all good independent UK newsagents.

Or you can buy Wireframe directly from Raspberry Pi Press — delivery is available worldwide. And if you’d like a handy digital version of the magazine, you can also download issue 35 for free in PDF format.

Make sure to follow Wireframe on Twitter and Facebook for updates and exclusive offers and giveaways. Subscribe on the Wireframe website to save up to 49% compared to newsstand pricing!

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