liz | Raspberry Pi

Troubleshooting: so easy a ten-year-old can do it

The ten-year-old in question is Jessica, Gordon’s daughter, who dropped into the office last week to give us a hand testing some Raspberry Pis that customers had sent back to the manufacturers as “faulty”. Whenever this happens, the Pis are passed on to us or to the Sony factory in Wales where the Pis are built, and we test them to find out what’s going on and to ensure that there isn’t a bug in manufacturing.

At the moment, we see returns in the order of about 0.02% of all units (the ones Jessica is working on are on the right of her desk). The factory processes are always being refined, and we hope to see this number come down even further as all of our production transitions to the UK. As usually happens when we troubleshoot returns, though, we found that around half of Jessica’s Pis weren’t faulty at all. We can’t emphasise this enough: before you decide you’ve got a broken unit, check out the troubleshooting forum and the wiki. If your Pi doesn’t work, the first check you should make is that the power supply you’re using is a branded, reliable 5v supply. Many no-name supplies (especially in the US, for some reason) do not actually provide the voltage that they claim to, and that’s been causing all kinds of problems.

Jessica finds another working Pi. Later, we’re sending her up that ladder to clean out the asbestos tube.

You should also ensure that you’re running the latest version of Raspbian. (Lorna just mailed me this morning with another handful of emails from a group of people swearing blind their Pis are broken. They weren’t. The people in question were using SD cards with an out-of-date image that they’d bought from a third-party vendor, that didn’t work with the newer chipset on their Raspberry Pis.) If you aren’t sure about your SD card image, see this post from March. Pre-flashed cards from third party dealers on Amazon or eBay are a bit of crapshoot, and they’re something we can’t police; if you need one, get your pre-flashed card from one the companies we licence to sell the Pi itself. (See the top right of the page.) Several of Jessica’s test cases had been sent back to Farnell and RS because of this issue, and while that’s great for Jessica, it’s really frustrating for the customer who ends up without a Pi for a week and who will probably find their next Pi has the same problem, because they’re using the same card. (I am aware of one person who sent SIX Raspberry Pis back to Farnell one after the other, insisting that they were all broken, that we/Farnell were charlatans, etc. etc. In the end it turned out that he hadn’t actually flashed the SD card at all. This is an extreme case.)

We did make sure that Jessica was rewarded for all her hard work: this is what we were doing on Monday.

Thanks Jessica!

Gigapi: a Raspberry Pi rig for gigapixel photography

We’ve seen a number of photographers who have taken to the Pi as a way to bring down the cost of the sort of kit that was, pre-Pi, outside the budgets of mere mortals. Case in point: gigapixel photography. A gigapixel image is made up of (at least) a billion pixels, which means you’ve now got access to the sort of fine and vivid detail on your monitor that we mere humans with our shonky eyeballs could only dream of until recently.

At the moment, a camera that can take a gigapixel image all in one shot is the sort of fantasy hardware that the military is pouring millions into. But if you’re not in charge of a defence silo, you can still take your own gigapixel images by stitching together many megapixel-sized images from an SLR camera on a motorised mount into a giant, seamless mosaic with very fine detail. You’ll need something approaching a defence budget if you’re going to do this yourself without building your own hardware, though; I spent a few seconds googling and found that off-the-shelf motorised rigs for your camera can cost nearly $1000.

Tim and Jack Stocker thought this was daft, so they built their own out of MDF, some Lego turntables, and a Pi with a cheap stepper motor attached.

Gigapi in use. (We love the yellow paint job – it’s a beautifully made piece of kit.) Click to enlarge.

This is the instrument box Tim is holding in the photo above, opened so you can peer inside. Click to enlarge.

The Pi has a lot of computation to do here: Jack’s software (which you can download on GitHub) works out the horizontal and vertical angles required, the camera sensor size, the length of zoom used and the image overlap required to stitch everything together into a tidy mosaic later on. It figures out how many photos are needed to complete the picture, when the stepper motors should be moved, and by how much and in what order; and when and for how long the shutter should be opened – it also deals with the focus.

