Will Supercapacitors Ever Replace Batteries?

January 19, 2017 by Manuel Rodriguez-Achach 124 Comments

Recharging your mobile phone or your electric vehicle in a few minutes sure sounds appealing. Supercapacitor technology has the potential to deliver that kind of performance that batteries currently can’t, and while batteries are constantly improving, the pace of development is not very fast. Just remember your old Nokia mobile with Ni-Cad batteries and several days of usage before a recharge was needed. Today we have Lithium-Ion batteries and we have to charge our phones every single day. A better energy storage option is clearly needed, and supercapacitors seem to be the only technology that is close to replace the battery.

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[Marla]’s New Arm

January 19, 2017 by Jenny List 32 Comments

It is especially rare to see coverage in the mainstream media that involves a hackspace, so it was a pleasant surprise yesterday when the local TV news where this is being written covered a story that not only highlighted a hackspace’s work, but did so in a very positive light.

[Marla Trigwell] is a young girl from Newbury, UK, who was born without a left hand. She had been provided with prosthetics, but they aren’t cheap, and as a growing child she quickly left them behind. Her parents researched the problem as modern parents do, and found out about recent advances in 3D-printed prosthetics lowering the bar to access for those like [Marla] born without a limb. Last month [Marla] received her new 3D-printed arm, and she did so courtesy of the work of [Andrew Lindsay] at Newbury and District Hackspace.

The arm itself is a Team Unlimbited arm version 2.0 Alfie edition, which can be found on Thingiverse with full sizing instructions for adjusting to the recipient in Customizer. As the video below the break shows, [Marla] appears very pleased with it, and is soon mastering its ability to grip objects.

This story is a fantastic demonstration of the ability of a hackspace to be a force for good, a true community organisation. We applaud [Andrew], NADHack, and all involved with it for their work, and hope that 3D printed arms will keep [Marla] with a constant supply of comfortable and affordable prosthetics as she grows up.

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Print Flexible PCBs With A 3D Printer

January 19, 2017 by Al Williams 21 Comments

Let’s get it out of the way right up front: you still need to etch the boards. However, [Mikey77] found that flexible plastic (Ninjaflex) will adhere to a bare copper board if the initial layer height is set just right. By printing on a thin piece of copper or conductive fabric, a resist layer forms. After that, it is just simple etching to create a PCB. [Mikey77] used ferric chloride, but other etchants ought to work, as well.

Sound simple, but as usual, the devil is in the details. [Mikey77] found that for some reason white Ninjaflex stuck best. The PCB has to be stuck totally flat to the bed, and he uses spray adhesive to do that. Just printing with flexible filament can be a challenge. You need a totally constrained filament path, for one thing.

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Use A Brushless Motor As A Rotary Encoder

January 18, 2017 by Jenny List 17 Comments

The electric motor is the fundamental building block of almost all robotic projects but, without some form of feedback, it lacks the precise positional control required for the task. Small servos from the modelling world will often use a potentiometer to sense where they are on their travel, while more accomplished motors will employ some form of shaft encoder.

Commercial shaft encoders use magnets and Hall-effect sensors, or optical sensors and encoder discs. But these can be quite expensive, so [Hello1024] hacked together an alternative in an afternoon. It uses another motor as the encoder, taking advantage of the minute changes in inductance as the magnet passes each of its coils. It’s a technique that works better with cheaper motors, as their magnets are more imperfect than those on their expensive cousins.

The sensing is rather clever in its economy, sending a pulse to the motor through an off the shelf motor controller and measuring the time it takes to decay through the body diode of the driving MOSFET. It requires a calibration procedure before first use, and it is stressed that the whole thing is very much still in beta, but it’s a very impressive hack nevertheless. He’s posted a video demonstration which you can see below the break.

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Programming Thousands Of AVRs

January 18, 2017 by Al Williams 24 Comments

It is funny how almost everything has its own set of problems. Rich people complain about taxes. Famous people complain about their lack of privacy. It probably won’t happen us, but some Kickstarter campaigners find they are too successful and have to scale up production, fast. We’d love to have any of those problems.

[Limpkin] found himself in just that situation. He had to program several thousand Atmel chips. It is true that you can get them programmed by major distributors, but in this case, he wanted unique serial numbers, cryptographic keys, and other per-chip data programmed in. So he decided to build his own mass programming workbench.

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Lean Thinking Helps STEM Kids Build A Tiny Windfarm

January 18, 2017 by Dan Maloney 35 Comments

When we see a new build by [Gord] from Gord’s Garage, we never know what to expect. He seems to be pretty skilled at whatever he puts his hand to, with a great design sense and impeccable craftsmanship. You might expect him to tone it down a little for a STEM-outreach wind turbine project then, but when you get a chance to impress 28 fifth and sixth graders, you might as well go for it.

Starting with an idea from his daughter’s teacher for wind turbines each kid could make, [Gord] applied a little lean methodology so the kids would be able to complete the build in the allotted time. The design is simple – a couple of old CDs holding vertical sections of PVC tubing to catch the breeze and spin neodymium magnets over four flat coils of magnet wire. It’s enough to light a single LED and perhaps a kid’s imagination.

As simple as the turbine is, the process of building it needed to be stripped of as much unnecessary work as possible, and [Gord] really shines here. He built jigs and fixtures galore, pre-built some assemblies, and set up well-organized workstations for each step of the build. Everything was clearly labeled, adult volunteers were trained using the video after the break, and a good time was had by all.

Sometimes the hack isn’t in the product but in the process, and [Gord] managed to hack a success out a potential disaster of disappointed kids. If getting a taste of [Gord]’s style makes you want to see more, check out his guitar fretting jig or his brake rotor mancave clock.

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A No-Solder, Scrap-Bin Geiger Counter For $15

January 18, 2017 by Dan Maloney 30 Comments

Scenario: your little three-hour boat tour runs into a storm, and you’re shipwrecked on a tropic island paradise. You’re pretty sure your new home was once a nuclear test site, but you have no way to check. Only your scrap bin, camera bag, and hot glue gun survived the wreck. Can you put together a Geiger-Müller counter from scrap and save the day?

Probably not, unless your scrap bin is unusually well stocked and contains a surplus Russian SI-3BG miniature Geiger tube, the heart of [GH]’s desert island build. These tubes need around 400 volts across them for incident beta particles or gamma rays to start the ionization avalanche that lets it produce an output pulse. [GH]’s build uses the flash power supply of a disposable 35mm camera to generate the high voltage needed, but you could try using a CCFL inverter, say. The output of the tube tickles the base of a small signal transistor and makes a click in an earbud for every pulse detected.

You’ll no doubt notice the gallons of hot glue, alligator clips, and electrical tape used in the build, apparently in lieu of soldering. While we doubt the long-term robustness of this technique, far be it from us to cast stones – [GH] shows us what you can accomplish even when you find yourself without the most basic of tools.

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