Stop Buying Expensive Circular Saw Blades, Use Paper Instead

[John Heisz] was contemplating the secrets of the universe when an errant thought led him to wonder, could I use a sheet of paper as the blade in my table saw?

He takes a sheet of regular printer paper, draws a circle on it the same diameter as his regular blades, and cuts it out. He then bolts it into place on the spindle, slots in the table saw insert for really really thin kerf blades, and fires it up.

The blade is surprisingly dangerous. One would maybe expect a paper blade to be minimally damaging to a finger at best, but it quickly shows itself to be capable of tearing through paper and cutting through wood at a reasonable clip. Since the paper is minimally conductive, a SawStop couldn’t save someone from a lack of caution.

The blade finally meets its match half way through a half-inch thick piece of wood scrap. Wood and paper dust explode outward as the experiment ends. Video after the break.

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Google Unveils Their Experimental Plan For Wireless Broadband Service

Two years ago, the FCC, with interested parties in Microsoft, Google, and many startups, created the Citizens Band Radio Service (CBRS), a rule that would open up the 3550-3650 MHz band  to anyone, or any company, to create their own wireless backbone between WiFi access points. It is the wireless solution to the last-mile problem, and last year the FCC enthusiastically endorsed the creation of the CBRS.

In a recently released FCC filing, Google has announced their experimental protocol for testing the new CBRS. This isn’t fast Internet to a lamp pole on the corner of the street yet, but it lays the groundwork for how the CBRS will function, and how well it will perform.

Google will be testing the propagation and interference of transmissions in the 3.5 GHz band in places around the US. Most of the Bay Area will be covered in the tests, as well as Boulder, CO, Kansas City, Omaha, Raleigh, NC, Provo, UT, and Reston, VA. Tests will consist of a simple CW tone broadcast in the 3.5 GHz band.

The 3.5 GHz band is already allocated to shipborne navigation and military radar systems, posing an obvious problem to any wireless broadband system using this spectrum. To this end, the FCC is proposing a novel solution to the problem of coexistence between the CBRS and the military. Instead of simply banning transmissions in the spectrum, FCC Chairman Wheeler proposes, “computer systems can act like spectrum traffic cops.” A computer is able to direct the wireless traffic much more effectively than a blanket ban, and will allow better utilization of limited spectrum.

Google’s FCC filing is just for testing propagation and interference, and we have yet to hear anything about how a network built on 3.5 GHz spectrum will be laid out. One thing is for certain, though: you will not have a 3.5 GHz USB networking dongle for the same reason you don’t have a Google Fiber input on your desktop.

Hand-Cranked Cyclotron

Okay, not actually a cyclotron… but this ball cyclotron is a good model for what a cyclotron does and the concepts behind it feel kooky and magical. A pair of Ping Pong balls scream around a glass bowl thanks the repulsive forces of static electricity.

It’s no surprise that this comes from Rimstar, a source we’ve grown to equate with enthralling home lab experiments like the Ion Wind powered Star Trek Enterprise. Those following closely will know that most of [Steven Dufresne’s] experiments involve high voltage and this one is no different. The same Wimshurst Machine he used in the Tea Laser demo is brought in again for this one.

A glass bowl is used for its shape and properties as an insulator. A set of electrodes are added in the form of aluminum strips. These are given opposite charges using the Wimshurst machine. Ping Pong balls coated in conductive paint are light enough to be moved by the static fields, and a good crank gets them travelling in a very fast circuit around the bowl.

When you move a crank the thought of being connected to something with a chain pops into your mind. This feels very much the same, but there is no intuitive connection between the movement of the balls and your hand on the crank. Anyone need a prop for their Halloween party?

If you don’t want to buy or build a Wimshurst machine you can use a Van De Graaff generator. Can anyone suggest other HV sources that would work well here?

