Shared posts

31 Aug 06:27

Curl.io – Share files from your terminal or ssh

29 Aug 05:29

What People Cured of Blindness See

22 Aug 19:56

Istanbul Is Demolishing 3 New Skyscrapers to Preserve Its Iconic Skyline

by Sarah Zhang

Istanbul Is Demolishing 3 New Skyscrapers to Preserve Its Iconic Skyline

Behind the Blue Mosque in Istanbul rise three stumpy luxury apartment buildings, recently completed and sold—only to be ordered demolished. The ruling from Turkey's highest administrative court to tear down the skyscrapers to protect the city's iconic views is remarkable, if a bit ill-timed.

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22 Aug 20:25

Functional mechanical gear discovered in nature (2013)

27 Aug 04:23

Show HN: Monitorbook – Easily track anything on the web

26 Aug 04:03

Marijuana Law Mayhem Splits U.S. In Two as Travelers Get Busted

23 Aug 10:10

Whale vaginas are amazing

by Cory Doctorow


Mammal penises, including those of cetaceans, are pretty easy to find, while vaginas are more difficult to examine; historically, accounts of animal reproduction have emphasized the features of penises and theories of sperm competition, but a burgeoning scientific emphasis on whale vaginas is revealing structures and strategies that are amazing and wonderful. Read the rest

19 Aug 19:18

Manul – the Cat that Time Forgot

by RJ Evans
Have you ever wanted to take a trip through time to see what animals looked like millions of years ago? When it comes to cats there is little or no need.  This beautiful specimen is a Manul, otherwise known as Pallas’s Cat.  About twelve million years ago it was one of the first two modern cats to evolve and it hasn’t changed since. The other species, Martelli’s Cat, is extinct so what you are looking at here is a unique window in to the past of modern cats.

Although the Manul is only the size of the domestic cat, reaching about 26 inches in length its appearance makes it appear somewhat larger.  It is stocky and has very lengthy, thick fur, which gives it, perhaps to human eyes, an unintentional appearance of feline rotundity.  Yet although it appears stout and somewhat ungainly it has a natural elegance and poise – exactly what you would expect from the genus Felis in other words.  Plus it can certainly look after itself in a fight!

The main reason for its survival throughout the ages has been its isolation. In the wild it lives on the Asian steppes at substantial heights – up to 13,000 feet.  Based in India, Pakistan, western China and Mongolia as well as Afghanistan and Turkemistan, it has even been discovered recently in the wilds of the Sayan region of Siberia. In these places it prefers rocky areas, semidesert and barren hillsides.  In other words places where we are less likely to live – but even having said that you will no doubt be able to hazard a guess which species is the Manul’s greatest enemy.

Take a close look at the eyes of the Manul.  Do you see a difference between it and the domestic cat? That’s right, the pupils of the Manul are round, not slit-like.  Proportionally too, the legs are smaller than cats we know and they can’t run anywhere near as quickly.  As for the ears, well, when you actually can catch sight of them they are very low and much further apart than you would see in a domestic cat.

It also has a much shorter face than other cats, which makes its face look flattened.  Some people, when they see their first Manus mistakenly believe that it is a monkey because of its facial appearance and bulky looking frame.  It is easier to see why, from some angles.

The Manus has not been studied a great deal in the wild, where it is classified as near threatened.  This is because it is distributed very patchily throughout its territory, not to mention the fact it is still hunted despite protection orders made by the various governments who create human law in its range. Before it was legally protected tens of thousands of Manuls were hunted and killed each year, mostly for their fur.

It is thought that the cat hunts mostly at dawn and dusk where it will feed on small rodents and birds. Ambush and stalking are their favorite methods of conducting a hunt and although they tend to shelter in abandoned burrows in the day they have been seen basking in the sun. In other words, behaviorally they are much like the domesticated moggy that we know and love.

The Manul is a solitary creature and individuals do not tend to meet purposefully when it is outside the breeding season and will avoid the company of others of its kind where possible. When it is threatened it raises and quivers the upper lip, Elvis like, revealing a large canine tooth.

