App note: Automobile harness protection

Polyswitch fuse use in automobile, app note from Littelfuse. Link here (PDF)

A vehicle’s ideal harness scheme has a hierarchal, tree-like structure with main power “trunks” dividing into smaller “branches,” with overcurrent protection at each node. This architecture allows the use of smaller, space-saving wires that can reduce weight and cost. It also optimizes system protection while providing fault isolation, which ultimately improves reliability.

Using resettable circuit protection devices that do not need to be driver accessible offers designers a number of solutions that may be used separately or in combination. A single junction box located in the instrument panel may still be employed. However, rather than being positioned close to the conventional fuses, resettable PolySwitch devices can be located inside the box or on another face, which can save frontal area. Moreover, placing them closer to the connectors allows the trace’s length to be reduced. As a result, the overall junction box can be downsized.

from Dangerous Prototypes

App note: Automatic AC line voltage selector

Implementation of automatic AC line voltage selector, App note from Littelfuse. Link here (PDF)

In some cases, appliances and equipment are able to operate when supplies by two different levels of AC line voltage to their main terminals (10V or 240V). This is why, it is very common that appliances and equipment have mechanical selectors or switches as an option for selecting the level of voltage needed. Nevertheless, it is also very common that these types of equipment can suffer extensive damage caused for not putting the selector in the right position. To prevent these kind of problems, thyristors can be used as a solution for making automatic voltage selectors in order to avoid possibilities of equipment damage due to over or low voltages AC line supplies to them.

from Dangerous Prototypes

Let’s make art at home this week

Digital Making at Home: Make art

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Digital Making at Home is a program which encourages young people to code and share along with us, featuring weekly themed content, code-along videos, livestreams, and more!

This week, we’re exploring making art with code. Many young makers are no stranger to making art, especially the digital kind! This week we’re inviting them to bring their most colourful and imaginative ideas to life with code.

So this week for Digital Making at Home, let’s make some art!

The post Let’s make art at home this week appeared first on Raspberry Pi.

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Values reset: The talks of TED2020 Session 2

There’s a theory that the shock we’re currently experiencing is intense enough to force a radical reset of our values — of how we are and how we act. In an idea-packed session 2 of TED2020, speakers from across disciplines and walks of life looked to this aspiration of a “values reset,” sharing new thinking on topics ranging from corporate responsibility down to our individual responsibilities and the things each of us can right now. Below, a recap of the night’s inspiring talks and performances.

“Nobody works in a vacuum. The men and women who run companies actively cocreate the reality we all have to share. And just like with global warming, we are each of us responsible for the collective consequences of our individual decisions and actions,” says filmmaker and activist Abigail Disney. She speaks at TED2020: Uncharted on May 28, 2020. (Photo courtesy of TED)

Abigail Disney, Filmmaker, activist

Big idea: Respect, dignity and a guaranteed livable wage are the right of all workers, not the privilege of a select few.

How? As CEO of the Disney Company, Roy Disney believed he had a moral obligation to every person who worked at the company. Though her grandfather wasn’t perfect, Abigail Disney says he believed that workers were worthy of immense respect — and he put that belief into practice by creating jobs with fair wages and benefits. In honor of her grandfather’s legacy, Disney advocates for income equality for all workers — and calls out the company that bears her name, asking them to do better for their workers. Our conscience and empathy should drive us, she says, not profits or economic growth. Disney believes we need a system-wide shift, one that recognizes that all workers deserve the wages, protections and benefits that would enable them to live full, secure and dignified lives.

Quote of the talk: “Nobody works in a vacuum. The men and women who run companies actively cocreate the reality we all have to share. And just like with global warming, we are each of us responsible for the collective consequences of our individual decisions and actions.”

Back by brilliant illustrations from Laolu Senbanjo, journalist and satirist Adeola Fayehun shares her work exposing corruption in Africa with sharp, incisive humor. She speaks at TED2020: Uncharted on May 28, 2020. (Photo courtesy of TED)

Adeola Fayehun, Journalist, satirist

Big idea: Africa is overflowing with all the natural resources, intellectual skill and talent it needs. To flourish, its people need to hold corrupt leaders accountable.

Why? On her show Keeping It Real With Adeola, Adeola Fayehun exposes corruption in Africa with sharp, incisive humor. She urges those outside Africa to stop seeing the continent through the lens of their preconceived notions, and encourages us all to call out false policies and shatter stereotypes. “Please listen more,” she says. “Listen to your African friends without a preconceived notion of what you think they’re going to say. Read African books, watch African movies, visit Africa or, at the very least, learn some of the names of our 54 beautiful countries.”

