What’s Inside A Scientology E-Meter?

July 19, 2018 by Brian Benchoff 146 Comments

This is something we’ve been waiting a very long time for. The Church of Scientology uses devices called E-Meters to measure Thetans in the body. We’re not going to discuss this further, because we don’t want to be murdered. In reality, the E-Meter is simply a device that costs five thousand dollars and only measures the resistance of the human body. It does this by having the subject hold two copper cylinders and a simple Wheatstone bridge. Why does the E-Meter cost five thousand dollars? As [Play With Junk] found out, it’s an exquisitely engineered piece of hardware.

[Play With Junk] acquired this E-Meter from eBay for something around $100, and from a system-level analysis, it’s really not anything special. There’s a fancy analog meter, yes, but most of this wouldn’t be out of place in any 90s-era piece of test equipment. There’s an 8051 microcontroller reading what are probably some fancy ADCs, and there’s an LCD driver on board. Slap it in a fancy injection-molded case, and you have an E-Meter.

What’s most impressive is the quality of the components that go into a machine that effectively only measures the resistance of the human body. The ‘trim’ pot is a Vishay wire-wound precision potentiometer that costs somewhere between $20 and $60. The power switch is an over-specced switch that probably costs $5. The control pots look and feel great, and the wiring is wrapped around chokes.

This is an exceptionally well-engineered device, and it shows. There’s an incredible amount of work that went into the electronics, and a massive amount of money that went into the fancy injection molded enclosure. If you’re looking for an example of a well-engineered tool, price be damned, you need only look at an E-Meter.

Check out the video below of the entire teardown.

Continue reading “What’s Inside A Scientology E-Meter?” →

A Farewell To Printrbot

July 19, 2018 by Tom Nardi 71 Comments

It’s with a heavy heart that we must report Printrbot has announced they are ceasing operations. Founded in 2011 after a wildly successful Kickstarter campaign, the company set out to make 3D printing cheaper and easier. Their first printer was an amalgamation of printed parts and wood that at the time offered an incredible deal; when the Makerbot CupCake was selling for $750 and took 20+ hours to assemble, the Printrbot kit would only run you $500 and could be built in under an hour.

Printrbot got their foot in the door early, but the competition wasn’t far behind. The dream of Star Trek style replicators fueled massive investment, and for a while it seemed like everyone was getting into the 3D printing game. Kit built machines gave way to turn-key printers, and the prices starting coming down. Printrbot’s products evolved as well, dropping wood in favor of folded steel and pioneering impressive features like automatic bed leveling. In 2014 they released the Printbot Simple Metal, which ultimately became their flagship product and in many ways represents the high water mark for the company.

Eventually, overseas manufacturers saw an opportunity and started flooding the market with 3D printers that were cheaper than what many would have believed possible only a few years earlier. Today you can go online and buy a perfectly serviceable starter printer for under $200, even less if you’re still willing to build it yourself. For an American company like Printrbot, competing at this price point was simply an impossibility.

Rather than give up, Brook decided to take things in a different direction. If he couldn’t compete with imported machines on price, he would start building high end printers. A new version of the Simple Metal was introduced in 2016 with premium features such as linear rails and cloud-based slicing, complete with a premium price. From that point on, most new Printrbot products would release at over $1,000; putting them more in line with “prosumer” machines from companies like Ultimaker. For hacker types who got their first taste of 3D printing thanks to a cheap wooden Printrbot kit, this was something of a bittersweet moment.

At the same time, Brook’s natural hacker spirit and love of the open source community lead to a number of interesting side projects that never quite got off the ground. Most recently, he’d been putting the finishing touches on the Printrbelt, a 3D printer with a conveyor belt in place of a traditional bed. Such a machine could finally bridge the gap between desktop 3D printing and true small scale production capability.

When we saw Brook at the East Coast RepRap Festival, he brought along a new machine that the more cynical observer might have taken as foreshadowing. The Printrbot Easy was going to be a modified and rebranded FlashForge Finder, a final acknowledgement that the only way to compete with the Chinese manufactured 3D printers was to sell one of your own.

It’s always sad to see a tech company go under, but seeing the end of Printrbot is especially hard. Built in America with locally sourced components and with a commitment to keeping their machines open source, there was a lot to love about the plucky little 3D printer company from Lincoln, California. Printrbot was the quintessential hacker success story, and we’re proud to say we’ve been in their corner from the start. Here’s to wishing Brook Drumm and the entire Printrbot team success in their future endeavors; we’ll be keeping an eye out.

Let’s Talk About Elon Musk’s Submarine

July 17, 2018 by Tom Nardi 223 Comments

When word first broke that Elon Musk was designing a kid-sized submarine to help rescue the children stuck in Thailand’s Tham Luang cave, it seemed like a logical thing for Hackaday to cover. An eccentric builder of rockets and rocket-launched electric sports cars, pushing his engineering teams and not inconsiderable financial resources into action to save children? All of that talk about Elon being a real life Tony Stark was about to turn from meme into reality; if the gambit paid off, the world might have it’s first true superhero.

With human lives in the balance, and success of the rescue attempt far from assured (regardless of Elon’s involvement), we didn’t feel like playing arm-chair engineer at the time. Everyone here at Hackaday is thankful that due to the heroics of the rescuers, including one who paid the ultimate price, all thirteen lives were saved.

