Teslaphoresis: Tesla Coil Causes Self-Assembly In Carbon Nanotubes

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This significant discovery in nanotechnology could also be the first practical use of a Tesla coil in modern times that goes beyond fun and education. A self-funded research team at Rice University has found that unordered heaps of carbon nanotubes will self-assemble into conductive wires when exposed to the electric field of a strong Tesla coil. The related paper by lead author and graduate student [Lindsey R. Bornhoeft], introduces the phenomenon as “Teslaphoresis”. Continue reading “Teslaphoresis: Tesla Coil Causes Self-Assembly In Carbon Nanotubes”

ESP8266 Based Irrigation Controller

If you just want to prevent your garden from slowly turning into a desert, have a look at the available off-the-shelf home automation solutions, pick one, lean back and let moisture monitoring and automated irrigation take over. If you want to get into electronics, learn PCB design and experience the personal victory that comes with all that, do what [Patrick] did, and build your own ESP8266 based irrigation controller. It’s also a lot of fun!

[Patrick] already had a strong software background and maintains his own open source home automation system, so building his own physical hardware to extend its functionality was a logical step. In particular, [Patrick] wanted to add four wirelessly controlled valves to the system.

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Automatic Book Scanner To Bring Knowledge To Ethiopian Students

In 2013 the dean of an Ethiopian university addressed Maker Faire Hannover and outlined one of his concerns; that the high price of developed-world textbooks was holding back the cause of education for universities such as his own in developing countries. He was there to ask for help from the maker community to solve his problem, and a group of his audience took up the challenge to create an affordable and accessible automatic book scanner.

Their scanner builds on the work of Google engineer [Dany Qumsiyeh], whose open source linear book scanner turns pages by traversing the opened book over a triangular prismic former such that pages are turned by vacuum as they pass over carefully designed slots in its surface. Their modification replaces the vacuum with the Coandă effect, to more gently tease open each page and it is hoped reduce the chance of damaging the volumes being scanned.

The whole machine is controlled by a Raspberry Pi, and the scanning is performed by linear scanning optics, sensors, and electronics taken from flatbed scanners.

An important design goal of the project was to ensure that the scanner could be built without special tools or expertise that might be difficult to find in a developing country, as well as that it should be as inexpensive as possible. The frame of the machine is off-the-shelf extruded aluminium, and the body is acrylic sheet which can be cut to shape with a hand saw if necessary. It is estimated that the device will cost in the region of 500 Euros (about $568) to build.

More information can be found at the project’s web site (German language, Google translate link), including a selection of videos such as the one below the break showing the device in operation.

Writing from the perspective of having been peripherally involved in a professional book scanning operation at a large publisher the benefits of this machine are immediately apparent. Removing the binding and automatically scanning each page as an individual sheet produces a very fast and high quality result, but by its very nature damages the volume being scanned. This machine promises to deliver a solution to the problem of book scanning that is considerably less intrusive.

It is also worth noting that the project does not address any copyright issues that might arise from scanning commercially published textbooks, though this is more of a concern for the end user in terms of what they scan with it than it is for the maker.

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Most Of What You Wish You Knew About Coils Of Wire But Were Afraid To Ask

If you are a novice electronic constructor, you will become familiar with common electronic components. Resistors, capacitors, transistors, diodes, LEDs, integrated circuits. These are the fodder for countless learning projects, and will light up the breadboards of many a Raspberry Pi or Arduino owner.

There is a glaring omission in that list, the inductor. True, it’s not a component with much application in simple analogue or logic circuits, and it’s also a bit more expensive than other passive components. But this omission creates a knowledge gap with respect to inductors, a tendency for their use to be thought of as something of a black art, and a trepidation surrounding their use in kits and projects.

We think this is a shame, so here follows an introduction to inductors for the inductor novice, an attempt to demystify them and encourage you to look at them afresh if you have always steered clear of them.

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Rotating Plasma Vortex Speaker

[Anthony Garofalo] has made a fancier plasma speaker. Not content with a simple spark, he uses a plasma vortex. To make the vortex, the spark gap is swapped out for an electrode placed in the centre of a ring magnet. The Lorentz force experienced by the arc causes it to rotate rapidly enough round the arc of the magnet’s centre to appear as a continuous sheet of plasma.

The speaker gets its power from an inverter using a flyback transformer driven through a MOSFET by a 555-based pulse width modulator. You can see the result in the video below the break, it’s very impressive to look at but probably not quite ready to sit in your hi-fi stack. The resulting sound isn’t quite as good as that from a stationary arc, but it looks a lot cooler.

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Small And Inexpensive MEMS Gravimeter

A gravimeter, as the name suggests, measures gravity. These specialized accelerometers can find underground resources and measure volcanic activity. Unfortunately, traditional instruments are relatively large and expensive (nearly 20 pounds and $100,000). Of course, MEMS accelerometers are old hat, but none of them have been stable enough to be called gravimeters. Until now.

In a recent edition of Nature (pdf), researchers at the University of Glasgow have built a MEMS device that has the stability to work as a gravimeter. To demonstrate this, they used it to measure the tides over six days.

The device functions as a relative gravimeter. Essentially a tiny weight hangs from a tiny spring, and the device measures the pull of gravity on the spring. The design of the Glasgow device has a low resonate frequency (2.3 Hz).

Small and inexpensive devices could monitor volcanoes or fly on drones to find tunnels or buried oil and gas (a job currently done by low altitude aircraft). We’ve covered MEMS accelerometers before, although not at this stability level.  We’ve even seen an explanation from the Engineer Guy.

Make a BLDC Motor From Scraps You Can Find In The Garage

Think you’ve got what it takes to build a homebrew brushless motor? As [JaycubL] shows us, it turns out that a bldc motor may be living in pieces right under your nose, in scraps that so many of us would otherwise toss aside. To get our heads turning, [JaycubL] takes us into the theory of brushless DC motors operate. He then builds a homebrew brushless motor using screws, a plastic container, a few bearings, a metal rod, some magnets, and a dab of epoxy. Finally, he gives it a whirl with an off-the-shelf motor controller.

This isn’t [JaycubL’s] first dive into homebrew brushless motors. For the curious, he’s also assembled a fully-functional brushless outrunner motor with a paint can housing.

Sure, understanding the principles is one thing, but being able to take the leap into the real world and find the functional beginnings of a motor from your scrap bin is an entirely different story! [JaycubL’s], dare we say, finesse of understanding the principles behind motor design makes us wonder: how many other functional higher-level electrical and mechanical components can we bootstrap from bitter scrap? To get you started, we’ll point you in the direction of this CNC router that’s just a few steps away from one trip to the hardware store.

Thanks for the tip, [John]!

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