Quote of the talk: “Africa is like a sleeping giant. The truth is I am trying to wake up this giant. That’s why I air the dirty laundry of those in charge of the giant.”

Rufus Wainwright performs “Peaceful Afternoon” and “Going To A Town” at TED2020: Uncharted on May 28, 2020. (Photo courtesy of TED)

From his home in Los Angeles, songwriter Rufus Wainwright shares intimate versions of his songs “Peaceful Afternoon” and “Going To A Town.” Gorgeous slow pans are courtesy of Jörn Weisbrodt, Wainwright’s husband and videographer for the performances.

“We hate the idea that really important things in life might happen by luck or by chance, that really important things in our life are not under our control,” says psychology professor Barry Schwartz. He speaks at TED2020: Uncharted on May 28, 2020. (Photo courtesy of TED)

Barry Schwartz, Psychology professor

Big idea: Our society is predicated on the idea that the distribution of opportunity is fair — but, in reality, working hard and playing by the rules is no guarantee of success. Good fortune and luck have far more to do with our opportunities (and therefore our future success) than we’re willing to admit.

How? Just look at the ultra-competitive landscape of college admissions, where a dearth of slots for qualified and capable students has created an epidemic of anxiety and depression among teenage university applicants long before they even make it to the job market. Schwartz suggests that the belief that working hard automatically leads to success blinds us to a core injustice: many of us simply will not get what we want. If our educational institutions — and our nation’s employers — were to emphasize this injustice by picking their students and employees randomly from a pool of those most likely to succeed, we might be forced to recognize the role that fortune plays in our lives.

Quote of the talk: “We hate the idea that really important things in life might happen by luck or by chance, that really important things in our life are not under our control.”

“I have a choice, right now, in the midst of the storm, to decide to overcome,” says Seattle Seahawks quarterback Russel Wilson. He speaks at TED2020: Uncharted on May 28, 2020. (Photo courtesy of TED)

Russell Wilson, Seattle Seahawks quarterback

Big idea: “Neutral thinking” can transform your life and help you unlock sustained personal success.

How? Athletes train their bodies to run faster, jump higher, achieve more — so why don’t they train their minds, too? For the past 10 years, Wilson has been doing just that with the assistance of mental conditioning coach Trevor Moawad. By harnessing the technique of “neutral thinking” — a strategy that emphasizes judgment-free acceptance of the present moment — Wilson has been able to maintain focus in high-pressure situations. Positivity can be dangerous and distracting, Wilson says, and negativity is sure to bring you down — but by honing a neutral mental game and executing in the present moment, you set yourself up to succeed.

Quote of the talk:I have a choice, right now, in the midst of the storm, to decide to overcome.”

from TED Blog

Latest Raspberry Pi OS update – May 2020

Along with yesterday’s launch of the new 8GB Raspberry Pi 4, we launched a beta 64-bit ARM version of Debian with the Raspberry Pi Desktop, so you could use all those extra gigabytes. We also updated the 32-bit version of Raspberry Pi OS (the new name for Raspbian), so here’s a quick run-through of what has changed.

NEW Raspberry Pi OS update (May 2020)

An update to the Raspberry Pi Desktop for all our operating system images is also out today, and we’ll have more on that in tomorrow’s blog post. For now, fi…


As many of you know, we have our own publishing company, Raspberry Pi Press, who publish a variety of magazines each month, including The MagPi, HackSpace magazine, and Wireframe. They also publish a wide range of other books and magazines, which are released either to purchase as a physical product (from their website) or as free PDF downloads.

To make all this content more visible and easy to access, we’ve added a new Bookshelf application – you’ll find it in the Help section of the main menu.

Bookshelf shows the entire current catalogue of free magazines – The MagPi, HackSpace magazine and Wireframe, all with a complete set of back issues – and also all the free books from Raspberry Pi Press. When you run the application, it automatically updates the catalogue and shows any new titles which have been released since you last ran it with a little “new” flash in the corner of the cover.

To read any title, just double-click on it – if it is already on your Raspberry Pi, it will open in Chromium (which, it turns out, is quite a good PDF viewer); if it isn’t, it will download and then open automatically when the download completes. You can see at a glance which titles are downloaded and which are not by the “cloud” icon on the cover of any file which has not been downloaded.

All the PDF files you download are saved in the “Bookshelf” directory in your home directory, so you can also access the files directly from there.

There’s a lot of excellent content produced by Raspberry Pi Press – we hope this makes it easier to find and read.


As mentioned in my last blog post (here), one of the areas we are currently trying to improve is accessibility to the Desktop for people with visual impairments. We’ve already added the Orca screen reader (which has had a few bug fixes since the last release which should make it work more reliably in this image), and the second recommendation we had from AbilityNet was to add a screen magnifier.