Many said it couldn’t be done, others said even saving half of the children would have been a miracle. But Elon’s submarine, designed and built at a breakneck pace and brought to Thailand while some of the children were still awaiting rescue, laid unused. It wasn’t Elon’s advanced technology that made the rescue possible, it was the tenacity of the human spirit.

Now, with the rescue complete and the children well on their way to returning to their families, one is left wondering about Elon’s submarine. Could it have worked?

Continue reading “Let’s Talk About Elon Musk’s Submarine” →

Getting The Lead Out Of Lithium Battery Recycling

July 16, 2018 by Dan Maloney 74 Comments

When that fateful morning comes that your car no longer roars to life with a quick twist of the key, but rather groans its displeasure at the sad state of your ride’s electrical system, your course is clear: you need a new battery. Whether you do it yourself or – perish the thought – farm out the job to someone else, the end result is the same. You get a spanking new lead-acid battery, and the old one is whisked away to be ground up and turned into a new battery in a nearly perfect closed loop system.

Contrast this to what happens to the battery in your laptop when it finally gives up the ghost. Some of us will pop the pack open, find the likely one bad cell, and either fix the pack or repurpose the good cells. But most dead lithium-based battery packs are dropped in the regular trash, or placed in blue recycling bins with the best of intentions but generally end up in the landfill anyway.

Why the difference between lead and lithium batteries? What about these two seemingly similar technologies dictates why one battery can have 98% of its material recycled, while the other is cheaper to just toss? And what are the implications down the road, when battery packs from electric vehicles start to enter the waste stream in bulk?

Continue reading “Getting The Lead Out Of Lithium Battery Recycling” →

Behind The Pin: How The Raspberry Pi Gets Its Audio

July 13, 2018 by Jenny List 54 Comments

Single board computers have provided us with a revolution in the way we approach computing as hardware creators. We have grown accustomed to a world in which an entire microcomputer has become a component in its own right rather than a complex system, and we interface to them as amorphous entities through their exposed interfaces. But every pin or socket on a single board computer has something behind it, so following up on a recent news-inspired item in which we took a look at what lies behind the Ethernet jack on a Raspberry Pi, we’d like to continue that theme by looking behind more pins and interfaces. So today we’ll stay with the Raspberry Pi, and start with an easy target by taking a look down its audio jack.

All the main Raspberry Pi board releases since 2012 with the exception of the Pi Zero series, have featured a 3.5mm jack carrying line-level audio. The circuits are readily accessible via the Raspberry Pi website, and are easy enough to understand because of course all the really hard work is done within the silicon of the Broadcom system-on-chip. Looking at the audio circuitry, we’ll start by going back to the original Pi Model B from 2012 (PDF) because though more recent models have seen a few changes, this holds the essence of the circuitry.

Continue reading “Behind The Pin: How The Raspberry Pi Gets Its Audio” →

Teardown Of USB Fan Reveals Journalists’ Lack Of Opsec

July 11, 2018 by Brian Benchoff 109 Comments

Last month, Singapore hosted a summit between the leaders of North Korea and the United States. Accredited journalists invited to the event were given a press kit containing a bottle of water, various paper goods, and a fan that plugs into a USB port.

Understandably, the computer security crowd on Twitter had a great laugh. You shouldn’t plug random USB devices into a computer, especially if you’re a journalist, especially if you’re in a foreign country, and especially if you’re reporting on the highest profile international summit in recent memory. Doing so is just foolhardy.

This is not a story about a USB fan, the teardown thereof, or of spy agencies around the world hacking journalists’ computers. This a story of the need for higher awareness on what we plug into our computers. In this case nothing came of it — the majority of USB devices are merely that and nothing more. One of the fans was recently torn down (PDF) and the data lines are not even connected. (I’ll dive into that later on in this article). But the anecdote provides an opportunity to talk about USB security and how the compulsion to plug every USB device into a computer should be interrupted by a few seconds of thoughtfulness first.

Continue reading “Teardown Of USB Fan Reveals Journalists’ Lack Of Opsec” →

Ham-designed Gear Used In Thailand Cave Rescue

July 11, 2018 by Al Williams 41 Comments

Unless you live in a cave, you’ve probably heard a little about the thirteen people — mostly children — trapped in the Tham Luang Nang Non cave in Thailand. What you may have missed, though, is the hacker/ham radio connection. The British Cave Rescue Council (BCRC) was asked for their expert help. [Rick Stanton], [John Volanthen] and [Rob Harper] answered the call. They were equipped with HeyPhones. The HeyPhone is a 17-year-old design from [John Hey, G3TDZ]. Sadly, [G3TDZ] is now a silent key (ham radio parlance for deceased) so he didn’t get to see his design play a role in this high-profile rescue, although it has apparently been a part of many others in the past.

The HeyPhone is actually considered obsolete but is still in service with some teams. The radio uses USB (upper sideband, not universal serial bus) at 87 kHz. The low frequency can penetrate deep into the ground using either induction loop antennas like the older Molephone, or — more commonly — with electrodes injecting RF energy directly into the ground.

Continue reading “Ham-designed Gear Used In Thailand Cave Rescue” →