green hacks

771 Articles

How Simple Can A Wind Generator Get?

March 9, 2023 by 12 Comments

As the world has moved towards sustainable energy sources over the last few years, it’s increasingly common to be close to a wind turbine. The huge turbines visible on the horizon from where this is being written are the upper end of the scale though, and along comes [Robert Murray Smith] with the opposite, probably the simplest and smallest wind turbine we’ve seen.

His use of a 3-phase motor from a CD-ROM drive as the generator isn’t particularly unexpected, these motors are ubiquitous and readily generate power when spun up. A simple 3-phase rectifier and a capacitor delivers a DC voltage that while the ready availability of switching converter modules should be relatively easy to turn into something more useful.

The clever part of this hack lies then in the rotor, it’s not the propeller-style bladed affair you might expect. Instead he takes a CD, as it’s the obvious thing to fit on a CD motor, and glues a piece of Tyvek on top of it. This is cut to form four flaps which make a rudimentary but effective turbine when the wind comes from the side. It’s beautifully simple, and we wish we’d thought of it ourselves. The whole thing is in the video below the break, so take a look.

Maybe this won’t solve the green energy requirement on its own, but we’ve shown you far larger fabric turbines in the past.

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A Ground Source Heat Pump From An Air Conditioner

March 7, 2023 by 39 Comments

When it comes to lower-energy home heating, it’s accurate in all senses to say that heat pumps are the new hotness. But unless you happen to work with them professionally, it’s fair to say their inner workings are beyond most of us. Help is at hand though courtesy of [petey53], who made his own ground source heat pump for his Toronto house using a pair of window-mounted air conditioning units.

Continue reading “A Ground Source Heat Pump From An Air Conditioner” →

Screenshot from the presentation, showing the datalogger product image next to the datalogger specs stated. The specs are suspiciously similar to those of a Raspberry Pi 3.

Reclaiming A Pi-Based Solar Datalogger

March 4, 2023 by 7 Comments

There’s quite a few devices on the market that contain a Raspberry Pi as their core, and after becoming a proud owner of a solar roof, [Paolo Bonzini] has found himself with an Entrade ENR-DTLA04DN datalogger which – let’s just say, it had some of the signs, and at FOSDEM 2023, he told us all about it. Installed under the promise of local-only logging, the datalogger gave away its nature with a Raspberry Pi logo-emblazoned power brick, a spec sheet identical to that of a Pi 3, and a MAC address belonging to the Raspberry Pi Foundation. That spec sheet also mentioned a MicroSD card – which eventually died, prompting [Paolo] to take the cover off. He dumped the faulty SD card, then replaced it – and put his own SSH keys on the device while at it.

At this point, Entrade no longer offered devices with local logging, only the option of cloud logging – free, but only for five years, clearly not an option if you like your home cloud-free; the local logging was not flawless either, and thus, the device was worth exploring. A quick peek at the filesystem netted him two large statically-compiled binaries, and strace gave him a way to snoop on RS485 communications between the datalogger and the solar roof-paired inverter. Next, he dug into the binaries, collecting information on how this device did its work. Previously, he found that the device provided an undocumented API over HTTP while connected to his network, and comparing the API’s workings to the data inside the binary netted him some good results – but not enough.

The main binary was identified to be Go code, and [Paolo] shows us a walkthrough on how to reverse-engineer such binaries in radare2, with a small collection of tricks to boot – for instance, grepping the output of strings for GitHub URLs in order to find out the libraries being used. In the end, having reverse-engineered the protocol, he fully rewrote the software, without the annoying bugs of the previous one, and integrated it into his home MQTT network powered by HomeAssistant. As a bonus, he also shows us the datalogger’s main PCB, which turned out to be a peculiar creation – not to spoil the surprise!

We imagine this research isn’t just useful for when you face a similar datalogger’s death, but is also quite handy for those who find themselves at the mercy of the pseudo-free cloud logging plan and would like to opt out. Solar tech seems to be an area where Raspberry Pi boards and proprietary interfaces aren’t uncommon, which is why we see hackers reverse-engineer solar power-related devices – for instance, check out this exploration of a solar inverter’s proprietary protocol to get data out of it, or reverse-engineering an end-of-life decommissioned but perfectly healthy solar inverter’s software to get the service menu password.

AGES Of Renewable Energy Storage

March 3, 2023 by 26 Comments

As society transitions toward renewable energy sources, energy storage inevitably comes to mind. Researchers at the University of Illinois at Urbana-Champaign have found one way to store renewable energy that re-purposes existing fossil fuel infrastructure.

While geothermal electricity generation shows a lot of promise, it’s currently limited to a select few areas where hot rock is close to the Earth’s surface. Advanced Geothermal Energy Storage (AGES) stores energy underground as heat and recovers it later, even in places without high subsurface temperatures. For this study, the researchers located an old oil well and instrumented it with “flow meters, fiber optic
distributed temperature sensing (DTS) cable, surface pressure and temperature gauges, and downhole pressure and temperature gauges to monitor the thermal and hydraulic changes during the injection test.”

