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

April 14, 2016 by Jenny List 59 Comments

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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Hoverboards Are Here – If You’re Crazy Enough To Try

April 14, 2016 by Adam Fabio 87 Comments

A new video has been stirring questions on the internet this week. It shows a test of the Flyboard Air, a device that is somewhere between a Back to the Future Hoverboard and Green Goblin’s glider. The video depicts pilot [Frank Zapata] taking off, flying around, and landing an a platform not much larger than a milk crate. Plenty of folks are calling the video a fake. After a few back of the napkin calculations though, we’re coming out to say we think it’s real. Details are few and far between, so much of the information in this article is educated guessing based upon the video.

Here’s our hypothesis: Flyboard Air is a jet powered platform with little or no built-in intelligence. Balance, stability and control are all handled by the pilot. A hand controller simply provides throttle to adjust altitude, take off, and land.

Let’s start with the jet powered part. During the video, [Frank] looks down at his board and the water below. Between his sneakers we can see two round openings – which look a lot like jet intakes. At the end of the video, [Frank] flies over the camera. stopping the action shows a split second where four exhaust holes are visible on the bottom of the board. These jets look quite a bit like model aircraft jet engines.

We don’t know exactly which engines [Frank] is using, but as an example, the Jet-Cat P 400 RX-G packs 88 lbs of thrust into a shell less than 6 inches in diameter, weighing less than 8 lbs. Four of those engines would provide 352 lbs of thrust. That’s plenty to lift [Frank], the board, and a few gallons of Jet-A strapped to his back.

Why no built-in intelligence? Even the smallest quadcopters have gyros, accellerometers, and PID loops keeping them upright. The problem boils down to the physics of jet engines. Active stability in a fixed pitch rotary blade system requires very fast throttle response. Quadcopters have this with their brushless motors. Turbines however, have throttle lag on the order of seconds. You can’t beat physics. Accelerating 3 or 4 pounds metal from 78,000 RPM (~70% throttle) to 98,000 RPM (~100 % throttle) takes time.

Standing on a column of uncontrolled thrust would take quite a bit of skill on the part of the pilot. As it turns out, [Frank] is one of the world’s most experienced thrust riders. His previous invention, the Flyboard uses a personal watercraft to create a column of thrust which the rider stands on. These boards have become tremendously popular at vacation spots in the last few years. There are plenty of videos on [Frank’s] YouTube channel showing the amount of control a skilled ride has over the board. Loops, spins, and other aerobatics look easy.

With that much skill under his belt, [Frank] would have no problem keeping balanced on four jet engines.

Such a skilled rider means that control wouldn’t really be needed on the board. We’re betting that the only electronics are the remote throttle control and the Engine Control Computers (ECU) needed to keep the jets running and synchronized. The two electric ducted fans on the sides of the Flyboard Air appear to be running all the time, only shutting down when [Frank] lands the board.

One final thought – taking off and landing a jet vertically is difficult. Ground effects destabilize the craft. Engines can suck in their own exhaust, stalling them. These are problems faced by the harrier jump jet and the joint strike fighter. [Frank’s ] solution is not never get too close to the ground. If you watch closely, he takes off and lands from a perforated metal platform mounted off the back of a van. The metal doesn’t reflect enough thrust to cause the Flyboard to become unstable or stall.

So is the video real? We think so. This is an amazing achievement for [Frank Zapata]. Is it practical or safe? Heck no! Nor is it cheap – those engines cost €8,845.00 each. That said, we’d love a chance to ride the Flyboard Air – after a few hours of training on the original Flyboard of course.

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3D Printed Microscope Chamber Saves Big Bucks

April 14, 2016 by Al Williams 4 Comments

Optical microscopy is over 400 years old, and in that time, it has come a long way. There are many variations of microscopes both in the selection of lenses, lighting, and other tricks to allow an instrument to coax out more information about a sample.

One proven way to increase the resolving power of a microscope is oil immersion. The sample and the lens are placed in oil that is transparent and has a high refractive index. This prevents light from refracting at the air-coverslip interface, improving the microscope’s overall performance.

The University of New South Wales has a lab that uses such a microscope. They use a special (and expensive) chamber to hold down the glass coverslip and contain the oil. The problem? At nearly $400 a pop, the chambers are a constant expense to replace, and they are not flexible enough to handle custom size requirements.

[Ben Goodnow], a first year student at the university, applied his 3D printing and laser cutting know-how to design and build a suitable chamber that costs much less and can be adapted to different projects. In addition to all the design files on GitHub, there’s also a document (PDF) that describes the design iterations and the total cost savings.

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CarontePass: Open Access Control For Your Hackerspace

April 13, 2016 by Jenny List 27 Comments

A problem faced by all collaborative working spaces as they grow is that of access control. How can you give your membership secure access to the space without the cost and inconvenience of having a keyholder on site at all times.

[Torehc] is working on solving this problem with his CarontePass RFID access system, at the Kreitek Makerspace (Spanish, Google Translate link) in Tenerife, Canary Islands.

Each door has a client with RFID readers, either a Raspberry Pi or an ESP8266, which connects via WiFi to a Raspberry Pi 2 server running a Django-based REST API. This server has access to a database of paid-up members and their RFID keys, so can issue the command to the client to unlock the door. The system also supports the Telegram messaging service, and so can be queried as to whether the space is open and how many members are in at a particular time.

