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An affordable ocular fundus camera

via Raspberry Pi

The ocular fundus is the interior surface of the eye, and an ophthalmologist can learn a lot about a patient’s health by examining it. However, there’s a problem: an ocular fundus camera can’t capture a useful image unless the eye is brightly lit, but this makes the pupil constrict, obstructing the camera’s view. Ophthalmologists use pupil-dilating eye drops to block the eye’s response to light, but these are uncomfortable and can cause blurred vision for several hours. Now, researchers at the University of Illinois at Chicago have built a Raspberry Pi-based fundus camera that can take photos of the retina without the need for eye drops.

Dr Bailey Shen and co-author Dr Shizuo Mukai made their camera with a Raspberry Pi 2 and a Pi NoIR Camera Module, a version of the Camera Module that does not have an infrared filter. They used a small LCD touchscreen display and a lithium battery, holding the ensemble together with tape and rubber bands. They also connected a button and a dual infrared/white light LED to the Raspberry Pi’s GPIO pins.

When the Raspberry Pi boots, a Python script turns on the infrared illumination from the LED and displays the camera view on the screen. The iris does not respond to infrared light, so in a darkened room the operator is able to position the camera and a separate condensing lens to produce a clear image of the patient’s fundus. When they’re satisfied with the image, the operator presses the button. This turns off the infrared light, produces a flash of white light, and captures a colour image of the fundus before the iris can respond and constrict the pupil.

This isn’t the first ocular fundus camera to use infrared/white light to focus and obtain images without eye drops, but it is less bulky and distinctly cheaper than existing equipment, which can cost thousands of dollars. The total cost of all the parts is $185, and all but one are available as off-the-shelf components. The exception is the dual infrared/white light LED, a prototype which the researchers explain is a critical part of the equipment. Using an infrared LED and a white LED side by side doesn’t yield consistent results. We’d be glad to see the LED available on the market, both to support this particular application, and because we bet there are plenty of other builds that could use one!

Read more in Science Daily, in an article exploring the background to the project. The article is based on the researchers’ recent paper, presenting the Raspberry Pi ocular fundus camera in the Journal of Ophthalmology. The journal is an open access publication, so if you think this build is as interesting as I do, I encourage you to read the researchers’ presentation of their work, its possibilities and its limitations. They also provide step-by-step instructions and a parts list to help others to replicate and build on their work.

It’s beyond brilliant to see researchers and engineers using the Raspberry Pi to make medical and scientific work cheaper and more accessible. Please tell us about your favourite applications, or the applications you’d develop in your fantasy lab or clinic, in the comments.

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Build the wall: a huge wall (of LEDs)

via Raspberry Pi

London-based Solid State Group decided to combine Slack with a giant LED wall, and created a thing of beauty for their office.

Solid State LED wall Raspberry Pi

“BUILD THE WALL we cried aloud. Well, in truth, we shouted this over Slack, until the pixel wall became a thing.” Niall Quinn, Solid State Group.

Flexing the brain

Project name RIO: Rendered-Input-Output took its inspiration from Google Creative Lab’s anypixel.js project. An open source software and hardware library, anypixel.js boasts the ability to ‘create big, unusual, interactive displays out of all kinds of things’ such as arcade buttons and balloons.

Every tech company has side projects and Solid State is no different. It keeps devs motivated and flexes the bits of the brain sometimes not quite reached by day-to-day coding. Sometimes these side projects become products, sometimes we crack open a beer and ask “what the hell were we thinking”, but always we learn something – about the process, and perhaps ourselves.

Niall Quinn, Solid State Group

To ‘flex the bits of the brain’, the team created their own in-house resource. Utilising Slack as their interface, they were able to direct images, GIFs and video over the internet to the Pi-powered LED wall.

Solid State LED wall Raspberry Pi

Bricks and mortar

They developed an API for ‘drawing’ each pixel of the content sent to the wall, and converting them to match the pixels of the display.

After experimenting with the code on a small 6×5 pixel replica, the final LED wall was built using WS2812B RGB strips. With 2040 LEDs in total to control, higher RAM and power requirements called for the team to replace their microcontroller. Enter the Raspberry Pi.

Solid State LED wall Raspberry Pi

“With more pixels come more problems. LEDs gobble up RAM and draw a lot of power, so we switched from an Arduino to a Raspberry Pi, and got ourselves a pretty hefty power supply.”

Alongside the Slack-to-wall image sharing, Solid State also developed their own mobile app. This app used the HTML5 canvas element to draw data for the wall. The app enabled gaming via a SNES-style controller, a live drawing application, a messaging function and live preview capabilities.

Build your own LED wall

If you’re planning on building your own LED wall, whether for an event, a classroom, an office or a living room, the Solid State team have shared the entire project via their GitHub page. To read a full breakdown of the build, make sure you visit their blog. And if you do build your own, or have done already, make sure to share it in the comments below.

