green hacks

796 Articles

Dealing With Invasive Species Through Robotics

September 24, 2019 by 23 Comments

Throughout its history, humankind’s travels have often brought unwelcome guests along for the ride, and sometimes introduced species into a new environment for a variety of reasons. These so-called invasive species are all too often responsible for widespread devastation in ecosystems, wiping out entire species and disrupting the natural balance. Now researchers are testing the use of robots for population control of these invasive species.

The mosquitofish is the target of current research by NYU Tandon School of Engineering and the University of Western Australia. Originally from parts of the US and Mexico, it was introduced elsewhere for mosquito control, including in Australia. There it has become a massive problem, destroying native species that used to eat mosquitoes. As a result the mosquito problem has actually worsened.

As the main issue with these invasive species is that they do not have any natural predators that might control their numbers, the researchers created robots which mimic the look and motion of natural predators. In the case of the mosquitofish the largemouth bass is its primary predator. The theory was that by exposing the mosquitofish to something that looks and moves just like one of these predator fish, they would exhibit the same kind of stress response.

So far laboratory tests under controlled condition have confirmed these expectations, with the mosquitofish displaying clear signs of stress upon exposure to the robotic largemouth bass. Even better, they displayed decreasing weight and were found to avoid potentially dangerous areas, indicating that instead of focusing on foraging, they were in survival mode. This should limit their environmental impact, including their ability to procreate.

Who knows, before long the surface waters of Australia may be home to the first robotic species of fish.

(Thanks, [Qes])

3D Print A Complete Wind Generator

September 19, 2019 by 22 Comments

For many of us our landscapes are dotted with wind turbines, the vast majority of which are horizontally aligned as if they were giant aircraft propellers. A much rarer sight is the vertical wind turbine, which remains a staple of the wind power experimenter. [Troy] and his brother have posted a video showing a small wind 3D printed vertical turbine, which unusually includes an alternator made from scratch as well as the rotor itself.

The machine adopts a Savonius rotor design with three scoops, which offers simplicity and high torque at a lower rotational speed than some of the alternatives. The scoops are assembled from a number of 3D-printed sections, and directly drive the generator which uses a large number of coils on a stator encircled by a rotor containing an array of magnets. A simple rectifier and three-terminal regulator produces a 5-volt output.

Sadly there was not enough wind to give it a decent test for the video, but they demonstrate it with a very large fan standing in. We like the alternator design but we’d be interested to see how the sectional rotors hold up in outdoor conditions, and perhaps that regulator could benefit from a switch-mode component. If you fancy a go he says he’ll release the files as open source if there’s enough interest. We’re interested [Troy], please do!

Many wind turbines have passed through these pages over the years, and for contrast here’s a horizontal 3D printed example.

Continue reading “3D Print A Complete Wind Generator” →

Solar System Wars: Walmart Versus Tesla

September 19, 2019 by 61 Comments

It seems like hardly a day goes by that doesn’t see some news story splashed across our feeds that has something to do with Elon Musk and one or another of his myriad companies. The news is often spectacular and the coverage deservedly laudatory, as when Space X nails another double landing of its boosters after a successful trip to space. But all too often, it’s Elon’s baby Tesla that makes headlines, and usually of the kind that gives media relations people ulcers.

The PR team on the automotive side of Tesla can take a bit of a breather now, though. This time it’s Elon’s solar power venture, Tesla Energy Operations, that’s taking the heat. Literally — they’ve been sued by Walmart for rooftop solar installations that have burst into flames atop several of the retail giant’s stores. While thankfully no lives have been lost and no major injuries were reported, Walmart is understandably miffed at the turn of events, leading to the litigation.

Walmart isn’t alone in their exposure to potential Tesla solar problems, so it’s worth a look to see what exactly happened with these installations, why they failed, and what we as hackers can learn from the situation. As we’ll see, it all boils down to taking electrical work very seriously and adhering to standards designed to keep everyone safe, even when they just seem like a nuisance.

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Using The Electricity Grid In Cities As A Source Of Heat

September 15, 2019 by 32 Comments

In the process of finding new, low-carbon ways to provide our homes with heat and electricity, it is that one might consider sources that never before came to mind. In London such a source that has been examined by researchers and an electricity network operator are the 2.5 meter wide tunnels that run for many kilometers underneath the city. In each of them are many more kilometers worth of electricity distribution cables, each of which produces so much heat from electric resistance that active cooling is required.

Currently, every 1.8 kilometers there are shafts that lead to the surface, through which cold surface air is brought in and the warm tunnel air is exhausted into the air. The study by London South Bank University researchers and UK Power Networks looked at using this heat directly for heating local houses, replacing the use of gas boilers. This is in effect similar to heating with waste heat from industrial processes, but with noticeable differences.

