If you’ve been to downtown San Francisco lately, you might have noticed something odd about the decorative trees in the city: they’re now growing fruit. This is thanks to a group of people called the Guerrilla Grafters who are covertly grafting fruit-bearing twigs to city tress which would otherwise be fruitless. Their goal is to create a delicious, free source of food for those living in urban environments.
Biology-related hacks aren’t something we see every day, but they’re out there. For those unfamiliar with grafting, it’s a process that involves taking the flowering, fruiting, or otherwise leafy section of one plant (a “scion”) and attaching them to the vascular structure of another plant that has an already-established root system (the “stock”). The Guerrilla Grafters are performing this process semi-covertly and haven’t had any run-ins with city officials yet, largely due to lack of funding on the city’s part to maintain the trees in the first place.
This hack doesn’t stop at the biological level, though. The Grafters have to keep detailed records of which trees the scions came from, when the grafts were done, and what characteristics the stock trees have. To keep track of everything they’ve started using RFID tags. This is an elegant solution that can be small and inconspicuous, and is a reliable way to keep track of all of one’s “inventory” of trees and grafts.
It’s great to see a grassroots movement like this take off, especially when it seems like city resources are stretched so thin that the trees may have been neglected anyway. Be sure to check out their site if you’re interested in trying a graft yourself. If you’re feeling really adventurous, you can take this process to the extreme.
Irrigation is a fairly crude practice. Sure, there are timers, and rain sensors, but all in all we’re basically dumping water on the ground and guessing at the right amount. [Reinier van der Lee] wanted a better way to ensure the plants in his vineyard are getting the right amount of water. And this is Goldilocks’ version of “right”, not too little but also not too much. Southern California is in an extreme/exceptional drought. Water costs a lot of money, but it is also scarce and conservation has a wider impact than merely the bottom line.
His solution is the Vinduino project. It’s a set of moisture sensors that work in conjunction with a handheld device to measure the effect of irrigation. Multiple moisture sensors are buried at different depths: near the surface, at root level, and below root level. This lets you know when the water is getting to the root system, and when it has penetrated further than needed. The project was recognized as the Best Product in the 2015 Hackaday Prize, and [Reinier] presented the project during his talk at the Hackaday SuperConference. Check out the video of that talk below, and join us after the break for a look at the development of this impressive product.
If you’re looking for the future of humanity, look no further than the first plasma generated in the Wendelstein 7-X Stellerator at the Max Planck Institute for Plasma Physics. It turned on for the first time yesterday, and while this isn’t the first fusion power plant, nor will it ever be, it is a preview of what may become the invention that will save humanity.
For a very long time, it was believed the only way to turn isotopes of hydrogen into helium for the efficient recovery of power was the Tokamak. This device, basically a hollow torus lined with coils of wire, compresses plasma into a thin circular string. With the right pressures and temperatures, this plasma will transmute the elements and produce power.
Tokamaks have not seen much success, though, and this is a consequence of two key problems with the Tokamak design. First, we’ve been building them too small, although the ITER reactor currently being built in southern France may be an exception. ITER should be able to produce more energy than is used to initiate fusion after it comes online in the 2020s. Tokamaks also have another problem: they cannot operate continuously without a lot of extraneous equipment. While the Wendelstein 7-X Stellerator is too small to produce a net excess of power, it will demonstrate continuous operation of a fusion device. [Elliot Williams] wrote a great explanation of this Stellerator last month which is well worth a look.
While this Stellerator is just a testbed and will never be used to generate power, it is by no means the only other possible means of creating a sun on Earth. The Polywell – a device that fuses hydrogen inside a containment vessel made of electromagnets arranged like the faces of a cube – is getting funding from the US Navy. Additionally, Lockheed Martin’s Skunk Works claims they can put a 100 Megawatt fusion reactor on the back of a truck within a few years.
The creation of a fusion power plant will be the most important invention of all time, and will earn the researchers behind it the Nobel prize in physics and peace. While the Wendelstein 7-X Stellarator is not the first fusion power plant, it might be a step in the right direction.
We’ll stipulate that “wireless” is a bit of a stretch. Creator [David Schneider] chose to split the system into two parts – a magnetometer and an Arduino to sense impulses from the water company meter, and a Raspberry Pi to serve the web interface. The water meter is at the street rather than in his house, so the sensor is wired to the Pi with some telephone cable. But from there the system is wireless.
[David] goes into some good detail on the sensing problem he faced, which relies on detecting the varying magnetic field due to the spinny-bits inside the flowmeter and cleaning up the signal with the Arduino; he also addresses aliasing errors that occur when flow rate approaches the sampling rate of the magnetometer.
We like the fact that there’s a lot of potential to leverage this technique to monitor other processes with rotating magnetic fields. And like this optically coupled gas-meter monitor, it’s not invasive of the utility’s equipment either, which is a plus.
The 80 acres of hills and valleys are called the Buitenschot ‘land art park’ and supposedly reduce noise in the nearby neighborhood by around 50%. They work by sending the reflections in random directions that would otherwise skip off of the ground, just like anti-echo baffles in a sound studio. A nice touch for the local residents, they also contain jogging trails.
Beauty is in the eye of the beholder, of course. Unfortunately, as the Smithsonian notes, nobody is beholding it. Because Buitenschot aims to diffuse the takeoff noise coming out of the rear of the planes, they are always flying away from it; passengers don’t get to see it from the air.
“In the future, we’ll be generating a significant fraction of our electricity from harnessing the waves!” People have been saying this for decades, and wave-generated electricity is not a significant fraction of an ant’s poop. It’d be fantastic if this could change.
If you believe the owners of Oscilla Power, the main failing of traditional wave-power generators is that they’ve got too many moving parts. Literally. Metal mechanical parts and their seals and so on are beaten down by sun and salt and surf over time, so it’s expensive to maintain most of the generator designs, and they’re just not worth it.
Magnetostriction is the property that magnetic materials can shrink or expand just a little bit when put in a magnetic field. The Villari effect (which sounds much cooler than “inverse magnetostriction”) is the opposite: magnetic materials get more or less magnetic when they’re squeezed.
So to make a generator, you put two permanent magnets on either end, and wind coils around magnetostrictive metal bars that are inside the field of the permanent magnets. Squeeze and stretch the bars repeatedly and the net magnetic field inside the coils changes, and you’re generating electricity. Who knew?
Right now, according to The Economist Magazine’s writeup on Oscilla, the price per watt isn’t quite competitive with other renewable energy sources, but it’s looking close. With some more research, maybe we’ll be getting some of our renewable energy from squeezing ferrous bars.