Looking Forward To EMF Camp: Teasing Us With A Schedule

May 9, 2022 by Jenny List 5 Comments

As we gear up for a summer in the field, or more accurately in a series of fields, it’s time to turn our attention towards Eastnor Castle in the Western English county of Herefordshire, venue for the upcoming Electromagnetic Field hacker camp. Sadly we’ve got no badge to tease you with, but they’ve released a list of the talks that will fill their schedule. There are so many to choose from, we can only mention a few in this article.

We’ll certainly be taking the time to watch [Russell Couper] describe his electric motorcycle project. He’s no stranger to unusual bike builds, having given us a diesel machine at EMF 2016. Then of course there’s our own [Dave Rountree], who will be hacking the radio spectrum with GNU Radio. Sure to be an interesting talk.

One feature of this camp we’re very interested in will be CuTEL, a wired copper telephone network on the field. We’ll be taking along our trusty GPO 746 to be part of it of course, but for those without one, there’s [Matthew Harrold]’s talk on building a copper telephone network in a field.

Our cursory scan of the list finishes up with [Alistair MacDonald] on how not to start a hackerspace. We’ve seen our fair share of hackerspace drama over the years, so whether this one causes pain for ex-hackerspace-directors or not, it promises to be informative for anyone in the hackerspace world.

At the time of writing there are still some EMF tickets for sale, so if the beginning of your June is free we can heartily recommend it. To get a flavour of the event, read our 2018 review.

DIY Machine Enables PEMF Therapy On A Budget

August 29, 2021 by Tom Nardi 48 Comments

We’re certainly not qualified to say whether or not pulsed electromagnetic field (PEMF) therapy will actually reduce your stress or improve your circulation, but there seems to be enough legitimate research going on out there that it might be worth a shot. After all, unless you’ve got a pacemaker or other medical implant, it seems pretty unlikely a magnetic field is going to make anything worse. Unfortunately commercial PEMF machines can cost thousands of dollars, making it a fairly expensive gamble.

But what if you could build one for as little as $10 USD? That’s the idea behind the simple DIY PEMF machine [mircemk] has been working on, and judging by its ability to launch bits of metal in the video below, we’re pretty confident it’s indeed producing a fairly powerful electromagnetic field. Even if it doesn’t cure what ails you, it should make an interesting conversation piece around the hackerspace.

While the outside of the machine might look a bit imposing, the internals really are exceptionally straightforward. There’s an old laptop power supply providing 19 VDC, a dual-MOSFET board, a potentiometer, and a simple signal generator. The pulses from the signal generator trip the MOSFET, which in turn dumps the output of the laptop power supply into a user-wound coil. [mircemk] has a 17 cm (6.7 inch) open air version wrapped with 200 turns of copper wire used for treating wide areas, and an 8 cm (3 inch) diameter version with 300 windings for when you need more targeted energy.

Some skepticism is always in order with these sort of medicinal claims, but commercial PEMF machines do get prescribed to users to help promote bone growth and healing, so the concept itself is perhaps not as outlandish as it might seem.

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A Crust-Cutting, Carrot-Chopping Robot

November 30, 2020 by Kristina Panos 9 Comments

[3DprintedLife] sure does hate bread crust. Not the upper portion of homemade bread, mind you — just that nasty stuff around the edges of store-bought loaves. Several dozen hours of CAD later, [3DprintedLife] had themselves a crust-cutting robot that also chops vegetables.

This De-Cruster 9000 is essentially a 2-axis robotic guillotine over a turntable. It uses a Raspberry Pi 4 and OpenCV to seek and destroy bread crusts with a dull dollar store knife. Aside from the compact design, our favorite part has to be the firmware limit switches baked into the custom control board. The stepper drivers have this fancy feature called StallGuard™ that constantly reads the back EMF to determine the load the motor is under. If you have it flag you right before the motor hits the end of the rail and stalls, bam, you have a firmware limit switch. Watch it remove crusts and chop a lot of carrots with faces after the break.

This is far from the dangerous-looking robot we’ve seen lately. Remember this hair-cutting contraption?

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Electromagnetic Field 2020 Cancelled

March 25, 2020 by Jenny List 4 Comments

It’s the news we were all expecting but not looking forward to hearing: this summer’s EMF Camp which was to be held at the end of July in Herefordshire, UK, has been cancelled. This is of course due to the ongoing public health measures surrounding the COVID-19 virus pandemic. With the country on lockdown for the forseeable future, this is a responsible decision for a gathering the size of EMF which hosted around 2,500 attendees in 2018.

Existing ticket holders will be refunded, and will be guaranteed a ticket to the next event in 2022. According to the announcement, EMF is in the red to the tune of at least £25,000 ($29,523) because of non-refundable payments associated with booking the event, something to remember in two years time when faced with the choice of a normal ticket or a supporters ticket.