The thermal power available from each 1.8 kilometer section of tunnel differs between 100 – 460 kW by installing equipment at the top of the shafts. With London looking at using heat from the London Underground for heating in a similar fashion, it would be fascinating to see whether the combined heat from both underground sources could provide the city with a sizeable source of low-carbon heat, while increasing creature comfort.

Building A Full-Fat Air Quality Monitor

September 3, 2019 by 13 Comments

Over the years many people have made an air quality monitor station, usually of some configuration which measures particulates (PM2.5 & PM10). Some will also measure ozone (O3), but very few will meet the requirements that will allow one to calculate the Air Quality Index (AQI) as used by the EPA and other organizations. [Ryan Kinnett]’s project is one of those AQI-capable stations.

The AQI requires the measurement of the aforementioned PM2.5 (µg/m3), PM10 (µg/m3) and O3 (ppb), but also CO (ppm), SO2 (ppb) and NO2 (ppb), all of which has to be done with specific sensitivities and tolerances. This means getting sensitive enough sensors that are also calibrated. [Ryan] found a company called Spec Sensors who sell sensors which are pretty much perfect for this goal.

Using Spec Sensor’s Ultra-Low Power Sensor Modules (ULPSM) for ozone, nitrogen-dioxide, carbon monoxide and sulfur dioxide, a BME280 for air temperature, pressure and relative humidity, as well as a Plantower PMS5003 laser particle counter and an ADS1115 ADC, a package was created that fit nicely alongside an ESP8266-based NodeMCU board, making for a convenient way to read out these sensors. The total one-off BOM cost is about $250.

The resulting data can be read out and the AQI calculated from them, giving the desired results. Originally [Ryan] had planned to take this sensor package along for a ride around Los Angeles, to get more AQI data than the EPA currently provides, but with the time it takes for the sensors to stabilize and average readings (1 hour) it would take a very long time to get the readings across a large area.

Ideally many of such nodes should be installed in the area, but this would be fairly costly, which raises for [Ryan] the question of how one could take this to the level of the Air Quality Citizen Science project in the LA area. Please leave your thoughts and any tips in the comments.

Automate Sorting Your Trash With Some Healthy Machine Learning

September 1, 2019 by 10 Comments

Sorting trash into the right categories is pretty much a daily bother. Who hasn’t stood there in front of the two, three, five or more bins (depending on your area and country), pondering which bin it should go into? [Alvaro Ferrán Cifuentes]’s SeparAItor project is a proof of concept robot that uses a robotic sorting tray and a camera setup that aims to identify and sort trash that is put into the sorting tray.

The hardware consists of a sorting tray mounted to the top of a Bluetooth-connected pan and tilt platform. The platform communicates with the rest of the system, which uses a camera and OpenCV to obtain the image data, and a Keras-based back-end which implements a deep learning neural network in Python.

Training of the system was performed by using self-made photos of the items that would need to be sorted as these would most closely match real-life conditions. After getting good enough recognition results, the system was put together, with a motion detection feature added to respond when a new item was tossed into the tray. The system will then attempt to identify the item, categorize it, and instruct the platform to rotate to the correct orientation before tilting and dropping it into the appropriate bin. See the embedded video after the break for the system in action.

Believe it or not, this isn’t the first trash-sorting robot to grace the pages of Hackaday. Potentially concepts like these, that rely on automation and machine vision, could one day be deployed on a large scale to help reduce how much recyclable material end up in landfills. Continue reading “Automate Sorting Your Trash With Some Healthy Machine Learning” →

Human-Powered Henhouse Keeps Chickens On The Job

September 1, 2019 by 37 Comments

While it’s not exactly in the same vein as other projects around here, like restoring vintage video game systems or tricking an ESP32 to output VGA, keeping chickens can also be a rewarding hobby. They make decent pets and can also provide you with eggs. You can also keep them on a surprisingly small amount of land, but if you have a larger farm you can use them to help condition the soil all over your property. For that you’ll need a mobile henhouse, and as [AtomicZombie] shows, they don’t all have to be towed by a tractor.

This henhouse is human-powered, meaning any regular human can lift it up and scoot it around to different areas without help from heavy equipment. It uses a set of bicycle wheels which rotate around to lift up the frame of the house. A steering wheel in the back allows it to be guided anywhere and then set down. It also has anti-digging protection, which is a must-have for any henhouse to keep the foxes out.

We like this one for its simplicity and ease-of-use. Not needing a tractor on a small farm can be a major cost savings, but if you really need one, [AtomicZombie] also designed a robust all-electric tractor-like device that we featured a little while back.

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