When breeding does happen the male has to get in quickly as oestrus usually only lasts just under two days. It usually births up to six kittens, very rarely a single one, and it is believed that the size of its litters reflect the high rate of mortality the infant cats can expect. Yet they are expected to be able to hunt at sixteen weeks and are very much on their own and independent by six months. Although their life expectancy in the wild is unknown in captivity they have lived to over eleven years.

Don’t rush to your local pet store, however.  The Manul does not domesticate and even if it did they are incredibly hard to breed in captivity with many kittens dying.  This is thought to be because in the wild, due to its isolation, the cat’s immune system did not have a need to develop and so when they come in contact with us and other species, this under-developed immune system lets them down.

Yet as a living, breathing glimpse in to twelve million years of feline history these amazing animals are irreplaceable. Unique is a word which, in this day and age, is mightily overused. Yet these cats are quite simply just that – unique.

14 Aug 22:15

How to Sustain a Long-Distance Relationship: 5 Tips I Learned from My WWII Grandpa

by A Manly Guest Contributor

Letters Home 1943

Editor’s note: This is a guest post from Kyle Schaeffer.

In 1942 my grandfather, Peter Stoppi, a young man of 29 years old, joined the army to fight the Nazis during World War II. Like many men his age, he left behind family and friends to serve his country. But when Peter boarded his military boat to Europe, he wasn’t just missing his mother and buddies. He was missing a brand new girlfriend as well.

The primary mode of contact home for a soldier in the 1940s was, of course, the written letter, and over the next three years, my grandfather wrote a 294-page history book’s worth of letters home to the young lady who would eventually become his wife. These letters chronicle a journey across war-torn Europe, the life of an American soldier, and the story of two young people dating across an ocean. More than 70 years later, I turned to these letters for advice in my own long-distance relationship. Though much has changed over the decades, my grandfather’s correspondence gave me five truly timeless tips for any man loving from afar:

1. Frequent Communication is Key

Peter was a great communicator with his girlfriend, Helen. He wrote to her weekly, stayed abreast of events going on back home from her letters, and divulged all the information about his life the military censors would allow. In his letters he talked about the future, his dreams, things he wanted to do on returning to the US, and he even took a little time to tease and flirt with his future wife. For a long-distance relationship in 1942, communication was wide open and clear.

Thankfully, technology has improved leaps and bounds since our grandparents’ time, and men in long-distance relationships today have a host of great tools to keep them connected to loved ones. Products like Skype, FaceTime, and Google Talk allow you to spend time face-to-face with a person. All you need is a webcam and a decent internet connection. Texting apps like WhatsApp and Viber give you the ability to text anyone in the world for free. With so many modes of communication at your disposal, there really is no excuse to lose touch.

But the importance of communication goes deeper than simply talking. You and your loved one must trust each other and address relationship problems or doubts immediately.

2. Maintaining Your Integrity Is More Important Than Ever

Trust is important in any relationship, but once you add the element of distance the importance increases ten-fold. A man must conduct himself in a manner befitting the respect of others around him, and in a way that can reassure his partner of his faithfulness beyond just words.

At night when camped behind front lines, many of Peter’s buddies went into town to drink, see a show, and canoodle with the local young ladies. Peter, however, often stayed behind to write to Helen, expressly telling her about his decision. This may have been a show of social reclusiveness, but the action was also a strong gesture of his commitment to her even from so far away.

Now, should you stay in every night and never see friends or speak to others while away from your significant other? Of course not. But your actions will say more than your mouth. News of your indiscretions travel far faster and easier than they did during the Big One, and are bound to get back to her. Not only that, but the fact that you are even flirting with the idea of stepping out on your gal will unconsciously creep into your voice when you talk to her, sparking mistrust, arguments, and strain in the relationship.

So conduct yourself with integrity, and remember that you are committed to someone even if that person is not physically near you at the moment. If you can’t handle that commitment, then you need to reconsider the relationship.

3. Keep Them Close Even When They Are Far Away

Before he left for Europe, Peter snatched his new love’s class ring, saying he would return it to her after the war. He carried that ring with him every day to remind him of the special girl waiting for him back home. When he did return to the United States, the large gem, standard to any class ring, was missing from its band — a fact Helen, jokingly, never let him forget.