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Measuring The Lifespan Of Nixie Tubes

nixie

Nixie tubes have two things going for them: they’re awesome, and they’re out of production. If you’re building a clock – by far the most popular Nixie application, you’re probably wondering what the lifespan of these tubes are. Datasheets from the manufacturers sometimes claim a lifetime as low as 1000 hours, or a month and a half if you’re using a tube for a clock. Obviously some experimentation is in order to determine the true lifetime of these tubes.

Finding an empirical value for the lifetime of Nixies means setting up an experiment and waiting a very, very long time. Luckily, the folks over at SALTechips already have a year’s worth of data.

Their experimental setup consists of an IN-13 bargraph display driven with a constant current sink. The light given off by this Nixie goes to a precision photometer to log the visual output. Logging takes place once a week, and the experiment has been running for 57 weeks so far.

All the data from this experiment is available on the project page, along with a video stream of the time elapsed and current voltage. So far, there’s nothing to report yet, but we suppose that’s a good thing.

Hackit: Researchers wait 69-years to see tar move

69-year-science-experiement

This experiment was started at Trinity College Dublin way back in 1944. Its purpose is to prove that tar flows, and indeed it does let go of a drop about every ten years. The thing is that nobody has ever seen that happen, bringing up the “if a tree falls in the forest” scenario. The Nature article on this event even mentions another experiment whose last drop was missed because the camera monitoring it was offline. This time around they did get some footage of the (un)momentous event which you can see below.

So here’s the challenge for clever hackers: What’s the easiest rig you can think of that won’t just continuously film the experiment but can also ensure that you get the goods on tape when a drop does fall? We see all kinds of high-speed shutter triggers — here’s one of the latest. But we don’t remember seeing an extremely slow version of the same. Let us know your idea by leaving a comment.

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Only you can kick a child’s balls into space

We had a lot of fun with that title. Of course when you’re talking about launching a thousand ping pong balls into space there’s no end to the puns which can be made. But this is actually a fantastic initiative to get people of all ages excited about science and near-space experiments. [John Powell] offers school children the opportunity to send an experiment into space. He’s Kickstarting the next launch, which is scheduled to take place in September. This way each entrant can fly their project for free, then get the results and a certificate back once the weather-balloon-based hardware is recovered.

There is one size restriction for the program. Each experiment must fit inside of a ping pong ball. But you’ll be surprised what can be accomplished. [John] reports that the most simple, yet interesting project is to place a small marshmallow inside the ball. As it rises through the atmosphere it will grow to fill the entire ball, then be freeze-dried by the the extreme temperatures. Some are not so low-tech. There’s an image of a tiny PCB holding a DS1337 and some sensors. It’s an atmospheric data logger that will provide plenty of information to analyze upon its return.

[via Hacked Gadgets]

Hackers age 14-18 can compete to put their project into space

If you’re between the ages of 14 and 18, or have a child who is, here’s a chance to put a project into space. NASA is partnering with YouTube, Lenovo, and a few other entities for a contest that challenges participants to dream up low-gravity experiments. You can enter as an individual or in teams of up to three people, and may put forth up to three experiment ideas for judging. Getting in on the first round is as easy as recording and uploading a video. You’ll need to state a scientific question or principle you want to test, a hypothesis of what can be learned, and a method for testing it.

As with most of the projects we encounter, the seminal idea is always the toughest part. And since the folks here at Hackaday are too old to enter, we thought we’d propose throwing around some ideas in the comments to get the ball rolling (the contest FAQ says it’s okay to get help from others so we’re not ruining it for everyone). We’ll go first.

It looks like experiments can be Biology or Physics related, and can’t use hazardous chemicals, weapons, or anything sharp. We’d love to see some tests that measure how well electronic sensors work in the microgravity. For instance, can you use a gyroscope sensor reliably in micro-gravity? What about an electronic compass; does it always point toward earth? What about robotic propulsion? We’d love to see a minature ROV swimming through the air like a water-bourne vessel would on earth.

Your turn. Leave a comment to let us know what you’d do if you could enter. Oh, and we’ve also embedded the contest promo video after the break.

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