How to see the International Space Station (ISS)

Last weekend me and my wife were down in Eindhoven in the south of what was a very sunny and warm Netherlands. While visiting a friend down there we discovered they have a telescope. Oh, I was so excited! For many years, having a telescope has been a dream of mine but alas… they aren’t exactly cheap instruments and I always had the feeling it would be something that would get old pretty fast.

However, as soon as I had the chance to point the telescope at the tiny shiny blimp in the sky which turned out to be Saturn, and as soon as I was able to see its rings hanging around its spherical mass of gas, I was in love. “Wait, let’s point it at the moon!” – and I was even more in love. Somehow there is some astronomic quality and reality to seeing things through that glorified mirror-lined tube that photos simply cannot capture. Much the same way a single photograph cannot capture the greatness of the Great Wall, much the same way photos cannot describe the feeling of a plane banking to 30 degrees inclination to pull you out of the floor, out to 39000 feet to take you places… astronomic photographs, as spectacular and colorful as they may be, cannot describe the feeling of DIY pointing the telescope and sitting there looking, wondering, imagining.

This means, of course, one thing: for the next few months I will be badgering my wife, trying to persuade her to allow me to invest in a good telescope.

Part of this persuasion started last night when the ISS was flying past us at its incredible speed. Normally the ISS would only be visible in the wee hours of the night and we would have to wait for the right day where all the conditions were met. You need a clear sky, the station to be passing around your area and patience to wake up in the middle of the night to see it. But last night at 23:13 would be a perfect time to spot it. Our plan was almost foiled by the patchy clouds which were planning to ruin the fun but a couple of minutes past the announced time, there it was, in all its glory. A small patch of reflected light, in total size bigger than any star, bigger indeed than any planet  and about as big as one of the planes which usually make for the Rotterdam/The Hague airport around the same area. But this one was different. It was not blinking but rather reflecting light, constantly so, and flying at a different bearing than of the planes. Hiding here and there behind one of the clouds, it was as visible as it could be in the sky which at that time was not yet so dark. In effect, as I recall, the sky’s light night blue was probably the best to spot the station. Too dark and the station’s colors would get lost in the background, too light and it is simply not visible at all, overexposed by the sunlight. It’s pretty tough to find a photo of what we saw last night, mostly because spotting the ISS with the naked eye requires conditions which are very adverse to photography (darkness + fast moving objects) so here’s a photo of the ISS in all its glory (photo courtesy of Wikipedia):


This was it, this was yet another step towards my space exploration. Yet another step in convincing my wife the 300 euro I need for a telescope will be worth it.

Oh yeah, my post’s title was about how to see the ISS, right? Oh that’s pretty easy… If you have a smartphone, specifically Android, you can use the ISS Detector app. Fill in your location and you’re good to go. Otherwise just head over to NASA’s very own “Spot the Station”: . It’s really worth it and you should definitely give it a go.

EDIT: Last night we were “station spotting” again and I managed to snap a picture of the ISS in all its glory. In a surprisingly clear sky, I feel that the photo does not make justice to the real thing but indeed, it is better than nothing!

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[Project] How to easily monitor your plants’ soil humidity

You came here to learn about soil humidity monitoring, right?

Then you should probably scroll down to the part where I have a photo of my setup. However, if you have the time and feel like reading some of my ramblings, why don’t you just continue with the next paragraph? I promise you won’t be disappointed!

My beginning as an urban farmer

Spring is here and with it comes the sunshine, even in rainy Netherlands. For this reason I recently started growing all kinds of things at home. First I started with some of those tiny thumb-sized vases which come bundled with sunflower and lavender seeds but… soon after, I realized those vases were not gonna be big enough to hold that many seeds. Determined to see those plants through to flowering, I started buying bigger vases and soil. Soon after that, I was growing not only the sunflowers and lavender but I sowed some seeds I had bought a long time ago. I was now growing several shoots of mimosa pudica (aka the shy plant, famous for the fact that it closes its leaves when you poke it – which you can see on Youtube), a few more seedlings of chinese chives (or scientifically speaking, allium tuberosum, delicious in many dishes) and my proudest plantation, seedlings of the hottest pepper in the world: the trinidad moruga scorpion, which in the the Scoville scale is said to be approximately 500 times hotter than your average Jalapeño or Chipotle chilli. Now THAT’S spicy!

You like the post so far? Well keep on reading then!

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How to get the TP-Link TL-WN725N working on Raspberry Pi

Recently I bought two TP-Link TL-WN725N adapters off Amazon. They’re cheap and according to the RPi peripherals list [here], are supposed to work well under Linux. They do, however, require a special driver which is not included in the Linux kernel itself. This leaves you with two options:

- Use one of MrEngman’s pre-compiled kernel modules which is available on the Raspberry Pi forums [here] (kudos to MrEngman to his ongoing effort!).


- You compile your own kernel module.

