Manpowered PVC Rollercoaster

Swing sets and jungle gyms are good enough for your average back yard. But if you want to go extreme you need to build your own backyard roller coaster.

This impressive offering uses PVC pipe for the rails. At its tallest it stands 12 feet, using pressure treated 4×4 lumber as the supports. Pressure treated spacers span the tracks, with the uprights — which are cemented in place — in the center.

You can get a better look at it in the video after the break. This is a parent-powered system. Strap you kid in and then use a stick to push the car up to the top of the hill. We just love it that before the kart has made it back to the start the child is already screaming “again daddy”!

It doesn’t look quite as fast as the metal back yard roller coaster we saw some time ago. But we do wonder how they bent the PVC pipes and whether they’re strong enough to pass the test of time (especially being exposed to the sunlight)? [Read more...]

Announcing: International Hack Day, August 11th.

There is no single and definitive definition of what hacking is. We all have different versions of similar ideas in our head, but depending on your background and area of enthusiasm, hacking means something different. While dictionary.com has many definitions of the word itself, none seem to cover what we see on a daily basis.

We set out to define “hacking” ourselves. We tossed around words like “modify”, “kludge”, “explore”, and “create”. Each time we committed an increasingly vague definition onto the page, we decided it was too narrow and tossed it in the proverbial trash. The variations were just too many.

What we do know is that “hacking” seems to breed advancement and innovation. Much like mutations in an evolutionary chain, each hack pushes the topic in a slightly new direction, inspiring others and thereby perpretuating the evolutary event. In a very short time we’ve witnessed hacking bring forth the evolution of wagons to cars, kites to airplanes, and the creation of the computer.

We at Hackaday would like to declaire August 11th to be “International Hack Day”. A day to celebrate hacking in all of its diverse forms. From soldering to sewing, coding to carbonating, knitting to knurling, we want you to keep on hacking. Take August 11th as a day to show pride in your hacking. Waive your hacker flag high and educate those around you.

We have asked many of our friends to contribute their personal definition of hacking. Here they are, in the order they were received.

[Read more...]

Seeing through walls using WiFi

Turns out you don’t need to be Superman to see through walls. Researchers at University College London have developed a way to passively use WiFi as a radar system. Unlike active radar systems (which themselves send out radio waves and listen for them to echo back), passive radar systems cannot be detected.

The system is small enough to fit in a briefcase, and has been tested through a one-foot-thick brick wall. It can detect position, speed, and direction of a person moving on the other side of that wall, but cannot detect stationary object. [Karl Woodbridge] and [Kevin Chetty], the engineers behind the prototype, think it can be refined to pick up motion as minuscule as a person’s rib cage moving with each breath. For some reason we get the picture in our mind of that body scanner from the original Total Recall.

[via Reddit]

[Image Credit]

Blinking light switch

In addition to being a great replacement for that aging eye patch, these specs act as a light switch. By watching your eyelids, they are able to kill the lights whenever you blink.

The installation is a shared experience piece conceived by [Michal Kohút]. He wanted to illustrate the constant blinking we all do but rarely think about. The system uses an Arduino to capture events from the blink sensors and switch the lights accordingly. This way the wearer doesn’t experience a loss of illumination, but the observer does. Check out the video after the break for a quick demonstration.

One of the commenters from the source article shared a video link to another blink-based light project. That one uses electrodes attached to skin around your eye in order to detect eyelid motion.

[Read more...]

Building a coal forge

We don’t get to see Blacksmith hacks around here too often. But even if they were rolling in on a weekly basis we think this one would be considered the special expanded edition with full-color centerfold. The sixty-five images in this coal forge build log are all commented and just begging to steal your attention for part of the afternoon.

The build mostly involves fabricating a system for injecting air into the forge and providing a mechanism for evacuating the waste ash. [BillDaCat] starts with a 3″ pipe as the ash dump, adding a latching door used to empty it when full. He then welds together a metal trough with a slotted bottom to hold the fiery fury, attaching the ash dump below. He uses a plasma cutter to add an opening in the upper portion of the ash dump for a blast gate.

If you’re excited about his build you should also check out the metal pour and the induction furnace.

[via Reddit]