Preserve your garden bounty with a solar food drier

solar-food-drier

The [VelaCreations] family lives off the grid, getting the electricity that they actually use from solar and wind power. When they started looking for ways to preserve the fruit and vegetables now coming into harvest the electricity consumption and cost of a food dehydrator made them balk. What they do have plenty of at this time of year is sun and heat, so they built their own solar food drier.

The frame is made of welded square tube. They mention that you will have to alter it if you don’t have welding tools, but building your own MOT welder is just one more fun project to take on. The frame has wood rails to hold the trays of food. It is enclosed with translucent polycarbonate sheets. There is a vent in the top as well as the bottom. As the heat from the sun builds inside, it flows upward, sucking fresh air in the bottom. This carries away moisture from the food and can be regulated by adjusting the size of the bottom vent.

Motorized skateboard controlled by hand gestures

hand-gesture-skateboard

This rough-looking contraption is a hand gesture controlled skateboard which [Aditya] built using parts on hand. So far the sensor for hand gestures is connected by a control wire, but he hopes to transition to an RF unit at some point in the future.

Having access to a couple of high torque brushless motors is what turned him onto the project. He hit up a couple of Mechanical Engineer friends of his to help assemble the chassis and then started on the electronics side of things. A breakout board for an ATmega16 is mounted on the corner of the deck. It monitors an accelerometer which acts as steering as well as throttle. The accelerometer had been abused in a previous project so he had to add an extra switch to bolster his available inputs. We were glad to hear that he also included a kill switch, since putting the control of those motors in the hands of a damaged accelerometer is a bit sketchy.

We remember seeing a similar trike design a few years back. That one powered a single rear wheel while this one powers two wheels and uses a caster for the third.

Here Be Dragons, and VR…and sheep.

dragonVR

This may qualify less as a hack and more as clever combination of video game input devices, but we thought it was well worth showing off. [Jack] and his team built Dragon Eyes from scratch at the 2013 Dundee Dare Jam. If you’re unfamiliar with “Game Jams” and have any aspirations of working in the video game industry, we highly recommend that you find one and participate. With only 48 hours to design, code, build assets and test, many teams struggle to finish their entry. Dragon Eyes, however, uses the indie-favorite game engine Unity3D to smoothly coordinate its input devices, allowing players to experience dragon flight. The Kinect reads the player’s arm positions (including flapping) to direct the wings for travel, while the Oculus Rift performs its usual job as immersive VR headgear.

Combining a Kinect and a Rift isn’t particularly uncommon, but the function of the microphone is. By blowing into a headset microphone, players activate the dragon’s fire-breathing. How’s that for interactivity? You can see [Jack] roasting some sheep in a demonstration video below. If you have a Kinect and Rift lying around and want some first-person dragon action, [Jack] has kindly provided a download of the build in the project link above.

We’re looking forward to more implementations of the Rift; we haven’t seen many just yet. You can, however, check out a Rift used as an aerial camera on a drone.

[Read more...]

A deck screw extruder

deck

A lot of great ideas happen in the middle of the night, and for [Werner] it’s no different. One night he came up with an idea for a new 3D printer extruder, and after a very basic prototype, we’d have to say he might be on to something. It’s basically a deck screw acting as a worm gear to drive filament, but this simple idea has a lot of really cool advantages.

There are two really interesting features of this extruder, should [Werner] ever decide to flesh out his idea into a real prototype. First, the stepper motor for this extruder can be extremely small and mounted directly above the extruder. This opens up the doors to easily creating multi-extrusion printers that can handle more than one filament. Secondly, using a deck screw as a worm gear means there is a huge area of contact between the plastic filament and the driver gear.

Whereas the usual extruder setup only makes contact with the plastic filament along one or two splines of a hobbed bolt, [Werner]‘s design drives the filament along the entire length of the deck screw worm gear. This could easily translate into much more accurate extrusion without all the fiddling around with springs and hobbed bolts today’s extruders have.

In any event, it’s a very interesting idea, and we’d love to see [Werner] or someone else make a functioning extruder with this design.

One pixel video game rises from RGB button hardware

rgb-button-one-pixel-video-game

This project was completely component driven. [Christopher] and [Robert] wanted to try out buttons with an RGB backlight option. They found the one shown above, which looks fantastic. It should since it costs over twenty bucks in single units. What they came up with is a one pixel video game that works like a color matching version of Simon Says. The button will show you the target color for just a moment. The player then holds the button as it fades through colors. Releasing it at the right instant will produce a green flash, a wrong shade results in a red flash.

They went with an Arduino Mega for the project as that was within easy reach. A hunk of protoboard is used as a shield, it includes the button itself, connected through some current limiting resistors to the pins that drive the LED. There is also a tactile switch which actuates the AVR’s reset pin.

When trying to get the LED to fade through the full range of colors [Christopher] was hit with a common problem. Since our eyes don’t detect changes in low and high intensity light the same way, you can’t use linear changes in PWM and get a smooth result. He fixed this by using Gaussian curves to set the intensity levels.

[Read more...]

Getting SPI on a router

router

Cheap routers such a s the TP-LINK 703n and the TP-LINK MR3020 (seen above) can be used for much more than just connecting your laptop to your cable modem. They’re actually very small Linux boxes and with OpenWRT, you can control every aspect of these tiny pocket-sized computers. It’s frequently been suggested that these routers are awesome substitutes for the usual methods of getting Internet on a microcontroller, but how do you actually do that? The onboard serial port is a great start, but this also dumps output from the Linux console. What you need here is an SPI connection, and [ramcoderdude] has just the solution for you.

Linux already has a few SPI modules, but these are only accessible with kernel drivers. Traditionally, the only way to access SPI is to recompile the kernel, but [coderdude] created a kernel module that allows any device running the Attitude Adjustment OpenWRT image to dynamically allocate SPI busses.

He’s already submitted this patch to the OpenWRT devs, and hopefully it will be included in future updates. Very cool, we think, and something that can open a whole lot of doors for hacking up routers very easily.

HHO generator makes bubbles that go boom

hho-generator

Here’s [Phil] showing off the components he used to make an HHO generator. The device uses household items to generate hydrogen and oxygen from water using electrolysis.

He’s using a plastic Nesquik container as the vessel for his experiment. Inside is water doped with a bit of baking soda. The lid plays host to the majority of components. There are electrodes which stick through the lid of the container. To help boost the productivity of the generator these electrodes have several metal washers suspended between. It’s importnat to avoid a short circuit so they’re mounted with the plastic bolt from a toilet seat, and isolated using hot glue. A plastic tube used collects the gasses. You can tweak the ratio of what’s being collected by reversing the polarity of the battery.

It’s interesting to see soap bubbles lit on fire in the demo video. But there are more serious uses for this concept. People have been working on making it feasible to power cars from the hydrogen generated this way. We’ve also seen a plastic bottle rocket powered from an HHO generator, and there’s always the thought of building your own miniature dirigible.

[Read more...]

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