A mutual trinket or piece of jewelry can be a fine way to feel connected to your loved one. In honor of this story, my girlfriend and I each wear a shark tooth around our necks. We dug the teeth for each necklace from the bottom of an aquarium tank while shark diving in South Korea. When I wear the necklace it reminds me of that great moment together in our relationship. Now, when I see my girlfriend wear her shark tooth it is a reminder that she loves me.

4. Have A Plan to Be Physically Near Each Other

My grandparents had no idea when the war would end, if Peter would survive to see that end, or when he would finally be discharged from the army. Despite their inability to control present circumstances, they planned for a future they could control. Peter talked regularly about what he would do when he returned home — his lack of desire to become a miner, his want of children, and all of the dances he and Helen would attend together. Eventually, when he did return home, Peter took up work as a bus mechanic, married his sweetheart, and had a beautiful daughter — all things he planned for and dreamed about with Helen during the war.

Difficult situations are made easier with an end in sight. Have a plan for when you will get back together. Naturally, a specific date is not always possible (as was the case with Peter and Helen), but it is important for both people to work toward the goal of a permanent reunion.

5. You Still Must Live Your Life

Peter demonstrated his integrity by avoiding the bars and wayward ladies of Europe, but he also recognized his duty. At the end of three years of fighting in Europe, he turned his attention to the Pacific and wrote home that he would willingly go on to help finish the war with Japan. He could have pushed for discharge, but he saw that the job was not yet over.

Although this may seem contradictory to number two, it is important to remember that you and your partner live separate lives. No matter how connected you stay, or how involved you are with your partner, you will have different friends, different jobs, different schools, and different activities. You may feel the urge to dedicate all of your time to your partner, but that is impractical and unfair to you.

Be an active participant in your own life. Take time for friends, school, career advancement, leisure, and all of the things that make you an awesome man. An active life will help you relax, feel good about yourself, and will make you more attractive to your partner. After all, no one likes a clingy man-child whose sole reason for life is the person they date.

Peter and Helen Stoppi 1947

Peter and Helen Stoppi married in 1947, built a house, built a family, and remained happily married for 53 years. All of this sprung from a love begun in war-time, maintained across an ocean, and deepened solely through letters over the course of three long years. Dating long-distance is not easy, but a story like that of Peter and Helen Stoppi has much to teach the man who loves someone from any distance, be it a mile or an ocean: success is possible. Just keep on fighting.

What are your tips for sustaining a long-distance relationship? Share them with us in the comments!
__________________________

Kyle Schaeffer is a free-lance writer and college admissions professional at Christopher Newport University in Virginia. Contact him at kyle.schaeffer@ymail.com.

22 Aug 04:00

Loop

Ugh, today's kids are forgetting the old-fashioned art of absentmindedly reading the same half-page of a book over and over and then letting your attention wander and picking up another book.
22 Aug 02:01

The Harvard Classics: Download All 51 Volumes as Free EBooks

19 Aug 16:00

Primeiro capítulo da nova websérie brasileira sobre escalada : Caminhos e Vias de Escalada

by Da Redação

vias de escalada Em um comercial da empresa de computadores e eletrônicos Apple nos anos 80, enaltecia as pessoas inquietas, consideradas desajustadas e que não ficavam esperando sentado e realizaram (se nunca viu, assista aqui)

Se fôssemos classificar Juliana Fachetti, não seria nenhum exagero colocá-la neste grupo de pessoas diferenciadas.

Juliana visualizou que há no Brasil uma demanda reprimida de webséries de qualidade com temática de escalada e universo outdoor.

Hoje no país existem duas webséries o carioca “Trilhas no Rio” e o paulista “RockLog“, mas sem dúvida nenhuma existe espaço para muito mais.

Agregando qualidade e talento a probabilidade de sucesso é grande.

Juliana Falchetti resolveu utilizar imagens e dicas para sua websérie “Caminhos e Vias de Escalada”, que documenta nesta primeira temporada os locais de escalada em Santa Catarina.

Para acompanhar os detalhes da produção, e saber como participar e fazer sugestões acesse : http://www.escaladaemvideo.blogspot.com/

Caminhos-e-Vias-de-Escalada2 Caminhos-e-Vias-de-Escalada1 Caminhos-e-Vias-de-Escalada6 Caminhos-e-Vias-de-Escalada5 Caminhos-e-Vias-de-Escalada4 Caminhos-e-Vias-de-Escalada3

 

 

The post Primeiro capítulo da nova websérie brasileira sobre escalada : Caminhos e Vias de Escalada appeared first on Revista Blog de Escalada.

