Getting a Measure on Particulates in Stuttgart

There’s a big to-do going on right now in Germany over particulate-matter air pollution. Stuttgart, Germany’s “motor city” and one of Dante’s seven circles of Hell during rush hour, had the nation’s first-ever air pollution alert last year. Cities are considering banning older diesel cars outright. So far, Stuttgart’s no-driving days have been voluntary, and the change of the seasons has helped a lot as well. But that doesn’t mean there’s not a problem.

But how big is the issue? And where is it localized? Or is particulate pollution localized at all? These questions would benefit from a distributed network of particulate sensors, and the OK Lab in Stuttgart has put together a simple project(translated here) to get a lot of networked sensors out into the wild, on the cheap.

The basic build is an ESP8266 with an SDS011 particulate sensor attached, with a temperature and humidity sensor if you’re feeling fancy. The suggested housing is very clever: two 90° PVC pipe segments to keep the rain out but let the dust in through a small pipe. The firmware that they supply takes care of getting the device online through your home WiFi. Once you have it running, shoot them an e-mail and you’re online. If you want help, swing by the shackspace.

We love these sort of aggregated, citizen-science monitoring projects — especially when they’re designed so that the buy-in is low, both in terms of money spent and difficulty of getting your sensor online. This effort reminds us of Blitzortung, this radiation-monitoring network, or of the 2014 Hackaday-Prize-Winning SATNOGS. While we understand the need for expensive and calibrated equipment, it’s also interesting to see how far one can get with many many more cheap devices.

Soda Bottles Used as Heat-Shrink for Wood Joinery

Nobody is likely to confuse it with the beautiful joinery that makes fine furniture so desirable. But as a practical technique, using plastic bottles as heat-shrink tubing for composite joints is pretty nifty, and the pieces produced are not without their charm.

Undertaken as an art project to show people what can be done with recycled materials, [Micaella Pedros]’ project isn’t a hack per se. She started with bottles collected around London and experimented with ways to use them in furniture. The plastic used in soda and water bottles, polyethylene terephthalate (PET), turns out to shrink quite a bit when heated. Rings cut from bottles act much like large pieces of heat-shrink tubing, but with more longitudinal shrinkage and much more rigidity. That makes for a great structural component, and [Micaella] explored several ways to leverage the material to join wood. Notches and ridges help the plastic grip smoother pieces of wood, and of course the correct size bottle needs to be used. But the joints are remarkably strong – witness the classic leaning-back-in-a-chair test in the video below.

Its aesthetic value aside, this is a good technique to file away for more practical applications. Of course, there are plenty of ways to recycle soda bottles, including turning them into cordage or even using them as light-pipes to brighten a dark room.

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Bees in TVs

Bees are a crucial part of the ecosystem – without bees to act as pollinators, many plant species wouldn’t be able to reproduce at all! It’s unfortunate then that bees are struggling to survive in many parts of the world. However, [Louise Cosgrove] is doing her part – building homes for bees in old television sets.

The project started when Louise’s son-in-law left 100 (!) analog TVs at her home, having already recycled the picture tubes. That sounds kind of impolite to us, but we’ll give them the benefit of the doubt and assume they had some sort of agreement. [Louise] realised the empty television cases had plenty of ventilation and would make ideal homes for bees. By filling the empty boxes with natural materials like wood, bamboo and bark, it creates nesting places that the bees can use to lay their eggs.

We’ve seen bees on Hackaday beefore (tee-hee) – like this beehive wired for remote monitoring.

[Thanks to Stuart Longland for the tip!]

Micro Wind Turbine For Hikers

[Nils Ferber] is a product designer from Germany. His portfolio includes everything from kitchen appliances to backpacks. One project, though, has generated a bit of attention. It’s a micro wind turbine aimed at long distance hikers.

Even on the trail, electronics have become a necessity. From GPS units to satellite phones, to ebook readers. Carrying extra batteries means more pack weight, so many hikers utilize solar panels. The problem is that when the sun is up, hikers are on the move – not very conducive to deploying a solar array. The Wind, however, blows all through the night.