However, keep in mind the following very important caveat: whatever your choice is, this process requires some basic knowledge of Linux! If you don’t feel comfortable messing around with kernel modules and such, I would recommend that you proceed with caution and maybe even ask a more experienced friend to give you a hand. It’s unlikely you will ruin your Raspberry Pi but you may very well ruin your installation. PROCEED WITH CAUTION.

Now, be aware that if you just want your wifi up and running and don’t want to be bothered, you really should take the easy way out here and check whether MrEngman has a pre-compiled module that’s been compiled with the same revision of your kernel. If you cannot find one or if you’re feeling especially brave, read on for the step by step on how to compile it yourself.

Also keep in mind that this tutorial applies to the Raspbian distribution. It may (or may not) work in Pidora (and others) but it’s up to you to adjust accordingly.

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Chronopost Portugal? Serviço enganador…

This post will, extraordinarily, be in Portuguese as it is a complaint and a warning towards a Portuguese courier company which is indulging in false advertising. This is, therefore, a warning for my fellow Portuguese countrymen.

Esta é uma história de como os meus pais, na segunda-feira passada (dia 7 de Outubro de 2013) me enviaram pela Chronopost Portugal uma encomenda para a Holanda, onde me encontro a residir. No site, a Chronopost anuncia o serviço Chronopost Classic onde prometem entregas para a Europa dentro de 3~4 dias a preços convidativos (24 euros até 10 kg).

Uma vez que a relação preço versus qualidade (anunciada) parecia bastante boa, decidi escolher o serviço da Chronopost.

Qual não é o meu espanto quando hoje, dia 11 de Outubro de 2013, passados 4 dias da expedição da encomenda, esta ainda não se encontra sequer na Holanda (de acordo com o track and trace). Depois de contactar por várias vezes a Chronopost e me terem sido dadas desculpas de que “os 4 dias são 4 dias de trânsito” e de que “o dia de expedição não conta”, o facto continua a ser de que excluindo o dia de expedição, faz hoje 4 dias desde que a encomenda se encontra em trânsito.

Após ter descoberto que não vai ser a Chronopost que me vai entregar a encomenda mas sim um dos seus parceiros (a DPD), decidi contactar também esta empresa afim de tentar obter um esclarecimento sobre quando a encomenda será entregue. Estes senhores dizem-me que será entregue apenas na segunda-feira, sete dias depois da expedição.

Fica aqui então o aviso que a Chronopost Portugal está a enganar os seus clientes com um serviço de pouca fiabilidade, prometendo entregas em 4 dias e fazendo-as em 7 dias. Conhece algum serviço mais fiável? Que tal deixá-lo então na secção de comentários em baixo?

Automatic Recovery of REST Interfaces

Recovery of REST interfaces is an interesting research topic which came into conversation with one of our industrial partners and which I would like to explore. This is also something mentioned by Maleshkova et al in their work on “Investigating Web APIs on the World Wide Web” (pre-print, IEEE citable). The authors claim that “two thirds of the APIs do not state the data-type of the input and 40% of the APIs do not state the HTTP method. If a standard interface description language, such as WSDL, [was] used [...] this would be unthinkable”.

This is very true. Read on to know more.

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Ok, I got some kefir, now what? (or Kefir Quickstart Guide)

My last post introduced the wonders of kefir and the magic grains that ferment milk into delish yoghurt. Some people have asked me for grains and right now I actually have a “customer” on hold for my kefir grains to grow again so I can give them away. It seems my friends are more open than I was actually expecting! Nice!

My own kefir grains!

My own kefir grains!

Read on for the essential tips on getting quickstarted with kefir making!

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Would you like some Kefir? Like some what?!

Not long ago my father had mentioned this thing called ‘kefir’ with which you could apparently make yoghurt. At the time I didn’t pay much attention and he, despite mentioning that this kefir thing could be obtained for free (or just by paying postage), didn’t make much of it either. It was not until recently, when I travelled to Russia (where it is very popular) that I finally got in close contact with ‘kefir’.

Read on to learn more about kefir.

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WeChat Pebble – WeChat notifications on your Pebble!

As the Pebble smartwatch is becoming more and more mainstream, so is the need for supporting a wider range of messaging applications. While much of the Western world does not know about WeChat, surely everyone has at some point or another heard of WhatsApp or Blackberry Messenger. Well, WeChat is very much the same thing but it’s the most popular mobile instant messaging chat in China with over 300 million users! The single one feature that makes WeChat unique is having a walkie-talkie feature in its very core. At the literal push and release of a single button, WeChat users can send voice messages to each other, thus avoiding all the trouble of typing.

Because WeChat is popular in China, it is bound to push notifications which include Chinese characters. These characters are currently not supported in the Pebble (it uses Unicode for character encoding but due to space restriction it does not include fonts for characters beyond the Latin alphabet) and WeChat Pebble also takes this issue out of the way.

Adding a font with 2000~3000 characters seems to be troublesome due to severe space restrictions in the Pebble firmware. Therefore, I came up with an approach which makes use of the Unifont character library to render messages on the Android app and send them to the Pebble watch as a bitmap. This effectively solves the problem not only for Chinese but also for Russian, Hebrew, you name it!

