Lettuce For Life!

If you take a head of romaine lettuce and eat all but the bottom 25mm/1inch, then place the cut-off stem in a bowl of water and leave it in the sun, something surprising happens. The lettuce slowly regrows. Give it a few nutrients and pay close attention to optimum growing conditions, and it regrows rather well.

lettuce-for-life-hydroponic-systemThis phenomenon caught the attention of [Evandromiami], who developed a home-made deep water culture hydroponic system to optimise his lettuce yield. The lettuce grows atop a plastic bucket of water under full spectrum grow lights, while an Intel Curie based Arduino 101 monitors and regulates light levels, humidity, temperature, water level, and pH. The system communicates with him via Bluetooth to allow him to tweak settings as well as to give him the data he needs should any intervention be required. All the electronics are neatly contained inside a mains power strip, and the entire hydroponic lettuce farm lives inside a closet.

He does admit that he’s still refining the system to the point at which it delivers significant yields of edible lettuce, but it shows promise and he’s also experimenting with tomatoes.

Our community have a continuing fascination with hydroponic culture judging by the number of projects we’ve seen over the years. This isn’t the first salad system, and we’ve followed urban farming before, but it’s winter strawberries that really catch the attention.

Hackaday Prize Entry: Dave Thomas’ Desert Dryer

It seemed utter madness — people living in hot desert climates paying to heat air. At least it seemed that way to [David Thomas] before he modified his tumble dryer to take advantage of Arizona’s arid environment.

Hanging the wash out to dry is a time-honored solution, and should be a no-brainer in the desert. But hanging the wash takes a lot of human effort, your laundry comes back stiff, and if there’s a risk of dust storms ruining your laundry, we can see why people run the dryer indoors. But there’s no reason to waste further energy heating up your air-conditioned interior air when hot air is plentiful just a few meters away.

[David]’s modification includes removing the gas heating components of the dryer and adding an in-line filter. He explains it all in a series of videos, which at least for his model, leave no screw unturned. It’s not an expensive modification either, consisting mostly of rigid dryer hose and copious amounts of aluminum duct tape. He mentions the small fire that resulted from failing to remove the gas igniter, so consider yourself warned. The intake filter and box were originally intended for a house air-conditioning system, and required only minimal modifications.

This is a great build, being both cheap and easy to implement as well as being environmentally friendly without requiring a drastic change to [David]’s lifestyle. It makes us wish we had a similar endless supply of hot air.

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Scratch-Fabricated Plastic Gobbling Shredder Brings Recycling Home

[Jason Knight], an intern at FabLab RUC, has worked hard for 9 months to make a sheet plastics shredder for HDPE and LDPE from things like plastic bags, bubble wrap and air cushion packaging with the goal of recycling the shredded plastic. Why shred these things? When broken down to smaller pieces they can be melted in a consumer grade oven (like where you cook your frozen pizzas) then molded into new objects or extruded into 3D printing filament.

We especially like his big homemade 1.1 inch (30mm) thick wooden gears, for transferring the rotation from the motor to the cutting shafts while giving a step up in torque. As you can see in the video below, the gears definitely add an extra look of power to the machine.

The blades are the shape you most often see in shredders, gear-like disks side-by-side with teeth cut from them that pull the plastic in while shredding it (in contrast to this lower-throughput experimental DIY shredder made with two steel pipes). [Jason’s] multiple teeth are a bit of work to fabricate — not only were all the teeth milled from sheet metal but they then had to be individually sanded to remove burrs from the edges. It was worth it, as this has no problem chewing waste plastics to pieces.

Shredders can be dangerous machines for wandering fingers so [Jason] added a few safety features. Those include a drawer that you open to insert your plastic into the shredding area and a guard that completely surrounds the gears. And both features include transparent plastic areas so that you can still watch the impressive working parts in action.

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Waste Not, No Lights

Alchemists tried in vain to transmute lead into gold. What if you could turn waste products into energy? That’s what [chemicum] did in a recent video–he and some friends built microbial fuel cells that convert excrement into electricity (you can see the video, below).

The video doesn’t give you all the details of the build, but it seems easy enough. You need some stainless steel mesh, some activated charcoal, some epoxy, plastic containers, and some assorted metal plates and hardware. Of course, you also need excrement and–if the video is any indication–some clothespins to clamp your nose shut as you work.

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The Coming Wide-Spread Use of Drones in Agriculture

Whether you call them UAVs (Unmanned Aerial Vehicles), UAS (Unmanned Aerial System), Drones, or something less polite – people are more familiar than ever with them. We’ll call them drones, and we’re not talking about the remote-controlled toy kind – we’re talking about the flying robot kind. They have sensors (GPS and more), can be given a Flight Plan (instructions on where to go), and can follow that plan autonomously while carrying out other instructions – no human pilot required. Many high-end tractors are already in service with this kind of automation and we’ve even seen automated harvesting assistance. But flying drones are small and they don’t plant seeds or pull weeds, so what exactly do they have to do with agriculture?

There are certain things that drones are very good at, and there are things in agriculture that are important but troublesome to do or get. Some of these things overlap, and in those spaces is where a budding industry has arisen.

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Energy Monitor Optically Couples to Smart Meter

Hackers love to monitor things. Whether it’s the outside temperature or the energy used to take a shower, building a sensor and displaying a real-time graph of the data is hacker heaven. But the most interesting graphs comes from monitoring overall power use, and that’s where this optically coupled smart-meter monitor comes in.

[Michel]’s meter reader is pretty straightforward. His smart wattmeter is equipped with an IR LED that pips for every watt-hour consumed, so optical coupling was a natural approach. The pulse itself is only 10 ms wide, so he built a pulse stretcher to condition the pulse for a PIC microcontroller. The PIC also reads the outside temperature with a DS18B20 and feeds everything to the central power monitor, with an LCD display and a classic Simpson meter to display current power usage. The central monitor sends the power and temperature data to Thingspeak, along with data from [Michel]’s wood-stove monitor and a yet-to-be-implemented water heater monitor.

[Michel] is building out an impressive suite of energy and environmental monitors for his Quebec base of operations. We’re looking forward to seeing how he monitors that water heater, and to see what other ideas he comes up with.

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Are Powdered Metal Fuels Just a Flash in the Pan?

It’s no secret that fossil fuels are quickly becoming extinct. As technology charges ever forward, they are disappearing faster and faster. Many of our current dependencies on fossil fuels are associated with high-energy applications like transportation. Since it’s unlikely that global transportation will ever be in decline for any reason other than fuel shortage itself, it’s imperative that we find something that can replicate the high energy density of fossil fuels. Either that, or go back to the drawing board and change the entire scope of global transportation.

Energy, especially solar and wind, cannot be created all over the world. Traditionally, energy is created in situ and shipped to other places that need it. The proposed solutions for zero-carbon energy carriers—batteries and hydrogen—all have their weaknesses. Batteries are a fairly safe option, but their energy density is pretty poor. Hydrogen’s energy density is higher, but its flammability makes it dangerously volatile to store and transport.

Recently, a group of researchers at McGill University in Canada released a paper exploring the use of metal powders as our zero-carbon fuel of the future. Although metal powders could potentially be used as primary energy sources, the transitory solution they propose is to use them as secondary sources powered by wind and solar primaries.

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