22 Aug 10:15

Le gène qui permet d'avoir besoin de moins de sommeil

by Grégoire Fleurot
C'est l'une des grandes inégalités au sein de l'espèce humaine: certaines personnes ont absolument besoin de dormir huit heures par nuit sous peine d'être dans un état de fatigue continu et dans l'incapacité de se concentrer plus de cinq minutes d'affilée. D'autres, au contraire, se vantent de n'avoir besoin que de cinq heures de sommeil, et en profitent pour accomplir une grande quantité de tâches au cours de leurs journées de 19 heures. Le chercheur Allan Pack a décidé, au début des années 1980, d'étudier ce phénomène pour savoir si cette différence si injuste entre les hommes était héréditaire. Trois décennies plus tard, il se rapproche de la solution, rapporte la journaliste Maria Konnikova dans le New Yorker. Le chercheur et son équipe ont publié en 2012 les premiers résultats de leurs travaux sur des jumeaux leur permettant d'affirmer que 80% des différences dans la manière dont nous sommes affectés par les effets cognitifs du manque de sommeil s'expliquaient par la génétique. Mais restait à trouver quel gène était responsable. Parallèlement, Ying-Hui Fu, une chercheuse de l'université de Californie, a identifié en 2009 une mutation sur un gène connu pour réguler le rythme circadien chez une mère et une fille qui ne dormaient que six heures par nuit, mais qui n'étaient absolument pas affectées par ce manque de sommeil. En insérant ce gène chez des souris, Ying-Hui Fu a observé que celles-ci se mettaient à dormir moins mais ... Lire la suite
21 Aug 07:41

The Strange and Curious Tale of the Last True Hermit

20 Aug 02:05

Comcast Training Materials Leaked

by Soulskill
WheezyJoe writes: The Verge reports on leaked training manuals from Comcast, which show how selling services is a required part of the job, even for employees doing tech support. The so-called "4S training material" explicitly states that 20 percent of a call center employee's rating for a given call is dependent on effectively selling the customer new Comcast services. "There are pages of materials on 'probing' customers to ferret out upsell opportunities, as well as on batting aside customer objections to being told they need to buy something. 'We can certainly look at other options, but you would lose which you mentioned was important to you,' the guide suggests clumsily saying to an angry customer who doesn't want to buy any more Comcast services." Images of the leaked documents are available on the Verge, making for fun reading.

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20 Aug 05:49

The Free and the Antifree

17 Aug 04:00

August 17, 2014


Only 5 days left to submit for BAHFest!
17 Aug 02:56

Yubari, Japan: a city learns how to die

17 Aug 15:01

Surprising salaries for jobs you’d never imagine

14 Aug 13:43

How I built an audio book reader for my nearly blind grandfather

12 Aug 19:56

Type 225 Words per Minute with a Stenographic Keyboard (Video)

by Roblimo
Joshua Lifton says you can learn to type at 225 words per minute with his Stenosaurus, an open source stenography keyboard that has a not-there-yet website with nothing but the words, "Stenography is about to evolve," on it as of this writing. If you've heard of Joshua it's probably because he's part of the team behind Crowd Supply, which claims, "Our projects raise an average of $43,600, over twice as much as Kickstarter." A brave boast, but there's plenty of brainpower behind the company. Joshua, himself. has a PhD from MIT, which according to his company bio means, "he's devoted a significant amount of his time learning how to make things that blink." But the steno machine is his own project, independent of Crowd Supply. Stenotype machines are usually most visible when court reporters are using them. They've been around since the 1800s, when their output was holes in paper tape. Today's versions are essentially chorded keyboards that act as computer input devices. (Douglas Engelbart famously showed off a chorded keyboard during his 1968 Mother of All Demos.) Today you have The Open Steno Project, and Stenosaurus is a member. And while Joshua's project may not have an actual website quite yet, it has an active blog. And the 225 WPM claim? Totally possible. The world record for English language stenography is 360 WPM. And you thought the Dvorak Keyboard was fast. Hah! (Alternate Video Link)