This proved to be harder than it should have been! I tried a lot of the existing screen magnifier programs that were available for Debian desktops, but none of them really worked that well; I couldn’t find one that worked the way the magnifiers in the likes of MacOS and Ubuntu did, so I ended up writing one (almost) from scratch.

To install it, launch Recommended Applications in the new image and select Magnifier under Universal Access. Once it has installed, reboot.

You’ll see a magnifying glass icon at the right-hand end of the taskbar – to enable the magnifier, click this icon, or use the keyboard shortcut Ctrl-Alt-M. (To turn the magnifier off, just click the icon again or use the same keyboard shortcut.)

Right-clicking the magnifier icon brings up the magnifier options. You can choose a circular or rectangular window of whatever size you want, and choose by how much you want to zoom the image. The magnifier window can either follow the mouse pointer, or be a static window on the screen. (To move the static window, just drag it with the mouse.)

Also, in some applications, you can have the magnifier automatically follow the text cursor, or the button focus. Unfortunately, this depends on the application supporting the required accessibility toolkit, which not all applications do, but it works reasonably well in most included applications. One notable exception is Chromium, which is adding accessibility toolkit support in a future release; for now, if you want a web browser which supports the accessibility features, we recommend Firefox, which can be installed by entering the following into a terminal window:

sudo apt install firefox-esr

(Please note that we do not recommend using Firefox on Raspberry Pi OS unless you need accessibility features, as, unlike Chromium, it is not able to use the Raspberry Pi’s hardware to accelerate video playback.)

I don’t have a visual impairment, but I find the magnifier pretty useful in general for looking at the finer details of icons and the like, so I recommend installing it and having a go yourself.

User research

We already know a lot of the things that people are using Raspberry Pi for, but we’ve recently been wondering if we’re missing anything… So we’re now including a short optional questionnaire to ask you, the users, for feedback on what you are doing with your Raspberry Pi in order to make sure we are providing the right support for what people are actually doing.

This questionnaire will automatically be shown the first time you launch the Chromium browser on a new image. There are only four questions, so it won’t take long to complete, and the results are sent to a Google Form which collates the results.

You’ll notice at the bottom of the questionnaire there is a field which is automatically filled in with a long string of letters and numbers. This is a serial number which is generated from the hardware in your particular Raspberry Pi which means we can filter out multiple responses from the same device (if you install a new image at some point in future, for example). It does not allow us to identify anything about you or your Raspberry Pi, but if you are concerned, you can delete the string before submitting the form.

As above, this questionnaire is entirely optional – if you don’t want to fill it in, just close Chromium and re-open it and you won’t see it again – but it would be very helpful for future product development if we can get this information, so we’d really appreciate it if as many people as possible would fill it in.

Other changes

There is also the usual set of bug fixes and small tweaks included in the image, full details of which can be found in the release notes on the download page.

One particular change which it is worth pointing out is that we have made a small change to audio. Raspberry Pi OS uses what is known as ALSA (Advanced Linux Sound Architecture) to control audio devices. Up until now, both the internal audio outputs on Raspberry Pi – the HDMI socket and the headphone jack – have been treated as a single ALSA device, with a Raspberry Pi-specific command used to choose which is active. Going forward, we are treating each output as a separate ALSA device; this makes managing audio from the two HDMI sockets on Raspberry Pi 4 easier and should be more compatible with third-party software. What this means is that after installing the updated image, you may need to use the audio output selector (right-click the volume icon on the taskbar) to re-select your audio output. (There is a known issue with Sonic Pi, which will only use the HDMI output however the selector is set – we’re looking at getting this fixed in a future release.)

Some people have asked how they can switch the audio output from the command line without using the desktop. To do this, you will need to create a file called .asoundrc in your home directory; ALSA looks for this file to determine which audio device it should use by default. If the file does not exist, ALSA uses “card 0” – which is HDMI – as the output device. If you want to set the headphone jack as the default output, create the .asoundrc file with the following contents:

defaults.pcm.card 1
defaults.ctl.card 1

This tells ALSA that “card 1” – the headphone jack – is the default device. To switch back to the HDMI output, either change the ‘1’s in the file to ‘0’s, or just delete the file.

How do I get it?

The new image is available for download from the usual place: our Downloads page.