You’ll find a long description of how to reproduce the Stockers’ setup, with a parts list, enough information for you to make your own shutter control circuit and more at GigaPi.

For obvious reasons, I can’t host a sample gigapixel image here. But you can find some pictures taken with the Stockers’ rig, one of which is a simply ridiculous 15.2 gigapixels (and enormous fun; it’s full of Easter eggs, and the detail’s so good that you can count how many peanuts are left in the bird feeder) at gigapan.com.

Bonus fact of the day: Sophie Wilson, of ARM and BBC Micro fame, is also a gigapixel photographer, and she’s created some really beautiful pictures using the technique – the architectural photos are my favourites. She occasionally gives talks in and around Cambridge on the subject, minus the Raspberry Pi (I spotted an advert for one in my local post office last week). Keep an eye out if you’re in town.

Tokyo: Big Raspberry Jam 2013

Eben and I are going to be out of the UK for much of the rest of May, doing press, meeting partners, visiting Raspberry Pi fans, hanging out with science fair kids and giving talks. We’ll be in Phoenix for Intel ISEF, San Francisco for Maker Faire (come and listen to our talk! We don’t have a stand this year, but Raspberry Pis will be on sale in the Make Shed), and, most excitingly for both of us, in Tokyo for the Japanese Raspberry Pi User Group’s Big Raspberry Jam on May 25.

Masafumi Ohta, who moderates the forums here (he’s most often to be found in the Japanese language forum, but also pops up in the English sections every now and then), is running the event. Admission is free. We’ve heard from people who don’t even live in Japan who are making the trip to Tokyo; it promises to be an amazing day, with lots of hacking sessions, tutorials, talks and opportunities to meet like-minded Pi enthusiasts. We were last in Tokyo back in November; the Pi has become much more easily available in Japan since then, and we’ve even seen an official Japanese translation of the Raspberry Pi User Guide appear since our last visit. Masafumi-san’s been sending me artwork for displays and badges, and notes about the day: we can’t wait to get stuck in. RS Components, who have a large presence in the far east and are one of our two manufacturing distribution partners, will be sponsoring the event.

Eben in Akihabara Electric Town last November.

Masafumi-san has asked me to publish the following information here on the blog. If you’re in Tokyo on the day, please come and see us!

–

Japanese Raspberry Pi Users Group will hold the event to welcome Eben and Liz Upton, Founder of Raspberry Pi Foundation coming to Japan. It is for encouraging Raspberry Pi users and community in Japan, now growing up rapidly.

Gathering 150+ people at the big event – 4 sessions, 1 mini session,3 LTs and more. It is also not only for Raspberry Pi users and geeks, but also the Raspberry Pi beginners. RS Components and some companies help the event, and have booths exhibiting Raspberry Pis and some stuff (books,boards,cases…and more).

13:00-13:30 Door Open
13:30-13:40 Greeting from Japanese Raspberry Pi Users Group and RS Components
13:40-14:30 Keynote by Eben Upton of Raspberry Pi Foundation
14:30-14:40 break
14:40-15:10 Session:WordPress Home Server with Raspberry Pi by Yuriko Ikeda
15:10-15:40 Session:Scratch Hacking with Raspberry Pi by Kazuhiro Abe
15:40-15:50 break
15:50-16:20 Session:Let’s play ‘Eject Command’ with Raspberry Pi – CD-ROM Cooking with Raspberry PI by Akira Ouchi
16:20-16:50 Session:Gadget Colloquia for Unix Natives by Hiroyuki Ohno
16:50-17:00 break
17:00-17:15 Mini Session:Raspberry Pi Lego Cases Cooking by Keika Komura
17:15-17:30 Lightning Talks (5 min x3)
17:00-17:50 Introducing Raspberry Pi by RS Components
17:50-18:00 Closing event
19:00- Raspberry PIe after-party for the attendees

For more information please check Japanese Raspberry Pi Users Group website.

Registration: http://atnd.org/event/E0014486 (for Japanese)

http://bigraspberryjamtokyo2013.eventbrite.com (for Non-Japanese).