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11 Aug 04:00

Universal Converter Box

Comes with a 50-lb sack of gender changers, and also an add-on device with a voltage selector and a zillion circular center pin DC adapter tips so you can power any of those devices from the 90s.
03 Aug 10:10

Tashirojima: l'île du Japon où les chats sont rois

by Atlas Obscura
A Ishinomaki, près de Sendai, une traversée en ferry de quarante minutes vous mènera sur l'île de Tashirojima. Si l'île ne compte qu'une centaine d'habitants, ce sont plusieurs centaines de chats qui y ont élu domicile. La domination féline de Tashirojima remonte à la fin de l'ère Edo –entre le milieu du XVIIIe siècle et le milieu du XIXe siècle. A l'époque, les résidents de l'île élevaient des vers à soie pour l'industrie textile. Et les chats étaient précieux tant ils chassaient les souris susceptibles de grignoter les larves. Comme aujourd'hui, Tashirojima était alors une île charriant le gros de ses ressources de l'industrie halieutique. Adulés et protecteurs de la soie, les chats se mirent à traîner autour des pêcheurs pour obtenir de la nourriture et les réactions positives des marins attirèrent bien vite des hordes de minous vers les quais. Une mythologie vit alors le jour au sujets des chats de Tashirojima: pour les pêcheurs, les chats étaient un signe de prospérité et ils leur consacrèrent un temple au centre de l'île.   Si, en 2011, l'île fut dangereusement proche de l'épicentre du séisme de Tohoku –et fut située, de fait, sur la trajectoire du tsunami qui s'ensuivit– Tashirojima, sa population humaine et ses habitants à quatre pattes furent relativement épargnés. Si les bâtiments les plus proches des côtes eurent à subir des dégâts, la plupart des maisons, construites sur les collines, restèrent ... Lire la suite
09 Aug 00:43

My genius friend Rick Rosner went to high school for 10 years

by Mark Frauenfelder
Rick Rosner is my unfathomably weird and wonderful high school friend. I knew he was smart, but it turns out he is the second smartest person in the world, according to a bunch of IQ testing he's taken. He is so unusual that Errol Morris made a documentary about him. Read the rest
08 Aug 17:05

Shortest-known abstract for a serious scientific paper: only 2 words

by Mark Frauenfelder
10 Aug 16:04

One woman can’t have a baby in nine months

09 Aug 21:49

MacBasic

08 Aug 17:00

Five Retro Operating Systems You Can Run on the Raspberry Pi

by Thorin Klosowski

Five Retro Operating Systems You Can Run on the Raspberry Pi

The Raspberry Pi is a great device to experiment on and since it's easy to swap out operating systems on a whim, it's fun to run old ones that you don't have a lot of use for. To that end, here are a few of our favorites.

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30 Jul 21:53

The Wright Stuff: Dirtbagging Is Dead

by Cedar Wright / Photos by John Dickey
The Wright Stuff: Dirtbagging Is Dead

Leo Houlding on Heart Ledges with Tom Morrow.

Sound the alarm! We are on the brink of a great tragedy. Climbing has a dying breed in its ranks, a breed upon which the very foundation of our sport was built: the dirtbag. The golden age of climbing is replete with these anti-heroes: Pratt, Chouinard, and Beckey are our dirtier, more destitute Magic, Bird, and Jordan. But now it would seem dirtbag culture is on the brink of extinction; perhaps destined to go the way of the swami belt or the figure eight belay device.

Many climbers may not even know what a “dirtbag” is, let alone a swami belt, and this is part of the problem. There are some strong, psyched, and promising young climbers who learned or are learning to climb in one of the 889 gyms in America, who might check Webster’s for the word dirtbag and find this: “A dirty, unkempt, or contemptible person.” Arguably, aspects of this short explanation might be true, but here’s a better and more accurate take from Urban Dictionary: “A person who is committed to a given (usually extreme) lifestyle to the point of abandoning employment and other societal norms in order to pursue said lifestyle. Dirtbags can be distinguished from ‘hippies’ by the fact that dirtbags have a specific reason for living communally and generally non-hygienically; dirtbags seek to spend all of their moments climbing.”

