From the archive, originally posted by: [ spectre ]


Unsafe At Any Amperage?

by Tom Anderson, Gareth Branwyn, Shawn Connally, Dale Dougherty, Mark Frauenfelder, Joe Grand, Saul Griffith, William Gurstelle, Bunnie Huang, Tom Igoe, Mister Jalopy, Steve Lodefink, David Pescovitz, Charles Platt, Paul Spinrad, Phillip Torrone, John MacNeill / March 16, 2007

“Behind the scenes of our high-voltage dilemma: whether to publish a dangerously cool project in MAKE magazine’s “Fringe” issue.

DANGER: HIGH VOLTAGE! Do not attempt this project without expert assistance unless you are an adult experienced in working with extremely high voltage power sources. This project is intended only for very experienced adults. Severe injury, death, or property damage may result from failure to use adequate safety gear and precautions.

What’s more important: empowering readers to take control of technology, or protecting them from the risks? A spirited discussion between MAKE’s editors and technical advisory board ultimately led us to cancel publication of the high-voltage “Lifter” project in Volume 09.

The piece was written by John MacNeill, a well-known illustrator whose work appears frequently in publications such as Popular Science. MacNeill is also a “lifter” hobbyist who has made several of the mysterious levitating devices, and the how-to project he submitted was excellent. We were very excited to run it. However, MAKE’s technical advisory board, consisting of engineers, how-to book authors, and researchers, deemed the project to be unsafe, due to the project’s high voltage conducted across exposed wires in a flying object. Would strong warnings suffice, or did we need a full primer on high voltage? We also worried about recommending reuse of a TV tube (CRT) as a power supply, due to the dangers of capacitance discharge, and the unknown voltage and current. But even with a store-bought DC power supply, could the current of 0.4 milliamps be deadly? (Probably not.) Would the current-limiting knob protect makers? (Probably so.) Was the project too tempting for inexperienced teens? Isn’t it MAKE’s mission
to empower people to handle technology? And, having established an email thread of world-class makers questioning safety, what about legal liability?

Magazine spread. The article that almost was… We made a tough call. Tell us what you think at in the talkbacks

Mark Frauenfelder, editor-in-chief: Dear MAKE technical advisory board members: Attached is the layout for one of the projects in MAKE Volume 09 – a high-voltage “lifter.” The instructions call for a high-voltage DC power supply, but offer the alternative of using an old (pre-Energy Star) CRT monitor to supply the power:

Using an Old CRT as a Power Supply
Here’s how to adapt an old (pre-Energy Star) CRT monitor into a high-voltage power supply that’s adequate for a small lifter. Unplug the monitor and let it sit for at least an hour to allow residual charge to dissipate. Open up the monitor, and locate the large wire that leads to a rubber cup at the back of the tube. This wire supplies the tube’s electron gun. Lift up the cup and find a metal contact for the wire.

Run one insulated wire to the electron gun contact and another insulated wire to the metal spring framework that holds the CRT. These will feed the lifter’s emitter and the ground, respectively. Position the 2 wires as far apart as possible, close up the case, and you’re ready to go.

I’m a little concerned about these instructions because I’ve heard CRTs can hold powerful charges almost indefinitely. I guess you could drain the charge by shorting the leads with a screwdriver, but that makes a scary spark and noise.

What I’d like to know is (a) whether my concern is valid, (b) if it is, is there a safe way to dissipate the charge? and (c) is there anything else important that’s left out from this? Thanks for your help!

Too Much Juice from a CRT?

Charles Platt, technical advisory board: This is like asking me if it is a good idea for Wile E. Coyote, in a Road Runner cartoon, to mix gunpowder with birdseed – so long as he is veeery, veeery careful. My response: We cannot count on him to be quite careful enough.

I would not publish the CRT idea.

Reason 1: There is no guarantee that the capacitor inside a TV will discharge itself within an hour. Depends on the TV, depends on the circuit inside. Also, even if it is true, it depends on some young reader being willing to wait an hour. “Hey, look, it’s 15 minutes already, that should be long enough.”

Reason 2: Subsequently switching on the TV, after attaching wires to the high-voltage end, is a risk that I personally would not take. While I do not have the numbers, I strongly suspect that the high voltage inside the TV is backed with considerably more current-delivering capability than you need or want for a lifter. In other words, a TV is not like a Tesla coil which can harmlessly envelop you in very high voltage at negligible current. Everything I have read on this subject encourages me to think that a TV can kill you.