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The All-Seeing Pi: a Raspberry Pi photo booth

via Raspberry Pi

Have you ever fancied building a Raspberry Pi photo booth? How about one with Snapchat-esque overlay filters? What if it tweeted your images to its own Twitter account for all to see?

The All-Seeing Pi on Twitter

The All Seeing Pi has seen you visiting @Raspberry_Pi Party @missphilbin #PiParty

Introducing The All-Seeing Pi

“Well, the thing I really want to say (if you haven’t already) is that this whole thing was a team build”, explains one of the resource creators, Laura Sach. “I think it would be a brilliant project to do as a team!”

The All-Seeing Pi Raspberry Pi Photo Booth

The resource originally came to life at Pycon, where the team demonstrated the use of filters alongside the Camera Module in their hands-on workshops. From there, the project grew into The All-Seeing Pi, which premiered at the Bett stand earlier this year.

The All-Seeing Pi on Twitter

The All Seeing Pi has seen you, @theallseeingpi #PiatBETT #BETT2017

Build your own photo booth

To build your own, you’ll need:

  • A Camera Module
  • A monitor (we used a touchscreen for ours)
  • Two tactile buttons (you can replace these later with bigger buttons if you wish)
  • A breadboard
  • Some male-female jumper leads

If you’re feeling artistic, you can also use a box to build a body for your All-Seeing Pi.

By following the worksheets within the resource, you’ll learn how to set up the Camera Module, connect buttons and a display, control GPIO pins and the camera with Python code, and how to tweet a photo.

The All-Seeing Pi Raspberry Pi Photo Booth

Raspberry Pi Foundation’s free resources

We publish our resources under a Creative Commons license, allowing you to use them for free at home, in clubs, and in schools. The All-Seeing Pi resource has been written to cover elements from the Raspberry Pi Digital Curriculum. You can find more information on the curriculum here.

Raspberry Pi Digital Curriculum

 

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Harry Potter and the Real-Life Wizard Duel

via Raspberry Pi

Walk around the commons of Cambridge and you’re bound to see one or more of the Cambridge University Quidditch Club players mounted upon sticks with a makeshift quaffle. But try as they might, their broomsticks will never send them soaring through the air.

The same faux-wizardry charge can’t be levelled at Allen Pan‘s Real-Life Wizard Duel. For when the wand-wielding witches or wizards cast one of four Harry Potter spells, their opponent is struck accordingly… as if by magic.

Real Life Wizard Duel with ELECTRICITY | Sufficiently Advanced

Body shocking wands with speech recognition…It’s indistinguishable from magic! Follow Sufficiently Advanced! https://twitter.com/AnyTechnology https://www.facebook.com/sufficientlyadvanced https://www.instagram.com/sufficientlyadvanced/ Check out redRomina: https://www.youtube.com/user/redRomina Watch our TENS unit challenge! https://youtu.be/Ntovn4N9HNs These peeps helped film, check them out too!

Real spells, real consequences

Harry Potter GIF

Allen uses Transcutaneous Electrical Nerve Stimulation (TENS) machines to deliver the mighty blows to both himself and his opponent, setting off various sticky pads across the body via voice recognition.

The Google Cloud Speech Recognition API recognises one of five spells – Expelliarmus, Stupefy, Tarantallegra, Petrificus Totalus, and Protego – via a microphone plugged into a Raspberry Pi.

Harry Potter GIF

When the spell is pronounced correctly and understood by the Pi, it tells an Arduino to ‘shoot’ the spell out of the wand via an infrared LED. If the infrared receiver attached to the opponent recognises the spell, it sets off the TENS machine to deliver an electric current to the appropriate body part. Expelliarmus, for example, sets off the TENS connected to the arm, while calling out a successful Petrificus Totalus renders the opponent near immobilised as every pad is activated. For a moment’s rest, calling out “Protego” toward your own infrared receiver offers a few moments of protection against all spells aimed in your direction. Phew.

“But people only die in proper duels, you know, with real wizards. The most you and Malfoy’ll be able to do is send sparks at each other. Neither of you knows enough magic to do any real damage. I bet he expected you to refuse, anyway.”
“And what if I wave my wand and nothing happens?”
“Throw it away and punch him on the nose,” Ron suggested.
Harry Potter and the Philosopher’s Stone

Defence Against the Dark Arts

Harry Potter Wizard Duel Raspberry Pi

To prevent abuse of the spells, each one has its own recharge time, with available spells indicated via LEDs on the wand.

In the realm of Harry Potter fan builds, this has to be a favourite. And while visitors to The Wizarding World of Harry Potter may feel the magical effect of reimagined Butterbeer as they wander around Hogsmead, I’d definitely prefer to play Real Life Wizard Duel with Allen Pan.

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Pi Wars 2017 is just a few days away!

via Raspberry Pi

On 1-2  April, Cambridge Raspberry Jam will be hosting Pi Wars 2017, the latest iteration of their successful robotics challenge competition.