When I started climbing at 21, my mentor Sean “Stanley” Leary, who was already an accomplished climber and dirtbag, told me outlandish stories of Yosemite Valley, a mecca not just for climbing, but for dirtbagging, a place where the best climbers lived in their cars (or in caves!), survived on next to nothing, and climbed full-time. Full-time! A seed was planted.

Rest day in El Cap Meadow.

When I arrived in Yosemite, I was warmly welcomed into a close-knit counter-culture with its own values, slang, and lifestyle. There was “The Center of the Universe,” a glorious asphalt slab where the rangers, or “tool” as we called them, looked the other way and allowed climbers to camp in their cars (today it’s a tourist bus lot). If you needed a partner or were feeling social, there would always be a colorful mix of characters in “The Center.” Over time, we began to refer to ourselves as “The Rock Monkeys,” and in retrospect, we were a true force in the history of Yosemite climbing.

First ascents were made, speed records were broken, and climbing gods were born and lived in that dirtbag bastion! I don’t think many of those epic feats would have been possible without the unlimited climbing our alternative lifestyle provided.

And then, as the 2000s rolled in, things started to change in small, but measurable, increments. Rangers began harassing car campers in The Center. Dirtbags were getting busted and ticketed in their secret caves, so they scurried to every corner of the Valley. We would still meet at the Yosemite Lodge Cafeteria for coffee or in El Cap Meadow to smoke weed, but without The Center, our sense of community was increasingly splintered. Even Camp 4 was a no-go with its more and more strictly enforced two-week camping limit. As years went by, and in spite of increasing ranger-induced challenges, I continued to spend most of the year lurking in Yosemite. There was the occasional new dirtbag on the scene, but it was clear that the party was losing steam.

It’s sad; I learned so much as a dirtbag. Toiling on epic in-a-day ascents of El Cap gave me a tremendous work ethic. Living a simple life in the dirt in such a beautiful place inspired a deep love and respect for the natural world. With little money ever to my name, I learned the value of thrift and conservation. While now, I do have more than a thousand dollars in my bank account and an actual roof over my head, I still live life by the dirtbag ethos that collecting experiences is more important than amassing wealth and material objects. I hope Yosemite’s waning dirtbag population isn’t the canary in the coal mine.

Mikey Schaefer on the road in Kentucky in fellow pro climber Matt Segal’s van.

I believe the dirtbag’s long goodbye has a variety of causes. Gas, food, and camping are more expensive every year. Authorities continue to crack down on climbers seeking to live and camp for free. For example, the dirtbag scene in Joshua Tree took a big hit when camping fees and stay limits were introduced at Hidden Valley Campground, where Stonemaster legends like Lynn Hill, John Bachar, and John Long honed their craft in years past.

And then there’s the change in venue of where most modern climbers pick up the sport. The majority of climbers now learn in gyms, disconnected from climbing history. To be clear, I’m not bagging on gyms. Heck, I’ve never been stronger than I am now, living in Boulder and climbing in one regularly, but I do hope that we can connect the gym culture to the deeper thread of climbing history. It’s easy to have respect for your forefathers when you literally walk in their footsteps. In Yosemite, giants like Chuck Pratt, Warren Harding, and Royal Robbins spent chunks of their lives sleeping in the dirt and putting up iconic first ascents on El Cap and Half Dome.

Now you can climb 5.13 without ever going outside. You don’t necessarily need to dedicate your entire life to climbing to get really strong, especially as the majority of climbers turn to bouldering and sport climbing. You don’t learn dirtbag culture in the climbing gym, and it seems that some of the environmental ethics and etiquette that are part and parcel of dirtbagging are getting lost as well.

The Internet has changed the way people climb, too. “You don’t have to hang out in Camp 4 to find partners any more,” my friend and dirtbag stalwart James Lucas half-jokes, “You can go on Mountain Project and find beta and a partner for any climb you want to do!” In an era where many people’s social lives and community exist wholly in the virtual world, climbing is suffering from the same over-arching problem.

Ivo Ninov by El Cap Bridge cleaning cams before setting the speed record on Native Son (5.9 A4) on El Cap, with Ammon McNeely.

