Perfecting The Solar Powered Web Server

October 8, 2018 by Tom Nardi 35 Comments

Running a server completely off solar power seems like it would be a relatively easy thing to do: throw up a couple of panels, tack on a charge controller and a beefy battery, and away you go. But the reality is somewhat different. Most of us hackers are operating on a relatively limited budget and probably don’t have access to the kind of property you need to put out big panels; both pretty crippling limitations. Doing solar on a small-scale is hard, and unless you really plan ahead your setup will probably be knocked out on its first cloudy day.

So when [Kris de Decker] wanted to create a solar-powered version of his site “Low-tech Magazine”, he went all in. Every element of the site and the hardware it runs on was investigated for potential power savings, and luckily for us, the entire process was written up in meticulous detail (non-solar version here). The server still does go down from time to time if the weather is particularly poor, but in general it maintains about 90% uptime in Barcelona, Spain.

The solar side of the equation is fairly simple. There’s a 50 watt photovoltaic panel charging a 12V 7Ah lead-acid battery though a 20A charge controller. With an average of 4 to 6 hours of sunlight a day, the panel generates 300 Wh of electricity in the best case scenario; which needs to be split between charging the battery and running the server itself.

As for the server, [Kris] chose the Olimex Olinuxino A20 Lime 2 in part because of it being open source hardware, but also because it’s very energy-efficient and includes a AXP209 power management chip. Depending on processor load, the Olimex board draws between 1 and 2.5 watts of power, which combined with charging losses and such means the system can run through two days of cloudy weather before giving up the ghost. A second battery might be added in the future to help improve the run time during low-light conditions, but for now its been working pretty well.

Perhaps the most interesting part of the whole project are the lengths to which the website itself was optimized to keep resource utilization as low as possible. Images are compressed using dithering to greatly reduce their file sizes, and the site eschews modern design in favor of a much less processor intensive static layout. There’s even a battery capacity display integrated into the page through some clever use of CSS. Even if you aren’t looking to set up your own sun worshiping website, there are tips here for building efficient web pages that could absolutely be put to use in other projects.

If you’re interested in solar projects, we’ve got you covered. From an open source charge controller to building DIY photovoltaic panels, there’s plenty of prior art you should find very…illuminating. Please clap.

Solar Power For Chernobyl’s Second Generation Of Electricity

October 7, 2018 by Roger Cheng 40 Comments

When featuring cool hacks repurposing one thing for something else, we prefer to focus on what we could get our hands on and replicate for ourselves. Not this one, though, as nobody else has the misfortune of being responsible for 2,000 square kilometers (772 square miles) of radioactive contaminated land like the government of Ukraine. Trying to make the best of what they have, they’ve just launched a pilot program working to put up solar power farms inside the Chernobyl Exclusion Zone.

This is sure to invite some jokes in the comments section, but the idea has merit. Thirty years of weather has eroded the worst aftermath of the Chernobyl explosion. That area is no longer immediately lethal and people have been making short visits. Spanning from safety inspectors, to scientists, to curious adventurers with questionable judgement making television shows. Supposedly, by following rules on what not to do, it’s possible to keep radiation exposure of a short visit down to the level experienced by frequent fliers. But that’s still too much radiation for long-term stay. That means no homes, office parks, or factories. No agriculture either, as plants and animals grown in the area should not be eaten.

So what’s left? That’s what Ukraine has been struggling with, as it tried to figure out something positive to offset the headaches of monitoring the area.

Well, next to the defunct power plant is the electric distribution infrastructure it used to feed into, and photovoltaic power generation requires little human oversight. Some maintenance will be required, but hopefully someone has worked out how to keep maintenance workers’ cumulative exposure to a minimum. And if this idea pans out, clean renewable energy would start flowing from the site of one of the worst ecological disasters of our era. That makes it a worthwhile hack on a grand scale.

[via Gizmodo]

This Rocket Cookstove Is Hot Stuff!

October 5, 2018 by Jenny List 32 Comments

If you search the web, you will learn that humans began to cook their food with fire a long time ago. Indeed, you might expect that there would be nothing new in the world of flame-based cookery. Fortunately [Bongodrummer] didn’t get that particular memo, because he’s created a rather unusual rocket stove griddle that is capable of cooking a significant quantity of food.

A rocket stove is designed to achieve as efficient use of energy as possible by achieving the most complete burn of high surface area fuel. It features a small combustion area and a chimney with supplementary air feed to ensure that exhaust gasses also burn. This one feeds all those hot gasses directly to the griddle, before taking them away up a pair of flues. As an added bonus there is a dome attachment for a pizza oven, made when a previous project had some left-over building material. Take a look at the comprehensive build video below the break.

Perhaps alarmingly the combustion chamber and chimney are made from a gas cylinder, but the use of a central heating radiator for the griddle is an extremely good idea. A vortex air inlet at the bottom and a secondary air injector further up the chimney complete the unit, making for a worthy replacement for a traditional barbecue.

It’s worth saying, this isn’t the first rocket stove we’ve seen, there was this simple design as well as this very well engineered space heater.

Continue reading “This Rocket Cookstove Is Hot Stuff!” →

Box Forts For Adults: Best Practices And Design Strategies

September 24, 2018 by Lewin Day 33 Comments

Many a grown up can reminisce about building various architectural wonders in their youth. Forts, whether based on boxes or blankets, were the order of the day, and an excellent way to spend a rainy Sunday afternoon.