For those unfamiliar with the setup, Pi Wars contestants use home-brew Raspberry Pi-powered robots to compete across seven challenge courses. There’s also a host of other categories, including prizes for Artistic and Technical Merit, as well as an award for ‘Funniest Robot’!

With only a few days to go until the big weekend, we’ve wrangled Pi Wars 2017 hosts, Mike and Tim, to give us the lowdown on everything you need to know before the main event.

Pi Wars 2015 obstacle course Pi Wars 2017

Crowds gather around the Obstacle Course from the 2015 competition

Pi Wars 2017

This is the third time the competition has been run, and this time we’re running the event over two days:

  • Saturday – School teams.
  • Sunday – Beginner, Intermediate and Pro/Veteran teams.

With teams coming all the way from the USA, Germany, Switzerland, Wales and Scotland as well as England, it truly is an international competition! There are more than 65 teams competing across the weekend. Judging by some of the tweets we’ve been seeing, there’s likely to be some fierce competition!

Special guest and head judge

Doctor Lucy Rogers Pi Wars 2017

Lucy rightly running from House Robot, Sir Killalot, on the set of BBC Robot Wars

We are very fortunate to welcome BBC Robot Wars judge Dr. Lucy Rogers as our special guest and head judge. Away from Robot Wars, Lucy is an independent designer and maker, and famously introduced Raspberry Pi-controlled animatronics to the Blackgang Chine theme park on the Isle of Wight.

Get tickets, come along and watch the action

If you’re in the Cambridge area, or even if you’re further afield, you can come along and watch. Pi Wars 2017 spectator tickets are available from Eventbrite. Children aged 16 and under go free, as do volunteers, and it’s just £5 per day (or £7 for the whole weekend) for everyone else.

What else is happening?

In addition to the competing teams, there will be plenty of show-and-tell tables featuring robotics projects, plus an extensive marketplace featuring your favourite vendors.

Where is it?

The event takes place at the Cambridge Computer Laboratory (William Gates Building). There is free parking a (very) short walk away, and there is catering on site (or bring a packed lunch!). It’s a nice family-friendly day out. You can chat to the stall holders and teams (when they’re not running between challenges!), and generally find out what is possible with the Raspberry Pi, some robotics components, a healthy dose of programming and a maker’s mindset!

The William Gates Building Pi Wars 2017

The William Gates Building

What have we been doing to prepare?

Tim has been hard at work designing and building courses for our seven challenges, which are:

  • Straight-line speed test (autonomous) – get down the course as fast as possible without touching the walls.
  • The minimal maze (autonomous) – get around the maze without touching the walls.
  • The line follower (autonomous) – follow the black line for as many circuits as possible.
  • Slightly deranged golf (remote-controlled) – a beautiful, mystery course that will have a special component added to it by Pi Borg!
  • The obstacle course (remote-controlled) – who knows what’s in store this year?
  • Skittles (remote-controlled) – knock the pins down, score points.
  • Pi Noon – the robot vs robot duel (remote-controlled) – pop the other robot’s balloon before the time runs out.
Pi Wars 2015 Pi Noon competition Pi Wars 2017

2015’s Pi Noon competition

Find out more about the courses and the rules on the Pi Wars 2017 website.

Mike has been fiercely sending out emails to competitors, exhibitors, volunteers, vendors and our wonderful Pi Wars 2017 sponsors, without whom we would be unable to run the event. He’s also busy constructing individual timetables for each team, so everyone knows exactly where they need to be for their challenge runs.

We’re really looking forward to the weekend – it’s all coming together, and with the help of our volunteers, you can be assured of a warm welcome to the venue. So, grab your tickets and prepare for an epic showdown between dozens of robots, all powered by your favourite single-board computer!

The future of Pi Wars

There is an upcoming Pi Wars-style competition in Pennsylvania, USA on 3 June (The MagPi Magazine published a blog about this today), and we’re expecting another USA competition at some point, as well as a possible Pi Wars Scotland. As for the future of the Cambridge-based event? Let’s get this one out of the way first!

Any questions? The best way to contact us is via the Pi Wars 2017 website. Alternatively, give us a shout on Twitter!

Mike and Tim

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Selectively silence a landline phone with Arduino

via Arduino Blog

Silencing a smartphone at night isn’t difficult, but if you have a landline, Arduino can help!

Before computer hacking/modding became accessible, the next best thing was to creatively explore the phone system via custom electronics. Though this pursuit, known as “phone phreaking,” has largely gone away, some people still have landlines. As “MolecularD” shows in this Instructables writeup, with a few components you can creatively trick your phone into not ringing on your end, while appearing to the caller to simply ring and ring as if no one is home.

In order to make it much more useful, MolecularD hooked up an Arduino Mega with a real-time clock module to turn the device on and off depending on the time of day. Now calls from phone solicitors, or “IRS agents” at 4 in the morning can be eliminated automatically. As noted, this may or may not be legal where you live, so attempt it at your own risk!