All the project’s resources are available on its GitHub repository, and there is a project blog (Spanish, Google Translate link) with more details.

This is a project that is still in active development, and [Torehc] admits that its security needs more work so is busy implementing HTTPS and better access security. As far as we can see through the fog of machine translation at the moment it relies on the security of its own encrypted WiFi network, so we’d be inclined to agree with him.

This isn’t the first hackerspace access system we’ve featured here. The MakerBarn in Texas has one using the Particle Photon, while the Lansing Makers Network in Michigan have an ingenious mechanism for their door, and the Nesit hackerspace in Connecticut has a very fancy system with video feedback. How does your space solve this problem?

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Bacon Beacon

April 13, 2016 by Jenny List 13 Comments

The device featured here is quite simple, but it’s well executed and involves bacon, so what’s not to like!

They take their bacon sandwiches seriously in Dundee. And let us tell you, in Scotland they make good bacon! At the co-working space where [Grant Richmond] works, people were missing out on the chance to order when someone went to the bacon sandwich emporium for a refill.

His solution was the Bacon Beacon, a nicely lasercut box with a series of buttons on top connected to a Particle Photon microcontroller. Press a button, and a node.js web app is called on a server, which in turn sends notifications to the “Fleeple”, the inhabitants of the Fleet Collective co-working space. They can then reply with the details of their order, such as their desired sauce.

The work of sending the notifications is done through Pushbullet, but the code for [Grant]’s side of things can all be found on his GitHub repository. The whole thing was put together in Dundee MakerSpace.

We have something of an affinity for bacon and cured meat products here at Hackaday, we’ve featured more than one bacon-related exploit. The Rabbit Hole hackerspace’s “Push button, receive bacon” cooking system using a laser printer fusing roller for example, an alarm clock that cooks your tasty treat, or a full cooked breakfast using workshop tools.

Please keep them coming, and resolve to make space for a bacon-related hack this year. We promise, it won’t be one of your rasher decisions.

A Partwork As A Hackspace Course

April 13, 2016 by Jenny List 3 Comments

If you watch a lot of TV just after Christmas, you will be familiar with partworks. Or at least, you will if you live in the part of the world this is being written from, and if you aren’t you should count yourself lucky. The premise is simple: buy this magazine once a month, and in each issue you will receive a fresh component which you can assemble over time into a beautiful model of a galleon, a Lancaster bomber, or a patchwork quilt.

The value for money offered by such publications is highly suspect, the quality of the finished item is questionable, and though the slick TV adverts make them sound alluring you’re much better off buying the Airfix model kit or just cutting your own patches.

There’s a partwork that caught our eye which may be worth a second look. It’s probably unfair on reflection to call it a partwork though as it doesn’t deserve to be associated with the scammier end of the publishing business. Swansea Hackspace are currently running a six-week all-inclusive course designed to introduce the participant to robotics through a step-by-step assembly of an Arduino based robot. Tickets were £60 ($85) to hackspace members, and all parts were included in that price.

At first sight it might seem a little odd to feature a course. It’s not a hack, you’ll say. And though the little Arduino robot is a neat piece of kit, you’d be right. It’s hardly ground-breaking. But the value here doesn’t lie in the robot itself, but in the course as an exercise in community engagement. If you are involved in the running of a hackspace perhaps you’ll understand, it can sometimes be very difficult to persuade timid visitors to come along more than once, or to join the space. Hackspaces can be intimidating places, after all.

The Swansea course holds the promise of addressing that issue, to say to an interested but non-expert newcomer that they needn’t worry; if they have an interest in robotics then here’s a way to learn. This community engagement and spreading of knowledge reveals an aspect of the hackspace movement that sometimes remains hidden, and it’s something we’d like to see more of in other spaces.

Powering A Lot Of Nixie Tubes

April 13, 2016 by Brian Benchoff 43 Comments

[Limpkin] has an idea for a project that uses a lot of IN-9 Nixie tubes. Where a Nixie tube clock would only use four or six tubes, [Limpkin] is looking at fifty IN-9 bar graph Nixie tubes. These tubes only light up above 100 Volts and draw about half an amp. That’s 64 Watts, according to the math on the project page, so how does [Limpkin] plan on powering these tubes? With a big high voltage power supply.

The power supply [Limpkin] designed is more or less what you would expect to find in any power supply. There’s a transformer, a bunch of caps, and a rectifier. Going with a standard laminated core transformer would mean this power supply would be huge and heavy, but once again eBay comes to the rescue with a small, 150 Watt toroidal transformer. The largest output on the transformer was two 24 V outputs. Combining those outputs gets [Limpkin] to 48V AC, or 68V peak to peak. A full wave voltage doubler with two caps and two diodes gives [Limpkin] the 136V DC that will power the tubes.

Combine the high voltage circuit with a 9V AC tap, a small bridge rectifier, and a few more caps, and [Limpkin] had a supply that would power the tubes and the rest of the electronics in his multiple Nixie tube project. A few passes with a CNC mill gave the power supply a nice case topped off with a foreboding toroidal transformer ready to power a beautiful neon project.