Live motion tracking

It is a bank holiday, and we are all quite…cheerful, post company barbecue, so I will keep this brief. Here’s a motion tracking demo from Erik Haberup. He says:

In case the Raspberry Pi team would like another example of the versatility of their product.

This is my capstone project for the University of Nebraska – Lincoln (Computer Electronics Engineering) which uses a Raspberry Pi to wirelessly transmit live motion tracking data from a set of 13 inertial measurement units.

I’ll ask Erik for some more information, but in the meantime, I thought you might like to enjoy this *outstanding* video.

A very happy first birthday to The MagPi!

The MagPi is a free magazine made by Raspberry Pi fans for Raspberry Pi fans. It’s the example of just how remarkable the Raspberry Pi community is that we point to most often: volunteer enthusiasts with no publishing experience have been producing a really tight, entertaining, and educational magazine for twelve months now, and it’s just getting better and better.

The MagPi is a community magazine, which is not produced or otherwise fiddled around with by the Raspberry Pi Foundation. This month’s issue is a little more Foundation-heavy than usual, though, because it’s a celebratory edition: you’ll find an article from me, and (rather more interestingly) a very in-depth interview with Pete Lomas, our Grand Vizier of Hardware.

Most excitingly of all, there’s a birthday competition this month, where you can win £1000 of Pi hardware to play with. You’ll find a really helpful comparison of Raspberry Pi operating systems, a musical tutorial, an exploration of just how the Sweetbox guys went about bringing their case to market, and much more.

I don’t have enough good things to say about the MagPi team, and the crazy amount of work they’ve put in over the last year to help people get to grips with our little computer. All of us at the Foundation are full of admiration for the year’s achievements; running a magazine isn’t trivial, and with a staff of only volunteers it’s near impossible. That the MagPi is now in a position to start offering print copies (we know of many schools which are buying up bound copies of the first few volumes as a teaching resource) is an extraordinary thing, and we couldn’t be prouder to be associated with them.

Thank you so much, all of you: the writers, editors, layout and graphics, production, distribution team, proofreading army and advertising. The Raspberry Pi would not be where it is today, with about 1.3m units sold, without support from people like you showing everybody what can be done with it. We couldn’t be more grateful.

Blast off game

Here’s another little snippet of video from Mike Cook. This game is one of the projects you’ll be able to make with Raspberry Pi for Dummies (click the link to learn more), by Mike (hardware) and Sean McManus (everything else).

Watching this reminds me that I had a crush on Virgil Tracy when I was about six, despite the fact that he was made of balsa wood.

Kegerface – for all your beer stocking needs

Kegerface is a digital tap list display from SchrodingersDrunk, which you can read more about over on Reddit. It’s an interface for a Kegerator, hence the name. I had to look that up – a Kegerator is a device for dispensing draught beer in the home, involving all kinds of kit like a fridge and a tank full of carbon dioxide. In the picture below, it’s the thing with the spigots sticking out of it.

We, of course, are interested in what’s going on above the spigots.

Click to embiggen

The back-end here is some PHP which interprets data from a shared Google spreadsheet. The whole thing runs off a Raspberry Pi that’s attached to the back of the display. All the information you need is here: the type of beer, the ABV, the hoppiness (scored out of three – that’s what the green glyphs represent), the maker, and, most importantly, how much you have left.

You can find SchrodingersDrunk’s code, along with assets like those hop graphics on Github. The Kegerface is under a CC licence, and other Kegerator owners have been modifying the setup for their own use.

Andy Davies has done a lot of work on his own version. He’s tweaked the interface, and added the bar temperature and a breakdown of how many pints are left in stock; he’s also using MySQL rather than going the CSV/PHP route.

Compare with the interface above, and spot the differences! (Click to enlarge.) We deplore your taste in ginger beer, Andy. Hollows & Fentimans’ hard stuff is much nicer.

Andy’s also made the Kegerface work for bottled beer as well as draught beers, and best of all, has made stock updating easier by attaching an RFID reader to an Arduino, which is then hooked up to the Pi. So every time you take a bottle, you swipe the attached RFID tag across the bar, and the stock is adjusted on the Kegerface. Again, everything’s on GitHub if you want to try building one yourself.