Modern culture as a whole is also becoming increasingly materialistic, and being broke and living in your car is just becoming less cool, even for climbers. It’s harder than ever to drop out of the rat race.

End rant. I’ll stop whining and outline something to feel optimistic about. Social norms have a way of ebbing and flowing. Dirtbagging hasn’t flatlined just yet, and the beauty and passion that so many of us find in climbing may be enough to draw in the next generation. That’s where I hope to make a difference. I’m not here to say that every climber should quit their job and move to Yosemite, or start sleeping in their Saturn wagon, but I am here to say that it can change your life.

Consider Alex Honnold. He learned to climb in a gym in Sacramento, and somehow found his way to Yosemite where he dirtbagged in proud style. Slowly but surely, he became one of the greatest climbers the world has ever seen; his simple, meager existence allowed him the time to perfect his big wall skills. The Nose speed record and Half Dome free-solo are only a couple on his endless tick list of notable achievements. I can say confidently that Alex’s life would look a lot different if he hadn’t dropped out of college and made that leap of faith to live in his van and follow his dreams.

Do you have a deferred climbing dream? Do you have a crappy job that makes you miserable? Do you have fantasies of climbing rock every day? Is the only time you find joy and passion in your life when the weekend rolls around and you get to hit the rock? Then you might have what it takes to keep the dirtbag dream alive. Maybe this beautiful, unruly thing has some life in it yet. //

Video: Watch Cedar Wright's short documentary The Last Dirtbag

Cedar Wright is a professional climber and contributing editor for Climbing. He still only showers about once a week or so.

 

07 Aug 17:55

An image-processing robot for RoboCup Junior

by Helen Lynn

Helen: Today we’re delighted to have a guest post from 17-year-old student Arne Baeyens, aka Robotanicus, who has form in designing prize-winning robots. His latest, designed for the line-following challenge of a local competition, is rather impressive. Over to Arne…

Two months ago, the 24th of May, I participated in the RoboCup Junior competition Flanders, category ‘Advanced Rescue’. With a Raspberry Pi, of course – I used a model B running Raspbian. Instead of using reflectance sensors to determine the position of the line, I used the Pi Camera to capture a video stream and applied computer vision algorithms to follow the line. My robot wasn’t the fastest but I obtained the third place.

A short video of the robot in action:

In this category of the RCJ competition the robot has to follow a black line and to avoid obstacles. The T-junctions are marked by green fields to indicate the shortest trajectory. The final goal is to push a can out of the green field.

RPi line follower RPi line follower2 RPi line follower3

This is not my first robot for the RCJ competition. In 2013 I won the competition with a robot with the Dwengo board as control unit. It used reflectance and home-made colour sensors. The Dwengo board uses the popular pic18f4550 microcontroller and has amongst other functionalities a motor driver, a 2×16 char screen and a big, 40pin extension connector. The Dwengo board is, like the RPi, designed for educational purposes, with projects in Argentina and India.

As the Dwengo board is a good companion for the Raspberry Pi, I decided to combine both boards in my new robot. While the Pi does high-level image processing, the microcontroller controls the robot.

The Raspberry Pi was programmed in C++ using the OpenCV libraries, the wiringPi library (from Gordon Henderson) and the RaspiCam openCV interface library (from Pierre Raufast and improved by Emil Valkov). I overclocked the Pi to 1GHz to get a frame rate of 12 to 14 fps.

Using a camera has some big advantages: first of all, you don’t have that bunch of sensors mounted close to the ground that are interfering with obstacles and deranged by irregularities. The second benefit is that you can see what is in front of the robot without having to build a swinging sensor arm. So, you have information about the actual position of the robot above the line but also on the position of the line in front, allowing calculation of curvature of the line. In short, following the line is much more controllable. By using edge detection rather than greyscale thresholding, the program is virtually immune for shadows and grey zones in the image.

If the line would have had less hairpin bends and I would have had a bit more time, I would have implemented a speed regulating algorithm on the base of the curvature of the line. This is surely something that would improve the performance of the robot.

I also used the camera to detect and track the green direction fields at a T-junction where the robot has to take the right direction. I used a simple colour blob tracking algorithm for this.

A short video of what the robot thinks:

Please note that in reality the robot goes a little bit slower following the line.