Reason 3: You are going to damage your credibility by suggesting this approach, because so many warnings against doing it have already been published elsewhere. It will be MAKE vs. the rest of the world, which is not a good position to put yourselves in unless you are absolutely sure of your facts (which apparently is not the case), ready to fight lawsuits, and eager for publicity.

I have no patience with the “Nanny State” and other entities that try to protect us from ourselves. Personally I have made explosives, have subjected myself to 240VAC numerous times, and have tried hang gliding and other risky activities. But for whatever reason, superstitious or otherwise, I would not poke around inside an old TV set.

Steve Lodefink, technical advisory board: From what I understand, the dangerous part of a CRT (the part that can kill you) is the shadow mask connector. This is connected to the side of the tube, also by a black suction “cup” looking thing. So, I can see a potential for someone mistaking that for the gun connector.

I hear that it is the shadow mask that causes the tube itself to become a huge capacitor. That is the part that can hold a charge for a long time, so we would want to warn against messing with that.

Tom Igoe, technical advisory board: My friend built a lifter a few years ago and wrote about it. He said he tried to use his CRT, and found that the current-limiting circuit stopped him because he couldn’t generate enough to get it off the ground before the CRT shut off the current. It was probably a post-Energy Star one. He ended up using a DC power supply he bought online, but he said the guys he interviewed swore by the CRT method, as long as you avoided the capacitance problem.

In any event, your hunch on capacitance discharge is right, I’ve chomped the ends off a few screwdrivers that way before, but never had to try it on a CRT. I’m a chicken, though, and not only used insulated drivers, but also wrapped the handle in a thick piece of rubber and wore rubber gloves. I’d never do it if I knew the possible amperage was over about 500mA, though, because theoretically a full amp will kill, and I have no desire to find out.

Shawn Connally, managing editor: We were, in fact, discussing the 1 amp (deadly) vs. 0.4 milliamp needed to fly the lifter (lots and lots less amperage), and were wondering if there was something else we could use. I guess the problem is the high voltage necessary. I will go warn the interns [Matthew Dalton and Jake McKenzie]. Now that I think of it, it has been very quiet in that room the last hour or so. Hopefully they haven’t fried themselves up!

Charles Platt: Interesting that your interns did the TV thing. I just went looking online and found that, allegedly, the tube carries up to 35,000 volts at only a couple of milliamperes. This is somewhat reassuring. On the other hand, further reading indicates that very high voltages may be dangerous because at high frequencies, the nervous system does not detect the electric input as pain, even though the current prefers flowing through the soft tissues and circulatory system rather than the skin, which has a higher resistance. So you may damage yourself without even knowing it … allegedly. (See the Wikipedia entry on Tesla.)

Add it all up, and who can say? May be safe, may not be safe.

Mister Jalopy, technical advisory board: The whole thing gives me an upset stomach. I won’t work on CRTs as I understand the charge lasts for weeks, not an hour. Wikipedia CRT entry backs that up. The other fellas know more than I do about this, but I wouldn’t attempt this project based on these instructions for anything.

I would pinpoint a power supply by specification (kV, A) and not give alternates. Otherwise people will be killing themselves with neon transformers. Let people Google if they want a cheaper (more dangerous) solution.

Charles Platt: High voltage just requires a suitable transformer. How about eBay? Search for “Tesla transformer” and you’ll find a bunch.

Frankly all of this stuff makes me nervous, even to the extent that I would not want to be the writer advising people on using it. I could easily see myself being named in the suit for negligence. And I don’t scare that easily.

My father, the chief engineer at a British automotive company, told me that at their testing lab, they had to use very high voltages. The employees had to stand on rubber mats, wear rubber gloves, and literally work with one hand tied behind their backs (to avoid the risk of a hand-to-hand heart-stopping jolt). If your readers had this much discipline, it would be no problem. But, I don’t think they do.

A childhood friend gave himself a 600V shock while wearing a pair of bedroom slippers. When he picked himself up off the floor, he found the slippers still where he had been standing in them, facing the workbench. He had literally jumped straight out of them!