I’m trying to work out whether it’s legal for us to get one of these for the office.

Guest post from Khan Academy Lite

Update: KA Lite dropped us a line to let us know they had a newer version of today’s post ready for us this evening, that they’d prefer us to use. The updated version is below. Enjoy!

Liz: We’ve been talking a bit about Khan Academy Lite on this blog recently. KA Lite is the offline version of Khan Academy, and we’ve recently seen the Kingdom of Bhutan’s first Raspberry Pi being used as a server to give kids offline access to the huge, free suite of Khan Academy’s top-quality video lectures and learning materials. You can read more about Khan Academy on their own website, but don’t just take their word for it: there’s a wealth of material online about the Khan Academy learning experience from users, if you have a few minutes to google for it.

The KA Lite team recently incorporated as a California-based nonprofit organization: Foundation for Learning Equality. They are dedicated to creating tools for the sharing and creation of open-licensed educational content for use by anyone around the world, with special emphasis on reaching the 65% of the world that does not have Internet access, and those with limited-bandwidth, expensive, or unreliable connections.

The KA Lite project emerged during a development internship at Khan Academy in the summer of 2012. Having just received their first eagerly awaited Raspberry Pi, a couple of interns decided to try porting Khan Academy’s educational materials for use on the Raspberry Pi. As a low power device that can run off batteries, solar, or a generator, and its ability to use existing hardware for output (such as old televisions), it is an ideal platform for distributing content to the developing world. After working on “Khanberry Pi” for several weeks, a very simple static file-based version that worked on the Raspberry Pi was presented at a Khan Academy company event in August. The overwhelming enthusiasm about its potential impact led to further brainstorming, while conversations with other organizations using Khan Academy in the developing world reinforced the strong need for a more general software platform for deploying Khan Academy content in offline contexts.

Following brainstorming and feedback from organizations, the design specifications shifted towards a platform that could run on any operating system, on any low-powered hardware (with the Raspberry Pi as an exemplar device), and with mechanisms in place to synchronize data and share new content through any existing channels. Development then began, outside regular working hours, on what became KA Lite, a standalone dynamic web platform that was demoed to Khan Academy at the end of the summer internships in September. In the fall quarter, at UC San Diego, a team of passionate undergraduates, joined later by graduate students, jumped on board to apply their development, design, and user experience skills to build out and improve the platform. In December of 2012, the KA Lite team first announced the open-source project publicly on popular developer channels, and developers around the world soon began contributing and collaborating on the development process, while teachers and organizations in many countries started testing out deployments with their students.

The Raspberry Pi was not only the original inspiration behind the KA Lite project, but continues to be the most cost-effective way to deploy the platform to areas without existing infrastructure. While we had originally envisioned the Pi primarily as a client device, it has proven itself to be an ideal server platform for bringing KA Lite to offline communities. With the addition of a cheap wifi dongle, and a bit of software setup, the Pi is transformed into a standalone wifi access point that can serve up a dynamic web interface to nearby client devices, without the need for internet.

We were unable to swamp the Pi server or its wireless connection even with 35 tablets connecting to it simultaneously.

Inexpensive Android devices, which have been proliferating through the developing world, serve as excellent client devices to connect to a Pi access point. How does the Pi hold up to the task of serving a classroom full of tablet users over a single wifi dongle? We had been warned that a small number of wifi clients would likely swamp the connection, so last week we put it to the test. The Raspberry Pi/Wi-Pi combo held up smoothly, with 35 tablets simultaneously navigating through the KA Lite web interface and streaming Khan Academy videos.

We’re experimenting with alternate power sources, such as the solar-charged d.light that is already in wide distribution through the developing world. The Pi’s low power requirements make this a breeze.

If you’re interested in helping to develop KA Lite or want to deploy it with your students, check out the KA Lite Wiki for more information on how to get involved!