This field study found that AGES system efficiency could be as high as 82% and yield an “economically viable” levelized cost of electricity (LCOE) of $0.138/kWh. Using existing deep hole infrastructure speeds up site selection and deployment of AGES when compared to developing on an undisturbed location, making this a very interesting way to deploy grid-scale storage rapidly.

We’ve covered reusing fossil fuel infrastructure before as well as challenges and unusual solutions to the energy transition if you’re looking for more about what might be on a future smart grid.

A grey car sits in the background out of focus, its front facing the camera. It sits over an asphalt roadway with a metal rail extending from the foreground to behind the car in the distance. The rail has a two parallel slots and screws surrounding the slots running down the rail.

What Happened To Sweden’s Slot Car EV Road?

March 1, 2023 by 60 Comments

Many EVs can charge 80% of their battery in a matter of minutes, but for some applications range anxiety and charge time are still a concern. One possible solution is an embedded electrical rail in the road like the [eRoadArlanda] that Sweden unveiled in 2016.

Overhead electrical wires like those used in trolleys have been around since the 1800s, and there have been some tests with inductive coils in the roadway, but the 2 km [eRoadArlanda] takes the concept of the slot car to the next level. The top of the rail is grounded while the live conductor is kept well underground beneath the two parallel slots. Power is only delivered when a vehicle passes over the rail with a retractable contactor, reducing danger for pedestrians, animals, and other vehicles.

One of the big advantages of this technology being in the road bed is that both passenger and commercial vehicles could use it unlike an overhead wire system that would require some seriously tall pantographs for your family car. Testing over several Swedish winters shows that the system can shed snow and ice as well as rain and other road debris.

Unfortunately, the project’s website has gone dark, and the project manager didn’t respond when we reached out for comment. If there are any readers in Sweden with an update, let us know in the comments!

We’ve covered both overhead wire and embedded inductive coil power systems here before if you’re interested in EV driving with (virtually) unlimited range.

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Repurposing Old Smartphones: When Reusing Makes More Sense Than Recycling

February 28, 2023 by 89 Comments

When looking at the specifications of smartphones that have been released over the past years, it’s remarkable to see how aspects like CPU cores, clockspeeds and GPU performance have improved during this time, with even new budget smartphones offering a lot of computing power, as well as a smattering of sensors. Perhaps even more remarkable is that of the approximately 1.5 billion smartphones sold each year, many will be discarded again after a mere two years of use. This seems rather wasteful, and a recent paper by Jennifer Switzer and colleagues proposes that a so-called Computational Carbon Intensity (CCI) metric should be used to determine when it makes more sense to recycle a device than to keep using it.

What complicates the decision of when it makes more sense to reuse than recycle is that there are many ways to define when a device is no longer ‘fit for purpose’. It could be argued that the average smartphone is still more than good enough after two years to be continued as a smartphone for another few years at least, or at least until the manufacturer stops supplying updates. Beyond the use as a smartphone, they’re still devices with a screen, WiFi connection and a capable processor, which should make it suitable for a myriad of roles.

Unfortunately, as we have seen with the disaster that was Samsung’s ‘upcycling’ concept a few years ago, or Google’s defunct Project Ara, as promising as the whole idea of ‘reuse, upcycle, recycle’ sounds, establishing an industry standard here is frustratingly complicated. Worse, over the years smartphones have become ever more sealed-up, glued-together devices that complicate the ‘reuse’ narrative.

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Low Power Challenge: Keep Plants Green And Clean With E-Paper Smart Tags

February 25, 2023 by 7 Comments

There are plenty of reasons to devote oneself to the care of houseplants — after all, a room full of bright, glossy-leaved plants can be a joy to behold, and that’s not even one of the more tangible benefits they bring. But as any green thumb knows, there’s a fine line between a healthy, vibrant plant and one that’s soon to give up the ghost.

If your thumb tends less toward green and more toward the brown and crusty side of things, something like [Jon]’s Smart Plant system might be just the thing for you. These low-power plant tags are built around increasingly ubiquitous e-Paper displays, like the kind you might find in a retail shelf price tag system. The current version of [Jon]’s tags uses a Waveshare 2.9″ tricolor display and a PCB with capacitive probes that stick into the plant’s soil. An ESP32-S lives on the top section of the PCB, along with a 1,000 mAh LiPo pack that’s charged off USB-C. The design includes an optional solar panel for keeping the battery topped off, which may or may not help depending on the plant’s place in your personal jungle.

In addition to the soil moisture sensor, the Smart Tag has an ambient temperature and humidity sensor and a light sensor — everything to keep your plant happy. The power-hungry sensors are only powered on when the Smart Tag pops out of deep sleep; this gives and estimated five to six weeks runtime between charges, without solar charging of course. The e-Paper display shows custom graphics of the plant’s current environmental state, and the same data is also available via Home Assistant thanks to the ESPHome firmware.

These are nice-looking plant tags that can really pull a lot of weight in keeping plants healthy. Check out the other offerings in our Low Power Challenge Contest, and maybe get an entry together yourself.

2023 Hackaday.io Low-Power Challenge