Carabiner helps you hone your milling skills

[Christian] is learning to use the metal milling tools at what we assume is his local Hackerspace. We love this about the communal spaces, they provide so many opportunities to delve into new fields. He embarked on a voyage that included visits to most of the machinery in the shop as he build his own carabiner with a magnetic gate. He’s not going to be hanging off the side of a mountain from it. But his keys or a water bottle will find a happy home thanks to the device.

It all started with some sketches to establish the shape of the overall design. From there he spent some time modelling the frame of the carabiner in CAD. He’s lucky enough to have access to a water jet which took the SolidWorks files and cut out the aluminum frame for him. That left a part with very sharp edges, so he used a wood router with a carbide bit to round them over.

The next part is adding the gate. He used an end-mill to add a mounting area on the frame. The locking ring for the gate was textured using a knurling tool, and the rest is milled with a simple cutting tool. This gate uses a magnet to center itself, with the knurled ring as the only mechanical latching mechanism. [Christian] does a good job of demonstrating the completed carabiner in the clip after the break.

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Chocolate as rocket fuel

[Adric Menning] has an unfortunate allergy. He’s allergic to chocolate. Instead of eating the stuff, he’s using it to build model rocket engines. The project stems from the Quelab Hackerspace’s chocolate hacking challenge which spawned a number of interesting hacks. [Adric’s] doesn’t use pure chocolate (an experiment with a Hershey’s bar was a bust) but manages to ignite using a Milky Way bar.

This is not as unorthodox as you might think. Sugar and potassium nitrate have long been used to create solid rocket propellant. The chocolate version is swapping out plain old sugar for the candy bar. It was chopped into 10 gram chunks to make proportion calculations easier later on. The chunks go into the freezer to make them easier to grind using a mortar and pestle. Once it’s a somewhat chunk-free powder he mixes it with the potassium nitrate which previously had its own trip through the grinder. After being packed into a chunk of PVC pipe and fitted with an exhaust nozzle the engine is ready to go.

You can check out the test-fire video after the break. There’s a burn restriction in his area due to drought so this is just an engine test and not an actual rocket launch.

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Adding a lot of twinkle to this rebar sculpture

Blinky lights have a way of attracting attention and that’s exactly what the members of the Maui Makers hackerspace were shooting for. The sculpture above is the logo for the Source festival, a Burning Man inspired music gathering in the Aloha state. For this year’s festival they went crazy, installing twelve meters of RGB LED strip controlled by seven Arduino boards.

The goal was to make the twelve-foot tall sculpture into a lighted interactive showpiece. In addition to the LEDs it includes a microphone, capacitance sensors, Bluetooth connectivity, and a piezo speaker. There’s one Arduino to rule them all, with another Teensy controller to drive an LCD display in the control box, and five Teensy boards to address the LED strips. They grabbed [Bill Porter’s] Easy Transfer library to facilitate communication between the microcontrollers (his libraries are becoming popular, we just saw his mp3 shield library used in another project on Tuesday).

The code which drives the LED animations is based on some Adafruit examples. We really enjoy the waving flag effect seen in the clip after the break.

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Klackerlaken gets the common man excited about electronics

The Klackerlaken is a combination of LED throwie and bristlebot. The bauble is easy to build and really has no other purpose than to delight the masses. The diminutive devices were first seen in the wild at the 2011 CCC (Chaos Communications Camp) as a hands-on workshop. Check out the clip after the break and you’ll see why this really sucks in the spectators.

We’ve seen a ton of Bristlebots before (this tiny steerable version is one of our favorites) and were intrigued to see bottle caps used as the feet instead of the traditional toothbrush head. In fact, that video clip shows off several different iterations including two caps acting as an enclosure for the button cell and vibrating motor. Googly eyes on the top really complete the look on that one.

Decorating the robots with LEDs, fake eyes, tails, and feathers helps to temper the technical aspects that kids are learning as they put together one of their own. We’re glad that [Martin] shared the link at the top which covers the creations seen at a workshop held by Dorkbot Berlin. This would be a great activity for your Hackerspace’s next open house! Perhaps its possible to have follow-up classes that improve on the design, using rechargeable cells instead of disposable buttons, or maybe supercaps would work.

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Heatless compressed air dryer

The pressurized air from a standard air compressor is fine for most uses. But some applications like plasma cutting call for low-humidity air and the hardware available to facilitate this can cost a bundle. [Roland] and his cohorts at TX/RX Labs (a Houston, Texas Hackerspace) just built this air drying system.

It works using a desiccant; a substance that sequesters moister. It’s the stuff in those little packets you find in shoe boxes and the like with a warning that you shouldn’t eat it. The image above shows two chambers which house the desiccant. Only one is used at a time, so that as it’s ability to remove moisture drops, the system can switch over to the other chamber. There’s even an automatic recharging system built in that uses a portion of the dried air to remove the humidity from the unused desiccant chamber.

There’s a functional diagram at the link above. It’s resolution is low enough that the text is almost unreadable but we’ve asked [Roland] if he can repost the image. This seems like a build in which other hackerspaces will be interested.

Robot overlords require chores in return for technological access

Looks like you might not be fully immersed in the digital world if you didn’t complete your chores. The members of the LVL1 Hackerspace have put together a lot of automation for their lair, but nothing drives home the utility of the system they call MOTHER like the shenanigan-preventing trash removal system. Or in layman’s turns, being nagged by MOTHER until you empty the trash can.

So here’s a bit of background first. Remember that sensor array that just had way too many environmental sensors on it? That is just one way that the automation system (MOTHER) measures its surroundings. It seems the hackerspace has been building a pile of scripts to interface with just about every aspect of the community.

For instance, the night before trash colletion the system starts by letting members know it’s trash night and someone needs to empty the garbage. There’s a pressure sensor under the can which alerts MOTHER to the fact that it has been moved. But what if nobody moves the can? Say goodbye to Google. Yep, it’ll block all Google searches until the chore is done. And that’s just one punishments in its bag of tricks.

So what if you just move the can and don’t take it out? No dice. MOTHER is also monitoring the garage door which needs to be open to get the extra-large can out to the dumpster. You’ve got five minutes to do that before she starts getting nasty.

[Thanks Jonathan]