2023 Hackaday Prize: A Reinvented Solar Tracker

August 9, 2023 by Matthew Carlson 35 Comments

It probably goes without saying that solar panels need to be pointed at the sun for optimal performance. The tricky bit is that the sun has a funny habit of moving on you. For those with a solar panel on their balcony or garden, mysoltrk tracks the sun to get the most out of a small solar panel.

[Fulvio] built the tracker to be solid, low cost, and sturdy enough to survive outdoors, which is quite a tall order. Low cost meant WiFi and GPS were out. The first challenge was low-cost linear actuators that were 3D printed with a mechanism to lock the shaft. An N20 6 volt 30 RPM geared motor formed the heart of the actuator. Four photo-resistors inside a printed viewfinder detect where the sun is, allowing the system to steer the array to get equal values on all the sensors. An Arduino Nano was chosen as it was low power, low cost, and easy to modify. A L298N h-bridge drives the motors, and a shunt is used instead of limit switches to reduce costs further.

There are a few other clever tricks. A voltage divider reads the power coming off the panel so the circuit doesn’t brown out trying to move the actuators. The load can also be switched off via an IRL540n. As of the time of writing, only the earlier versions of the code are up on GitHub, as [Fulvio] is still working on refining the tracking algorithm. But the actuators work wonderfully. We love the ingenuity and focus on low cost, which probably explains why mysoltrk was selected as a finalist in the 2023 Hackaday Prize Green Hacks challenge.

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Clipper Windpower: Solutions In Search Of Problems

August 2, 2023 by Bryan Cockfield 67 Comments

The first modern wind turbines designed for bulk electricity generation came online gradually throughout the 80s and early 90s. By today’s standards these turbines are barely recognizable. They were small, had low power ratings often in the range of tens to hundreds of kilowatts, and had tiny blades that had to rotate extremely quickly.

When comparing one of these tiny machines next to a modern turbine with a power rating of 10 or more megawatts with blades with lengths on the order of a hundred meters, one might wonder if there is anything in common at all. In fact, plenty of turbines across the decades share fundamental similarities including a three-blade design, a fairly simple gearbox, and a single electric generator. While more modern turbines are increasingly using direct-drive systems that eliminate the need for a gearbox and the maintenance associated with them, in the early 2000s an American wind turbine manufacturer named Clipper Windpower went in the opposite direction, manufacturing wind turbines with an elaborate, expensive, and heavy gearbox that supported four generators in each turbine. This ended up sealing the company’s fate only a few years after the turbines were delivered to wind farms.

Some history: the largest terrestrial wind turbines were approaching the neighborhood of 2 megawatts, but some manufacturers were getting to these milestones essentially by slapping on larger blades and generators to existing designs rather than re-designing their turbines from the ground up to host these larger components. This was leading to diminishing returns, as well as an increased amount of mechanical issues in the turbines themselves, and it was only a matter of time before the existing designs wouldn’t support this trend further. Besides increased weight and other mechanical stresses on the structure itself, another major concern was finding (and paying for) cranes with enough capacity to hoist these larger components to ever-increasing heights, especially in the remote locations that wind farms are typically located. And cranes aren’t needed just for construction; they are also used whenever a large component like a generator or blade needs to be repaired or replaced. Continue reading “Clipper Windpower: Solutions In Search Of Problems” →

MIT Cracks The Concrete Capacitor

August 1, 2023 by Jenny List 60 Comments

It’s a story we’ve heard so many times over the years: breathless reporting of a new scientific breakthrough that will deliver limitless power, energy storage, or whichever other of humanity’s problems needs solving today. Sadly, they so often fail to make the jump into our daily lives because the reporting glosses over some exotic material that costs a fortune or because there’s a huge issue elsewhere in their makeup. There’s a story from MIT that might just be the real thing, though, as a team from that university claim to have made a viable supercapacitor from materials as simple as cement, carbon black, and a salt solution. Continue reading “MIT Cracks The Concrete Capacitor” →

Harvesting Mechanical Energy From Falling Rain

July 30, 2023 by Bryan Cockfield 40 Comments

Collecting energy from various small mechanical processes has always been something that’s been technically possible, but never done on a large scale due to issues with cost and scalability. It’s much easier to generate electricity in bulk via traditional methods, whether that’s with fossil fuels or other proven processes like solar panels. That might be about to change, though, as a breakthrough that researchers at Georgia Tech found allows for the direct harvesting of mechanical energy at a rate much higher than previous techniques allowed.

The method takes advantage of the triboelectric effect, which is a process by which electric charge is transferred when two objects strike or slide past one another. While this effect has been known for some time, it has only been through the advancements of modern materials science that it can be put to efficient use at generating energy, creating voltages many thousands of times higher than previous materials allowed. Another barrier they needed to overcome was how to string together lots of small generators like this together. A new method that allows the cells to function semi-independently reduces the coupling capacitance, allowing larger arrays to be built.

