Author: Zoe Skyforest

3823 Articles

This FPV Tank Explores The Lawn

December 8, 2019 by 7 Comments

Radio control is good and all, and it’s always fun to watch a little vehicle scoot about the backyard. But there’s always something to be said for feeling as though you’re really in control. First person view, or FPV, is the way to do it, and [Brian] has gone down that route with this tidy tank build.

The tank is 3D printed, from the chassis right down to the wheels. There’s even a moving “eye” up front containing the FPV camera, controlled by a servo, allowing the driver to look up and down. A 5.8 GHz transmitter is used to send the signal back to the driver’s goggles. The tracks are a snap-together design that are fully 3D printed, requiring no additional metal links or hardware. Forward propulsion is courtesy of a pair of 12 volt gear motors, driven from an L298N motor driver. An Arduino Nano is used in conjunction with Spektrum RC gear to receive signals and tell the tank where to go.

It’s a tidy build that would be great fun to drive through the bushes or through the house. We’ve seen even tinier builds used to inspect crawlspaces. If you build one of your own, be sure to let us know.

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Beer Keg Becomes High-Performance Pizza Oven

December 7, 2019 by 14 Comments

Pizza varies all around the world, with several cities having put their own mark on the Italian dish. To make an authentic pie in the Neapolitan style requires extremely high temperatures in order to cook the pizza through in just a couple of minutes. Armed with a beer keg and some ingenuity, [AndrewW1977] got down to work, building a rig that could get the job done.

The build starts by cutting the keg in half. A series of zigzag steel pieces are welded inside, in order to give the refractory cement more surface area to stick to. With the cement poured and set, a handle was welded to the keg for ease of use, as well as a thermometer to monitor internal temperatures.

Initial attempts to cook using the rig used a wood-fired rocket stove design. This had the drawback of taking up to 45 minutes to reach the appropriate temperature, so the build then switched to using God’s Gas, clean burning propane, as a fuel source. With a jet-style burner installed in the base, the oven was ready to start turning out pizzas.

The idea of cooking a hot, fresh pizza in just a couple of minutes has us salivating at the possibilities. We’ve seen other high-speed pizza ovens, too. Video after the break.

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Inkjet Printing On The Cheap With A Continuous Ink System

December 6, 2019 by 39 Comments

Inkjet printers are cheap to buy, but expensive to run. Replacement cartridges can easily cost double the price of the hardware itself, leading many to decry the technology entirely. However, the hackers of the world have the problem licked – enter the continuous ink system.

[cprossu] wanted an affordable color printing solution for the hackerspace. A cheap printer was sourced from a thrift store. The model chosen was selected for its lack of cartridge DRM and the availability of kits on eBay for conversion to a continuous ink system. This involves running large refillable tanks of ink instead of small individual cartridges which must be thrown away when empty.

[cprossu] discusses both the challenges you’ll likely face in a general build, as well as the specific work required to handle the conversion on an Epson Artisan 725. There’s also excessive label-maker abuse, which always brings a smile to our face. It’s a conversion well worth considering if you find yourself regularly purchasing expensive cartridges. We’ve even seen similar builds as far back as 2009, right from the ground up!

Building An Engine With An A/C Compressor

December 4, 2019 by 38 Comments

Air conditioning compressors aren’t exactly a mainstay of the average hacker’s junk box. Typically, they’re either fitted to a car to do their original job, or they’re on the bench getting refurbished. However, with the right mods, it’s possible to turn one into a functioning internal combustion engine.

The build starts by disassembling the compressor, which contains three double-sided pistons. The housing is drilled with ports to allow gas to flow into and out of the cylinders, as well as to transfer from one side of the piston to the other. Acrylic end plates are fitted to the assembly. One end acts as an intake manifold, delivering air and fuel to the cylinders. The other side acts as the cylinder head, mounting the sparkplugs. Everything is then connected with acrylic tubing and a small square section of acrylic is turned into a carburetor to supply the air-fuel mix. Ignition is handled by coils triggered by the movement of the flywheel.

After an initial failure due to the acrylic manifold cracking, a stronger part is fabricated, and the engine bursts into life. The acrylic end caps give a great view of the combustion process in action. We’d love to see the a dyno graph on how much power and torque the unit puts out, or to see it hooked up to a bicycle or cart.

We’ve seen others attempt their own engine builds, too. If you’ve got an unconventional engine build of your own, be sure to let us know. Video after the break.

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Can You Store Renewable Energy In A Big Pile Of Gravel?

December 4, 2019 by 117 Comments

As the world grapples with transitioning away from fossil fuels, engineers are hard at work to integrate new types of generation into the power grid. There’s plenty of challenges, particularly around the intermittent nature of many renewable energy sources. Energy storage projects are key to keeping the lights on round the clock, even when the wind isn’t blowing and the sun isn’t shining.

Conventional grid-level energy storage has long made use of pumped hydro installations where water is pumped uphill to a storage reservoir where it can later be used to run a generator. More recently, batteries are being used to do the job. When you consider the cost of these installations and their storage capacities, there is a gap between batteries and pumped hydro. A recently published whitepaper proposes Mountain Gravity Energy Storage — gravity-based energy storage using sand or gravel in mountainous areas — is the technology that can bridge the gap.

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Building A Mechanical Oscillator, Tesla Style

December 3, 2019 by 12 Comments

Before Tesla devised beautifully simple rotary machinery, he explored other methods of generating alternating current. One of those was the mechanical oscillator, and [Integza] had a go at replicating the device himself. (Video, embedded below the break.)

Initial attempts to reproduce the technology using 3D-printed parts were a failure. The round cylinder had issues sealing, and using O-ring seals introduced too much friction to allow the device to oscillate properly. A redesign that used external valving and a square cylinder proved more successful.

Once the oscillator was complete, the output shaft was fitted with magnets and a coil to generate electricity. After generating a disappointing 0.14 volts, [Integza] went back and had a look at the Maxwell-Faraday equations. Using this to guide the design, a new coil was produced with more turns, and the magnetic flux was maximised. With this done, the setup could generate seven volts, enough to light several LEDs.

While it’s not a particularly efficient generator, it’s a great proof-of-concept. Yes, Tesla’s invention worked, but it’s easy to see why he moved on to rotary designs when it came to real-world applications. We’ve seen [Integza] take on other builds too, like the ever-popular Tesla turbine.

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Cooking A Turkey With 880 AA Batteries

December 2, 2019 by 52 Comments

Cooking a turkey right is serious business this time of year. With major holidays on the line, there’s no room for error – any mistake can leave guests disgruntled and starving. [Stephen Farnsworth] took a risk, though, and attempted to cook a turkey using AA batteries.

The allure of the AA for such a task is precisely because it’s such a poor choice. Designed for portability rather than high power output, it was never designed to be the energy source for a major cooking job. To get things over the line, [Steve] busted out the math to figure out how many batteries would be required. This involved computing cooking efficiencies, battery thermal performance, and the specific heat of the bird itself. With the numbers coming together a 300W slow cooker was put on duty, in order to avoid over-draining the batteries.

With 880 AAs loaded into a custom carrier, [Steve] hooked up the power meter and the cooker and kept a close eye on the temperatures. After a couple of hours, the battery pack started to heat up, so additional cooling was brought in to avoid fire. At just before the six hour mark, the turkey was cooked through and ready to eat. Estimates are that the batteries still had plenty of capacity to keep going for a few hours yet, too.

It’s not a fast or effective way to cook a turkey, but it’s certainly achievable. We fully expect [Steve] to submit the coin-cell turkey cook-off next year, too. Remember, a little engineering always helps, especially in the kitchen. Video after the break.

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