Adding payload to an RC cessna

For just a few bucks you can add a payload to your flying toys. In this case it’s a Cessna RC plane which now has an added surprise. The first thing to be dropped was a parachute with a weight on it (for testing purposes). But there are hints of future projects that will use the same system for different purposes.

As you can see in the image above, the system depends on an additional compartment attached to the bottom of the plane. It was built from foam board to keep the weight down and connects using rare earth magnets. The bottom of the enclosure acts as the door, hinging on a servo motor with a bamboo skewer as the axle. So far the test drops have gone pretty well, but some more work needs to be done with the parachute design. It only opens about 60% of the time. We can sympathize, having had to work out some of our own parachute issues.

Don’t miss video from the plane as well as the ground after the break.

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Bamboo Bike

Reddit user [tkgarrett101] recently did away with expensive exotic materials for his bike frame and opted for a somewhat less processed form of natural building material, bamboo! The bike consists of a regular metal bike frame with a majority of the structural beams cut and replaced with bamboo poles. The bamboo is fit snug first with some expanding gorilla glue then tied in place with  hemp string and fiberglass resin. Instead of running cables along the frame the bike has coaster breaks brakes and a two speed hub, this also preserves the simplistic look of the whole ensemble. [tkgarrett101] says his bike is not so cheap, the overall parts cost was around 800 bucks (USD)! Plus it weighs a whole lot for a fixed gear. Plus the alignment is a bit off on the seat post. Either way this thing would surely turn some heads!

Too rich for your blood? Check out this cardboard bike, or if that green isn’t bright enough for you how about some glowbars for night visibility.

via Reddit

Box Maker extension for Inkscape

If you use Inkscape to lay out your laser cutter designs you might want to look into this box maker extension. Inscape is [Elliot's] drawing software of choice since it’s easy to use, and it’s open source. After having to lay out the tabs for a box he decided it was worth his effort to develop a tool to do this automatically. The extension works inside of Inkscape, letting you start your projects with a set of automatically generated box sides.

The input window for the extension leaves you plenty of options for the joint design. In addition to the size of the box (inside or outside measurements can be selected), you need to enter the thickness of the material, the kerf size (how wide the cut will be), and how much clearance you want between the teeth. The width of the teeth is also configurable.

Our feature of a laser cut replacement case is what prompted [Elliot] to tip us off about his extension. That project used a web-based parts generator to do the joint design.

Don’t ignore the middle of the country!

“Nothing happens in the midwest”. I won’t say who said it, but it absolutely makes my blood boil. I’ve heard this several times during my time at Hackaday. Aside from being so insanely arrogant and dismissive, it is also completely inaccurate.

Some people believe you absolutely have to be on a coast to be part of anything interesting. In the modern age of the internet, geographical location is becoming less and less of an issue. People are collaborating on projects that span the world. Here at hackaday we see projects quite daily that are spawned from a forum linking hackers to a common theme with virtually no central geographical point.  Robots, video games, open source software, tools, and art installations have all sprung from the diaspora that is the hacker culture without any necessity for being located on a coast.

With tools like 3d printers becoming common in hackerspaces collaboration on physical design is even being spread geographically. You could be in your garage in Arkansas, assembling a machine that was designed by someone in Minnesota, and inserting code that was uploaded by someone in Kansas!

Sure, we all know the coasts are great. High concentrations of like minded people as well as the culture you can find anywhere near the ocean. But please, don’t ignore the middle, it makes you sound like antiquated ass.

Make your own custom iPhone back glass

[Jake von Slatt] is at it again; putting his own artistic spin on ordinary items. This time around it’s the glass on the back of an iPhone. It kept breaking and after a few replacements he wanted to try to replace the glass with a piece of etched brass. But part way through that experiment, he figured out how to use toner transfer to develop these stunning custom iPhone glass back plates.

The first step is to source the correct replacement back for your phone. These are made of two parts, the glass and a plastic backer. By carefully heating and wedging the two parts with some popsicle sticks he was able to separate the pieces. Next, he cleans and buffs the glass, preparing it for the artwork he is about to apply. Toner transfer paper, just like that used for PCB resist, is used to print and adhere a design to the underside of the glass. From there he hand paints over the black outline to achieve the results seen above.

It takes time and patience, but shouldn’t be any harder than etching a circuit board.

Know thy enemy: Open vias in BGA footprints

[Andrew Zonenberg] has crossed a line in his electronic hobby projects. The Ball Grid Array (BGA) is a type of chip footprint which most hobbyists leave to the professionals. But he’s learned the skills necessary to use them in his projects. Recently he ran a test batch to show off his soldering process and illustrate one of the errors a novice might make.

For those that are unfamiliar, the BGA footprint is notoriously difficult to accurately solder because it consists of a large grid of tiny points covering the bottom of the chip. There’s no way to get in there with an iron, so soldering depends on accurate placement of solder paste and chip, as well as a near-perfect reflow cycle. Often times it’s difficult for the professionals too. Many blame the heat-failure of Xbox 360 on the complications of the BGA connects for one of the console’s chips.

For this experiment [Andrew] wanted to show what happens if you include vias in the BGA footprint. It’s fine to do so, as long as they’re capped. But if a standard via is included, capillary action ends up pulling the solder down into the via instead of making a connection with the chip. The image above is a cross-section of one such uncapped via, seen on the far right.

[Thanks George]

Visualizing heat with Schlieren photography

[Kevin] wanted to check out the air patterns present when his 3D printer is in action. This is useful research; slight differences in temperature can affect the quality of his prints. Instead of something like a thermometer, [Kevin] decided to use Schlieren photography to visualize the air around his 3D printer.

If you’ve ever seen very old-school pictures of supersonic research, you’ve seen Schlieren photography. It’s a way of visualizing the density of transparent objects using only mirrors, lenses, and a point light source. The resulting pictures are usually black and white, although some amazing color pictures exist of bullets traveling through the air next to soap bubbles and candles.

The process of creating a Schlieren photograph is actually pretty easy. [Kevin] pointed a light at a used a 4-inch parabolic mirror placed behind his printer. A knife edge is placed at exactly twice the focal length of the mirror, and after putting a camera behind this knife edge, differences in the density of the air are visible.

From [Kevin]‘s video of his Schlieren setup (available after the break), you can see the air is extremely turbulent around his print. That might have been obvious given the presence of a cooling fan, but it’s still very, very cool to look at.

[Read more...]

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