The hope is for all of these improvements to be combined into a system which could do things like augment existing solar panels, allowing them to additionally gather energy from falling rain drops. We’d expect that the cost of this technology would need to come down considerably in order to be cost-competitive, and be able to scale from a manufacturing point-of-view before we’d see much of this in the real world, but for now at least the research seems fairly promising. But if you’re looking for something you can theoretically use right now, there are all kinds of other ways to generate energy from fairly mundane daily activities.

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This Month’s World’s Largest Wind Turbine Goes Operational

July 26, 2023 by Chris Lott 56 Comments

A new wind turbine installed in the Taiwan Strait went online last week, as part of the Fujian offshore wind farm project by the China Three Gorges Corporation (CTG). The system is the MySE 16-260, designed by the Ming Yang Wind Power Group, one of the leading manufacturers of wind turbines in the world. The numbers are staggering, the 16MW generator is projected to provide 66 GWh (gigawatt-hours) to the power grid annually. And this is a hefty installation, with a 260 m rotor diameter ( three each 123 m blades ) sitting atop a 152 m tower. The location is both a blessing and a curse, being an area of the Pacific that experiences Beaufort level 7 winds ( near gale, whole trees in motion ) for more than 200 days per year. Understandably, the tower and support structures are beefy, designed to survive sustained winds of 287 km/h.

This 16 MW installation surpasses the previous record holder, announced this January — the Vestas V236-15.0MW turbine with 115.5 m blades, located in Denmark’s Østerild Wind Turbine Test Center. But wait … Ming Yang also announced in January their new 18 MW turbine with 140 m long blades.

We imagine that there will eventually be a natural plateau, where the cost of the next humongous installation approaches or exceeds that of multiple smaller ones. Or will these multi-megawatt turbine systems just keep leapfrogging each other, year after year? Let us know your thoughts in the comments below.

Mapping The Depths With An Autonomous Solar Boat

July 23, 2023 by Tom Nardi 17 Comments

Ever look out at a pond, stream, or river, and wonder how deep it is? For large bodies of water that are considered navigable, it’s easy enough to pull up a chart and find out. But what if there’s no public data for the area you’re interested in?

Well, you could spend all day on a little boat taking depth readings and making your own chart, but if you’re anything like [Clay] you could build a solar-powered autonomous robot to do it for you. He’s been working on the boat, which he calls Gumption Trap, for the better part of a year now. If we had to guess, we’d say the experience of designing and building it has ended up being a bit more interesting to him than the actual depth of the water — but that’s fine by us.

The design of the boat is surprisingly economical, as far as marine designs go. Two capped four-inch PVC pipes are used as pontoons, and 3D printed brackets attach those to an aluminum extrusion frame that holds the electronics and solar panel high above the water. This arrangement provides an exceptionally stable platform that would be all but impossible to flip under normal circumstances.

Around the back of the craft, there’s a pair of massive 3D printed thrusters, complete with some remarkably chunky printed propellers. The lack of rudders keeps things simple, with differential thrust between the two motors enough to keep the Gumption pointed in the right direction.

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A wooden robot with a large fresnel lens in a sunny garden

Gardening Robot Uses Sunlight To Incinerate Weeds

June 30, 2023 by Robin Kearey 36 Comments

Removing weeds is a chore few gardeners enjoy, as it typically involves long sessions of kneeling in the dirt and digging around for anything you don’t remember planting. Herbicides also work, but spraying poison all over your garden comes with its own problems. Luckily, there’s now a third option: [NathanBuildsDIY] designed and built a robot to help him get rid of unwanted plants without getting his hands dirty.

Constructed mostly from scrap pieces of wood and riding on a pair of old bicycle wheels, the robot has a pretty low-tech look to it. But it is in fact a very advanced piece of engineering that uses multiple sensors and actuators while running on a sophisticated software platform. The heart of the system is a Raspberry Pi, which drives a pair of DC motors to move the whole system along [Nathan]’s garden while scanning the ground below through a camera.

The Pi runs the camera’s pictures through a TensorFlow Lite model that can identify weeds. [Nathan] built this model himself by taking hundreds of pictures of his garden and manually sorting them into categories like “soil”, “plant” and “weed”. Once a weed has been detected, the robot proceeds to destroy it by concentrating sunlight onto it through a large Fresnel lens. The lens is mounted in a frame that can be moved in three dimensions through a set of servos. A movable lens cover turns the incinerator beam on or off.

Sunlight is focused onto the weed through a simple but clever two-step procedure. First, the rough position of the lens relative to the sun is adjusted with the help of a sun tracker made from four light sensors arranged around a cross-shaped cardboard structure. Then, the shadow cast by the lens cover onto the ground is observed by the Pi’s camera and the lens is focused by adjusting its position in such a way that the image formed by four holes in the lens cover ends up right on top of the target.

Once the focus is correct, the lens cover is removed and the weed is burned to a crisp by the concentrated sunlight. It’s pretty neat to see how well this works, although [Nathan] recommends you keep an eye on the robot while it’s working and don’t let it near any flammable materials. He describes the build process in full detail in his video (embedded below), hopefully enabling other gardeners to make their own, improved weed burner robots. Agricultural engineers have long been working on automatic weed removal, often using similar machine vision systems with various extermination methods like lasers or flamethrowers.

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