It just so happens that there is no law against scaling up such activities once one has reached the age of majority. However, to build a structure at this level takes some careful planning and consideration, and that is the purpose of our article here today.

Location, Location, Location

To avoid an awkward conflict, be sure to warn your housemates of impending construction well ahead of time.

The first major consideration when starting your build should be the area in which you wish to do it. Building inside has the advantage of avoiding the weather, however hard floors can lead to sore knees when crawling around. Additionally, you’re a grown up now, so it’s less likely your peers will be impressed to hear you sat inside a box in your living room.

No, if you’re going to do this right, you’ll want to go outside. A nice flat lawn is best, providing soft ground and plenty of space. The challenges of the elements will guide your work – sitting inside your cardboard home feels all the more satisfying when you’re cosy and dry as you listen to the patter of rain on the roof. There’s a real sense of accomplishment when you’ve built something that can survive the harsh outdoors, and besides, the views are better, too. Continue reading “Box Forts For Adults: Best Practices And Design Strategies” →

Talking Garbage Can Keeps Eye On Playground

September 1, 2018 by Tom Nardi 7 Comments

Getting young kids excited about technology and engineering can be a challenge, and getting them interested in the environment isn’t exactly a walk in the park either. So any project that can get them simultaneously engaged in both is a considerable achievement, especially when they can do the work themselves and see how creating something can have a positive impact on their little corner of the world.

[Robert Hart] writes in to tell us about a project that challenged elementary school students to help make sure their peers put trash in its place. The kids came up with some predictably imaginative ideas like a robot to chase down litterers, but as us grown up hackers know all too well, budget and practicality often end up dictating the project’s final form. In the end, they came up with a talking trash can that gives words of encouragement to passerby.

The heart of the system is an Adafruit Audio FX sound board, which has been loaded up with audio clips recorded by the students. The buttons on the front of the can trigger different messages about why it’s important to make sure trash is disposed of properly, and an internal switch allows the can to thank the user for their deposit when the lid has been opened.

A PIR sensor on the front of the can detects when somebody gets close, and plays a message reminding them to make use of the trash cans provided on the playground. It’s not everyday that a child has a garbage can talk to them, so we think this is a fantastic idea for getting a kid’s attention. In keeping with the ecological friendly theme, the whole system is powered by a small solar panel which charges an internal 3.7V LiPo battery with the help of an Adafruit PowerBoost 500.

We’ve seen plenty of unusual projects here at Hackaday, but even for us, a talking garbage can is something of a rarity. Ironically though, we have seen a garbage can which can follow you around, so maybe the kids weren’t so far off with their original idea after all…

Continue reading “Talking Garbage Can Keeps Eye On Playground” →

When Every Last Nanoamp Matters

August 18, 2018 by Brian Benchoff 21 Comments

You can get electricity from just about anything. That old crystal radio kit you built as a kid taught you that, but how about doing something a little more interesting than listening to the local AM station with an earpiece connected to a radiator? That’s what the Electron Bucket is aiming to do. It’s a power harvesting device that grabs electricity from just about anywhere, whether it’s a piece of aluminum foil or a bunch of LEDs.

The basic idea behind the Electron Bucket is to harvest ambient radio waves just like your old crystal radio kit. There’s a voltage doubler, a rectifier, and as a slight twist, a power management circuit that would normally be found in battery-powered electronics.

Of course, this circuit can do more than harvesting electricity from ambient radio waves. By connecting a bunch of LEDs together, it’s possible to send a few Bluetooth packets around. This is pretty impressive — the circuit is using LEDs as solar cells, which normally produce about 50nA of current at 0.5V in direct sunlight. By connecting 12 LEDs in parallel and series, it manages to harvest just enough energy to run a small wireless module. That’s impressive, and an interesting entry to the Power Harvesting Challenge in this year’s Hackaday Prize.

DIY Wind Turbine For Where The Sun Doesn’t Shine

August 14, 2018 by Rich Hawkes 25 Comments

There are plenty of places outside where you may like to have a project requiring electricity that may not get enough sun for solar power to be viable. Perhaps wind power could be used instead? [Greg] has a project to create a platform for using a small wind turbine to generate the power for your projects.

The wind turbine that [Greg] designing is a Savonius-style wind turbine that would put out between 5 and 12 volts. In a Savonius turbine, blades are mounted on a vertical axis allowing for a smaller, less complicated build than traditional horizontal axis wind turbines. The design is named for its inventor, Finnish engineer Sigurd Johannes Savonius.

After doing some research, the design will have a 2:1 height to blade ratio and use three pairs of overlapping curved blades stacked on top of each other, each pair offset by 120 degrees. This design, [Greg] figures, will come within a few percentage points of the efficiency of more exotic blade shapes while making the windmill easy to design and implement. Being half cylinders, the blades can easily be made from existing objects cut in half – pop cans, for example, but there has been some designing the blades in Fusion 360 for 3D printing. The stator board has been designed and the initial prototypes of it and the rotor have arrived, so the testing can now commence.

Once the design is finalized and the prototype working, it’d be interesting to see some projects start showing up using wind power instead of solar power. Take a look at this design for a vertical wind turbine, and this design for a simple, straightforward turbine.