Raspberry Pi, for all your 50s diner needs

Have you ever been to a cafe or restaurant with 1950s jukebox wallboxes in each booth? Wallboxes were an extension for a jukebox, making it more convenient to select music right from your table. You’d drop a coin in, choose a song from the flipbook behind the glass, chrome and plastics, and the machine would send pulses down a wire to the restaurant’s jukebox, where a stepper would decode the pulses and queue up the song you’d picked. Refurbished wallboxes occasionally pop up in mock-50s diners; you’ll also see them for sale on eBay for anything up to a few hundred quid, and people buy them to add to their jukeboxes, or just as home decoration (I’ve seen one being used as a particularly cumbersome phonebook).

Wallbox in situ

Steve Devlin bought himself a couple of wallboxes a few years ago, meaning to hook them up to an MP3 player. He then switched over to a SONOS wireless media system in his house, and forgot about the wallboxes for a couple of years.

Enter the Pi.

On looking at a Raspberry Pi and a wallbox, Steve had an idea. Why not hook the two up together to make a controller for the SONOS system? The Pi decodes the pulses from the box, and sends the information to the SONOS system. (This approach will work with any UPnP protocol, so you’re not limited to using SONOS.)

Steve’s thinking about further customisation: a strip in the box with Radio 4 on it; some dynamic strips like “songs of the week”, which will play a selection of the week’s most-played tunes; some LEDs to show a binary index of common faults, like the wifi being down, or a song not being found.

There are full instructions and much more information on Steve’s website. We think there’s something really compelling about this mix of old and new; thanks for sharing, Steve!

MAKE and MCM Raspberry Pi Design Competition: the winners!

MAKE held a Raspberry Pi Design competition with MCM Electronics for US-based Pi owners, and have just released the results. I’m not sure what’s more impressive: the outstanding quality of the entries, or the fact that even though we spend much of the day furiously googling for new Pi projects, many of the submissions were new to us here at the Foundation. It’s great for us to watch other organisations running contests like this: not least because it’s a real relief not to have to judge them ourselves!

The Grand Prize went to Intonarumori, a collection of magic sound boxes made by a hacker/art collective called urbanSTEW. The STEW-folk say:

Intonarumori is a series of interactive sound boxes created by an art/tech collective, urbanSTEW. The project is based on a century-old futurist movement in which noise-generating machines were created. Inspired by this, urbanSTEW built six new noise machines, each equipped with a Raspberry Pi and various sensors/controls. The boxes are self contained and only need to be plugged in. Intonarumori was presented at a creativity festival where they were played by over 2,000 children/adults.

The Sunlight Foundation’s Lobbyist Meter won the Artistic category: we tweeted about this a while back (and it’s been in my “things to blog” folder for a while) because we thought it was a clever, snarky, funny way to bring attention to a very serious issue. You can read more about the Lobbyist Meter on the Sunlight Foundation’s website. Here it is, doing its transparent, democratic thing.

The Education category award went to a project you’ll all have seen before, if you’re regular readers: Emma Bennett’s beautiful school State Board project (which we have been using in talks as a demonstration of some of the very cool stuff we see kids doing with the Pi) won the prize. Read more about it in the post we wrote when we first saw Emma’s work, and see some video of the board in action below.

Everybody in our offices secretly wants a wooden case for their Pi, because we are all impractical, and we have all read Idoru. The Enclosures category was won by Chris Crumpacker for this beautiful piece of hand-tooled walnut. Chris, if you’re reading, please get in touch. We absolutely, positively need one of these to hold one of the Pis at Raspberry Towers.

Chris told MAKE:

Some times all you need is a bit of scrap wood for inspiration. I had some walnut left over from a previous project. I just love the look of walnut. I had seen other wood cases but they where always 6 pieces of wood glued or nailed together to make a box. I wanted it to be one hunk of wood and my intentions were to carve out a home for the Raspberry Pi.

The final category, Utility, was won by another project we’ve featured here: David Bryan’s cat feeder, which I enjoyed blogging about because it gave me the opportunity to use the phrase “liver-flavoured kibbles”.

Congratulations to all the winners, and thanks to MAKE and MCM for running the competition. You can see the other entries on MAKE’s website – enjoy!