Belt The Quarantine Blues Into A Homemade Mic

April 12, 2020 by Kristina Panos 15 Comments

If there’s any psychological good to be gleaned from quarantine, it’s that people are using the time to finish old projects while starting plenty of new ones. If you’re running out of ideas, or just want to feel better by doing some in-house recycling, dump out that bin and make a simple microphone.

All you need is some PETE #1 plastic, a piezo disk, and the right kind of tin can. The plastic gets heat-fused to the rolled edge of the can, and since it gets stretched and shrunk in the process, it forms a tight membrane that doubles as a percussion instrument.

You do your shouting into the other end, and your sound waves vibrate the membrane. The piezo picks up the vibrations and sends them to a 1/4″ jack so you can plug it into an amp.

Even if you are somehow sidestepping the blues, you can always use this to yell at people who threaten to get too close to you. This fun project is about as open as it gets, but we’re sure that you can think of ways around using a piezo disk. Let us know in the comments after you check out [Ham-made]’s music video.

We like [Ham-made]’s method for cutting down the juice jug without cutting into yourself. Just clamp a razor blade into your vise and move jug against it. Reminds us of another way to easily reuse plastic soda bottles by making them into rope.

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To Deal With Plastic Trash, All You Need Is Bugs

April 27, 2017 by Dan Maloney 24 Comments

Outlawed now in some places, or only available to tote your purchases at a ridiculous premium, the billions of “T-shirt” bags used every year present a serious waste management problem. Whether blowing across the landscape like synthetic tumbleweeds, floating in the ocean as ersatz jellyfish, or clogging up municipal waste streams, finding a way to deal with them could really make a difference. And finding a bug that eats polyethylene and poops antifreeze might be a great first step in bioremediating the mess.

As with many scientific discoveries, learning about the useful and unexpected eating habits of the larval stage of the Greater Wax Moth Galleria mellonella can be chalked up to serendipity. It began when biochemist [Federica Bertocchini] cleaned a wax moth infestation from her beehive. She put the beeswax-loving pests in a plastic bag, later finding they had chewed their way out. Intrigued, she and [Paolo Bombelli] ran some experiments using the bugs. They showed the mechanism wasn’t just mechanical and that the worms were digesting the polyethylene, to the tune of 92 mg consumed for 100 worms in 12 hours. That’s about 1,000 times faster than bioremediation with bacteria.

Furthermore, the bugs excrete ethylene glycol, a useful industrial chemical, in the process. Finally, to see if the process can scale, the researchers showed that a homogenate of wax moth larvae could digest PE sheets. This could lead to an industrial process if the enzymes involved can be isolated and engineered. The letter describing the process is a fascinating read.

While this one may not a classically hackish way to deal with plastic recycling, the potential for this method is huge. We look forward to seeing where this goes.

[Images: César Hernández/CSIC]

Soda Bottles Used As Heat-Shrink For Wood Joinery

March 23, 2017 by Dan Maloney 80 Comments

Nobody is likely to confuse it with the beautiful joinery that makes fine furniture so desirable. But as a practical technique, using plastic bottles as heat-shrink tubing for composite joints is pretty nifty, and the pieces produced are not without their charm.

Undertaken as an art project to show people what can be done with recycled materials, [Micaella Pedros]’ project isn’t a hack per se. She started with bottles collected around London and experimented with ways to use them in furniture. The plastic used in soda and water bottles, polyethylene terephthalate (PET), turns out to shrink quite a bit when heated. Rings cut from bottles act much like large pieces of heat-shrink tubing, but with more longitudinal shrinkage and much more rigidity. That makes for a great structural component, and [Micaella] explored several ways to leverage the material to join wood. Notches and ridges help the plastic grip smoother pieces of wood, and of course the correct size bottle needs to be used. But the joints are remarkably strong – witness the classic leaning-back-in-a-chair test in the video below.

Its aesthetic value aside, this is a good technique to file away for more practical applications. Of course, there are plenty of ways to recycle soda bottles, including turning them into cordage or even using them as light-pipes to brighten a dark room.

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