[Nils] used carbon fiber tube, ripstop nylon, and techniques more often found in kite building to create his device. The turbine starts as a small cylindrical pack. Deploying it takes only a few minutes of opening panels and rigging guy wires. Once deployed, the turbine is ready to go.

While this is just a prototype, [Nils] claims it generates 5 Watts at a wind speed of 18 km/h, which can be used to charge internal batteries, or sent directly to any USB device. That seems a bit low for such a stiff wind, but again, this is just a prototype. Could you do better? Tell us in the comments! If you’re looking for a DIY wind generator on a slightly larger scale, you could just build one from bike parts.

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Modern Wooden Houses With No Glue Or Nails

Depending where you are in the world, the techniques used to build houses can sometimes seem to be stuck in another century. Bricks and mortar, for instance, we build with them because we are used to them and have a large workforce of people trained to work with them and not much else. But in the 21st century with more advanced building technologies sitting relatively unused and looming housing crises at every turn, does it make sense to still build houses the slow and expensive way our great-grandparents did? Probably not.

Wooden houses are a promising solution to some of the problems outlined in the previous paragraph, and indeed in large parts of the world wood is the housing material of choice. It’s eco-friendly, not too expensive, and can be applied easily to multiple different types of structure. If you think of a wooden house, does the image of a log cabin come to mind, or perhaps a weatherboard house? Both construction methods that would be familiar again to your great-grandparents, so perhaps you might not call it an advanced building technology.

It’s interesting then to see an innovation from France, a system of interlocking wood sections that can be built into walls that look very similar to brick (Here’s the French language original). These are short sections of board cleverly designed with dovetailing to engage with vertical sections that interlock between different courses and leave a gap between wooden inner and outer faces of the wall that can be filled with insulation material. The effect is to create a wooden building system that can produce a vast range of structures that can be assembled in a very short time indeed. This isn’t prefabricated housing, but it delivers the speed you’d expect from it.

They have a video shoving construction of a typical house in rather idyllic French countryside, which we’ve put below the break. It has French language annotations, however for non Français speakers the context is pretty obvious.

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Are You Down With MPPT? (Yeah, You Know Me.)

Solar cells have gotten cheaper and cheaper, and are becoming an economically viable source of renewable energy in many parts of the world. Capturing the optimal amount of energy from a solar panel is a tricky business, however. First there are a raft of physical prerequisites to operating efficiently: the panel needs to be kept clean so the sun can reach the cells, the panel needs to point at the sun, and it’s best if they’re kept from getting too hot.

Along with these physical demands, solar panels are electrically finicky as well. In particular, the amount of power they produce is strongly dependent on the electrical load that they’re presented, and this optimal load varies depending on how much illumination the panel receives. Maximum power-point trackers (MPPT) ideally keep the panel electrically in the zone even as little fluffy clouds roam the skies or the sun sinks in the west. Using MPPT can pull 20-30% more power out of a given cell, and the techniques are eminently hacker-friendly. If you’ve never played around with solar panels before, you should. Read on to see how!

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Mycelia + Sawdust = House?

Take a guess. What is the featured picture for this article? If you’re channeling your inner Google image recognition, you might say: “Best guess for this image: rock.” But, like Google, you’d be wrong. Instead, what you see are bricks made out of fungi obtained from tissues of mycelia.

By taking fungi obtained from tissues of mycelia and storing them in a jar filled with a growth medium (usually sawdust), MycoWorks is creating all sorts of materials with exciting properties. In just three to seven days, the fungi and sawdust mixture expands and forms into clumps of material, which are then used to create products like handbags, purses, bricks, you name it. According to co-founder Phil Ross, “production of this material is similar to making ravioli from scratch, and the final product is more resilient than concrete.”

The resulting materials are buoyant, self-extinguishing and stress dissipating. Moreover, the bricks are alive up until they are put in a kiln. This means bricks that are placed next to each other will grow together, effectively enabling a structure to be made out of just brick, no mortar. And, while they’re not 3D printed, houses made in this fashion have great potential. If these cool new materials have got you excited, and you want to get cozy with the fungus among us, why not go all out with an automated mushroom cultivator?

Video after the break.

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