Work on starting conference badge production has been halted, but development continues apace and will not go to waste as it will form the basis of the 2022 item. This will make them the event badge team with the earliest preparation ever, and from what we saw when we had a brief look at an early prototype last year it should be a badge worth waiting for.

We’re sure all readers will understand the gravity of the situation, and that the EMF team have taken an appropriate response to what is an extraordinary series of events. Organising a hacker camp is a tough job at the best of times, and this must have been particularly hard on them. We thank them for their work on our behalf at previous events and in preparing for this aborted one, and we look forward to the next EMF Camp in 2022.

Teardown: Nihon Kenko Magnetic Wave Tester

April 15, 2019 by Tom Nardi 35 Comments

You never know what kind of wonders you’ll find on eBay, especially when you have a bunch of alerts configured to go off when weird electronic devices pop up. You may even find yourself bidding on something despite not being entirely sure what it is. Perhaps you’re a collector of unusual gadgets, or maybe it’s because you’ve committed to doing monthly teardowns for the hacker blog you work for. In any event, you sometimes find yourself in possession of an oddball device that requires closer inspection.

Case in point, this “Magnetic Wave Tester” from everyone’s favorite purveyor of high-end electronics, Nihon Kenko Zoushin Kenkyukai Corporation. The eBay listing said the device came from an estate sale and the seller didn’t know much about it, but with just a visual inspection we can make some educated guesses. When a strong enough magnetic field is present, the top section on the device will presumably blink or light up. As it has no obvious method of sensitivity adjustment or even a display to show specific values, it appears the unit must operate like an electromagnetic canary in a coal mine: if it goes off, assume the worst.

If you’re wondering what the possible use for such a gadget is, you’re not the only one. I wasn’t able to find much information about this device online, but the few mentions I found didn’t exactly fill me with confidence. It seems two groups of people are interested in this type of “Magnetic Wave Tester”: people who believe strong magnetic fields have some homeopathic properties, or those who think it will allow them to converse with ghosts. In both cases, these aren’t the kind of users who want to see a microtesla readout; they want a bright blinking light to show their friends.

So without further ado, let’s align our chakras, consult with the spirits, and see what your money gets you when you purchase a pocket-sized hokum detector.

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The Enlightenment Turns Light And Noise Into Sound

March 16, 2019 by Lewin Day 24 Comments

We’re all familiar with the subtle sounds of electrical equipment present in daily life. There’s the high-pitched whine of a CRT, the mains hum of a poorly isolated audio amplifier, and the wailing screams of inductors. Typically these sounds go unnoticed unless something is malfunctioning or otherwise wrong. However, Quiet Ensemble decided to capture these noises and turned them into a performance they call The Enlightenment.

The basic setup consists of a series of lights, most of which are theatrical in nature. There are spotlights, a series of neons, and even a few bright strobes. Copper coils are used to pick up the stray electrical noises generated by these lights in operation. These noises are then fed to mixers, amplifiers, and other audio equipment to allow the performers to control the audio as they wish.

The end result is a mechanical, and at times, brutal soundscape that wouldn’t sound out of place on the Homeworld soundtrack. Flashing strobes contribute rhythm while the rest of the lights lend their droning and whining to fill out the ensemble.

If it’s a little too niche for your tastes, the Triforium may be more to your liking. Video after the break.

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GSM Phone Network At EMF Camp Built On Raspberry Pi And LimeSDR

August 30, 2018 by Jenny List 22 Comments

The Electromagnetic Field 2018 hacker camp in the UK will have its own GSM phone network, and as we have already covered its badge will be a fully-functional GSM phone. This is as far as we are aware a first in the world of badges, and though it may not be a first in hacker camp connectivity it is still no mean achievement at the base station side. To find out more we talked to two of the people behind the network, on the radio side Lime Microsystems‘ [Andrew Back], and on the network side Nexmo‘s developer advocate, [Sam Machin].

There are sixteen base stations spread around the site, of which each one is a Raspberry Pi 3 B+ with a LimeSDR Mini. Development of the system was undertaken prior to the release of the Raspberry Pi Foundation’s PoE board, so they take a separate 24V supply which powers the Pi through a DC-to-DC converter. This arrangement allows for a significant voltage drop should any long cable runs be required.

On the software side the base stations all run the Osmocom (Open Source Mobile Communications) cellular base station infrastructure package. It was a fine decision between the all-in-one Osmocom NITB package and the fully modular Osmocom, going for the former for its reliability. It was commented that this would not necessarily be the case at a future event but that it made sense in the present. It appears on the network as a SIP phone system, meaning that it can easily integrate with the existing DECT network. Let’s take a look at how the network operates from the user side, and the licencing loophole that makes everything possible.

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