To update an existing image, use the usual terminal command:

sudo apt update
sudo apt full-upgrade

To just install the bookshelf app:

sudo apt update
sudo apt install rp-bookshelf

To just install the magnifier, either find it under Universal Access in Recommended Software, or:

sudo apt update
sudo apt install mage

You’ll need to add the magnifier plugin to the taskbar after installing the program itself. Once you’ve installed the program and rebooted, right-click the taskbar and choose Add/Remove Panel Items; click Add, and select the Magnifier option.

We hope you like the changes — as ever, all feedback is welcome, so please leave a comment below!

The post Latest Raspberry Pi OS update – May 2020 appeared first on Raspberry Pi.

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8GB Raspberry Pi 4 on sale now at $75

The long-rumoured 8GB Raspberry Pi 4 is now available, priced at just $75.

Raspberry Pi 4 is almost a year old, and it’s been a busy year. We’ve sold nearly 3 million units, shipped a couple of minor board revisions, and reduced the price of the 2GB variant from $45 to $35. On the software side, we’ve done enormous amounts of work to reduce the idle and loaded power consumption of the device, passed OpenGL ES 3.1 conformance, started work on a Vulkan driver, and shipped PXE network boot mode and a prototype of USB mass storage boot mode – all this alongside the usual round of bug fixes, feature additions, and kernel version bumps.

While we launched with 1GB, 2GB and 4GB variants, even at that point we had our eye on the possibility of an 8GB Raspberry Pi 4. We were so enthusiastic about the idea that the non-existent product made its way into both the Beginner’s Guide and the compliance leaflet.


The BCM2711 chip that we use on Raspberry Pi 4 can address up to 16GB of LPDDR4 SDRAM, so the real barrier to our offering a larger-memory variant was the lack of an 8GB LPDDR4 package. These didn’t exist (at least in a form that we could address) in 2019, but happily our partners at Micron stepped up earlier this year with a suitable part. And so, today, we’re delighted to announce the immediate availability of the 8GB Raspberry Pi 4, priced at just $75.

Multum in parvo

It’s worth reflecting for a moment on what a vast quantity of memory 8GB really is. To put it in retro-perspective (retrospective?), this is a BBC Micro‘s worth of memory for every bit in the memory of the BBC Micro; it’s a little over 13,000 times the 640KB that Bill Gates supposedly thought should be enough for anyone (sadly, it looks as though this quote is apocryphal).

If you’re a power user, intending to compile and link large pieces of software or run heavy server workloads, or you simply want to be able to have even more browser tabs open at once, this is definitely the Raspberry Pi for you.

What else has changed?

To supply the slightly higher peak currents required by the new memory package, James has shuffled the power supply components on the board, removing a switch-mode power supply from the right-hand side of the board next to the USB 2.0 sockets and adding a new switcher next to the USB-C power connnector. While this was a necessary change, it ended up costing us a three-month slip, as COVID-19 disrupted the supply of inductors from the Far East.

New switcher, new inductors, new schedule

Other than that, this is the same Raspberry Pi 4 you’ve come to know and love.

What about 64-bit?

Our default operating system image uses a 32-bit LPAE kernel and a 32-bit userland. This allows multiple processes to share all 8GB of memory, subject to the restriction that no single process can use more than 3GB. For most users this isn’t a serious restriction, particularly since every tab in Chromium gets its own process. Sticking with a 32-bit userland has the benefit that the same image will run on every board from a 2011-era alpha board to today’s shiny new 8GB product.

But power users, who want to be able to map all 8GB into the address space of a single process, need a 64-bit userland. There are plenty of options already out there, including Ubuntu and Gentoo.

Not to be left out, today we’ve released an early beta of our own 64-bit operating system image. This contains the same set of applications and the same desktop environment that you’ll find in our regular 32-bit image, but built against the Debian arm64 port.

Both our 32-bit and 64-bit operating system images have a new name: Raspberry Pi OS. As our community grows, we want to make sure it’s as easy as possible for new users to find our recommended operating system for Raspberry Pi. We think the new name will help more people feel confident in using our computers and our software. An update to the Raspberry Pi Desktop for all our operating system images is also out today, and we’ll have more on that in tomorrow’s blog post.

You can find a link to the new 64-bit image, and some important caveats, in this forum post.

The post 8GB Raspberry Pi 4 on sale now at $75 appeared first on Raspberry Pi.

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Using modular synth to control Atem camera switching over WiFi using ESP8266

Sebastian writes:

I’ve been wanting to control my camera switching from my modular synth. So I made a setup where a low to high transition on a digital input on an ESP8266 module generates an OSC message on the WiFi network for the ATEM Mini Pro switcher to change cameras. Here, it’s triggered from the kick but it could be any clock, gate or trigger signal. Makes use of atemOSC.

More details on Little-Scale blog.

Check out the video after the break.

from Dangerous Prototypes