WeChat Pebble in action!

WeChat Pebble in action!

All of this is available as open-source and for free.

-> If you are a developer, read past the installation steps for some hardcore open-source goodies

-> If you just want to use this and don’t care about the source code, just read the following two simple steps!

1 – Install the Android app available in the Play Store here or by scanning the QR code below.

NOTE: For the app to actually push the WeChat notifications you have to first start the app and follow the instructions. Also keep in mind that in the Settings you can choose different types of notifications.

Play Store

Play Store

(N.B. If for some reason you cannot access the Android Play Store, the .apk is also available directly from my website by clicking here.)


2 – Install the Pebble watchapp by installing this .pbw or by scanning the QR code below.

Pebble Watch App (.pbw)

Pebble Watch App (.pbw)


After this you’re pretty much done! Just enjoy and feel free to drop me a comment below or visit the Pebble forums’ here! I will keep updating this post with news on the WeChat Pebble app.

The source code is available for free on GitHub:

Now running off a Raspberry Pi!

During my recent trip to the UK I indulged myself in buying a Raspberry Pi. There’s just so many things you can do with one that my initial plan of having it as an XMBC media center in our living room was quickly subdued by the rush to run my blog off it.

Lo and behold! Here it is!

This blog now proudly runs off the Raspberry Pi in the photo below. Neat, hey?!

The mint plant in the background goes hand in hand with the RPi's green nature at only 3.5W input!

The mint plant in the background goes hand in hand with the RPi’s green nature at only 3.5W input!

My next plan, with the money I’ll save from not paying for hosting, is to buy at least one more (I actually want to buy two more but shh! Don’t tell my wife!) to serve as my own personal mail server. With the free version of Google Apps going the way of dinosaurs and even though current users can still use the service, it’s pretty clear we’re second class customers and rather than waiting until we’re pushed to pay, I’d rather be more proactive and switch on my own timing. In all honesty, after the recent news on Lavabit I’m starting to grow more and more afraid of having my private data based off US servers, so Raspberry Pis it is!

Silicon Valley and Mozilla (or The Story of How I started Using Firefox Again)

My blog writing continues being as sporadic as sporadic can be, and it kind of saddens me because writing still is very much a passion for me.

This time I come to you, my readers, with an exciting trip I recently took to Silicon Valley with a group of entrepreneurs from Delft’s University of Technology. In this trip I had the opportunity of meeting many different interesting people from all walks of life. People with different life experiences that ranged from an ex-con to people who had successfully started their own tech company. Amongst all these people, there was one that really stood out for me, and that was Pascal Finette who you might or not know. Pascal is something at Mozilla. To be frank, I didn’t actually get what’s his official position but in the grand scheme of things, it didn’t really matter. As a matter of fact, I think that’s part of the take home message from the presentation Pascal gave us. What you do matters much more than what you say.

In many ways, Pascal’s talk was inspiring. Somehow I had this prejudice that Mozilla (and Firefox, more specifically) was a dying brand/company, but this view changed as soon as I stepped into their offices in Silicon Valley and started hearing about their core values. Many a times we hear the cliche “there’s no free lunch”, but if there is such a thing as free lunch, then that’s what Mozilla is doing for us and they’re doing it for the sake of it. Truly for free. Looking at what Mozilla does from a truly objective perspective, it kinda feels like Mozilla is the Mother Theresa of the software world. And don’t take me wrong, there are many such companies out there, but Mozilla in particular inspires me for how they defined their core values and for how they juggle so well their position as a company that needs to be kept financially afloat and as an ultimately open-source organization which relies (as far as I understand) solely on no one but themselves and a bunch of people who contribute with labor and money.

I’m an open-source advocate, but that doesn’t mean I’m an open-source monkey. I’m that kind of guy who knows the value of open-source but not the kind of guy who uses open-source exclusively just because it’s open and free. Open-source is great and many open-source projects stand shoulder to shoulder with their paid counterparts but for many things still, the paid alternatives are just better. Being a contributor to open-source myself I’m able to see the value in it while at the same time realizing that sometimes, you just have to pay to have software that makes your life easier (e.g. give me Photoshop over Gimp, anytime).

There’s also a long standing “joke” in the open-source world, in that most non-tech people actually don’t know what’s open-source. They don’t know the difference between free and “libre” (“libre”, being a Spanish word for the other kind of free which seemingly the English language cannot describe, became famous for its inclusion in the name LibreOffice – a branch of OpenOffice that’s, well, truly open, free and libre).  Naturally, many people would describe Chrome as free, or Facebook even. What they don’t know is that whenever they use either of these products, they are paying with one of their most precious possessions: their privacy.

I don’t want to get into legal trouble here, and for the most part I like to think of Google as mostly benevolent (but a corporation nonetheless). However, if you truly want to stick it to the man and use something that is pure free and no strings attached to any corporation that makes money off you, go Mozilla; go Firefox. The browser is not worse than Chrome, and this is the story of how they conquered me back. Through one talk by Pascal Finette.