Different steps of the image processing

Image acquired by the camera (with some lines and points already added):
Image acquired by the camera

The RPi converts the colour image to a greyscale image. Then the pixel values on a horizontal line in the image are extracted and put into an array. This array is visualized by putting the values in a graph (also with openCV):
Visualizing pixel values along a line

From the first array, a second is calculated by taking the difference from two successive values. In other words, we calculate the derivative:
Calculating the derivative

An iterating loop then searches for the highest and lowest value in the array. To have the horizontal relative position of the line in the array, the two position values—on the horizontal x axis in the graphed image—are averaged. The position is put in memory for the next horizontal scan with a new image. This makes that the scan line does not have to span the whole image but only about a third of it. The scan line moves horizontally with the centre about above the line.

But this is not enough for accurate tracking. From the calculated line position, circles following the line are constructed, each using the same method (but with much more trigonometry calculations as the scan lines are curved). For the second circle, not only the line position but also the line angle is used. Thanks to using functions, adding a circle is a matter of two short lines of code.

The colour tracking is done by colour conversion to HSV, thresholding and then blob tracking, like explained in this excellent video. The colour tracking slows the line following down by a few fps but this is acceptable.

HSV image Thresholded image

As seen in the video, afterwards all the scan lines and some info points are plotted on the input image so we can see what the robot ‘thinks’.

And then?

After the Raspberry Pi has found the line, it sends the position data and commands at 115,2 kbps over the hardware serial port to the Dwengo microcontroller board. The Dwengo board does some additional calculations, like taking the square root of the proportional error and squaring the ‘integral error’ (curvature of the line). I also used a serial interrupt and made the serial port as bug-free as possible by receiving each character separately. Thus, the program does not wait for the next character while in the serial interrupt.

The Dwengo board sends an answer character to control the data stream. The microcontroller also takes the analogue input of the SHARP IR long range sensor to detect the obstacles and scan for the container.

In short, the microcontroller is controlling the robot and the Raspberry Pi does an excellent job by running the CPU intensive line following program.

There’s a post on the forum with a more detailed technical explanation – but you will find the most important steps below.

Electrical wiring
Both devices are interconnected by two small boards—one attaches to the RPi and the other to the Dwengo board—that are joined by a right angle header connection. The first does with some resistors the logic level converting (the Dwengo board runs on 5V), the latter board also has two DC jacks with diodes in parallel for power input to the RPi. To regulate the power to the Pi, I used a Turnigy UBEC that delivers a stable 5.25V and feeds it into the Pi by the micro USB connector. This gives a bit more protection to the sensitive Pi. As the camera image was a bit distorted I added a 470uF capacitor to smooth things out. This helped. Even though the whole Pi got hot, the UBEC stayed cold. The power input was between 600 and 700mA at around 8.2 volts.

Grippers
Last year, I almost missed the first place as the robot only just pushed the can out of the field. Not a second time! Having this in thought, I constructed two 14cm long arms that could be turned open by two 9g servos. With the two grippers opened, the robot spans almost 40 centimetres. Despite this, the robot managed—to everyone’s annoyance—‘to take its time before doing its job’, as can be seen in the video.

Building the robot platform
To build the robot platform I followed the same technology as the year before (link, in Dutch). I made a design in SketchUp, then converted it to a 2D vector drawing and finally lasercutted it at FabLab Leuven. However, the new robot platform is completely different in design. Last year, I made a ‘riding box’ by taking almost the maximum dimensions and mounting the electronics somewhere on or in it.

This time, I took a different approach. Instead of using an outer shell (like insects have), I made a design that supports and covers the parts only where necessary. The result of this is not only that the robot looks much better, but also that the different components are much easier to mount and that there is more space for extensions and extra sensors. The design files can be found here: Robot RoboCup Junior – FabLab Leuven.

3D renders in SketchUp:

RCJ_Robot_2014_render3 RCJ_Robot_2014_render5

On the day of the RCJ competition I had some bad luck as there wasn’t enough light in he competition room. The shutter time of the camera became much longer. As a consequence, the robot had much more difficulties in following sharp bends in the line. However, this problem did not affect the final outcome of the competition.

Maybe I should have mounted some LEDs to illuminate the line…