I’ve seen too many near-fatal episodes. I have also seen, in an animal lab, how easy it is to stop an animal’s heart with nothing more than 110V AC straight out of a wall socket.

Big Blinky Flashing Skulls and Suicidal Tendencies

Joe Grand, technical advisory board: Yikes. In theory it sounds fine, but is very dangerous any way you look at it. You would definitely need to discharge the monitor with a screwdriver and not just let it sit for an hour. The CRT could also gather charge again over time (I think). I’m concerned that this article is oversimplifying the process and could seriously injure a large portion of our readers who aren’t properly trained in handling electronics like this. Even I am still overly cautious when working with monitors and usually discard them instead of trying to fix them. Just too risky. Maybe some of the other guys have suggestions to make this method safer, but to me it just sounds too risky to promote in a now mainstream magazine like MAKE (especially without some serious disclaimers, which still might not help to protect you or our readers). To me, high voltage and high current are extremely serious and should be treated with the utmost respect – that is, actually paying money for safe power supplies that have no (well, less, if used properly) risk of killing you.

David Pescovitz, editor at large: So if a good power supply solves the problem, why not just remove the CRT section entirely? When we mention that you need the power supply we could also tease that we’ll have other projects in future issues that require one. (Desktop Tesla coil?)

We could also mention that some people use a CRT as the power supply, directions to do so can be found online in various places, but that we think the risk outweighs the benefit and cost savings.

Phillip Torrone, senior editor: OK gang, here’s my opinion – this [CRT] sidebar without any doubt could kill someone in the procurement and in the operation if you screw up. We do a good job suggesting the DC power supply, let’s stick with that.

So – I’d kill the CRT portion of the print article, and on the [web] article page, link to the many articles online that show how to use and discharge CRTs. Online, we could always pull stuff if someone was stupid after seeking more info, and add big blinky flashing skulls that assure death if they’re not careful.

CRT Option Killed, Warnings Added

Shawn Connally: We have decided to take all the references to using a CRT out of the piece. We’ve also added a much sterner warning, actually two – one on the Materials page and one as a sidebar, “WARNING: When You Work with High Voltage.”

I’m really torn about this project after reading replies all day. I saw the interns working on this project for a couple of weeks and never thought a bit about it. They, of course, measure current at every step, but they never seemed too worried about it. They were actually more frustrated in how hard it was to get the lifter to float, than worried about working with high voltage. Ah, youth.

The author also doesn’t seem too worried about it, but was willing to rewrite bits and add the warnings. I’ll discuss more with Mark; should we not be running the piece at all? Should we put a big Editor’s Note at the beginning? It’s a tough call, especially late in the production process.

Unsafe at Any Amperage?

Tom Anderson, technical advisory board: Uncontrolled flight of metal objects at 20kV and unknown current. Hmm…

There is more than one way to die from high voltage. Electrocution is not the only problem. Getting hit with a high voltage causes a strong convulsion that “throws you across the room.”

It turns out that the power of our muscles is controlled by our nerves. Our muscles have more than enough strength to break our bones, but our nerves talk them out of it. The high-voltage hit will override your nervous system. Suddenly you can fly! (For a short distance, and landing is a bitch.)

The disposable camera flash in the flash kit [see MAKE Volume 04] also has high voltage, and the spark made a good picture. I have been hit by it multiple times (mostly because I was being stupid and didn’t short the capacitor). While it hurt like hell, I haven’t ever felt in danger for my life. On the other hand, the lifter project says “suicidal tendencies” to me, and at least calls for a level of sobriety that is, well, sobering.

I am also chicken about such things. Some years ago I worked with lethal voltages for about a year at work, and have the training for how to deal with it. I’m not seeing enough safety information in this article.

In the disposable camera hack, I took the direct hit multiple times and decided that it wasn’t too bad, and went on with the project. I wouldn’t recommend that anyone take the lifter hit to “see how it feels” with this project, because you might not live through it.

I can make a few recommendations to improve the safety of the design and to help people protect themselves from it, but I am hesitant to have anything to do with it, other than to say “No!” I don’t want to advocate cruelty or anything, but if you’re not willing to take the hit yourself, and you aren’t willing to test it on an animal, do you really want to test it on your readers?

The project (at least!) needs a ballast resistor to limit the current to decrease the electrocution risk. Also it needs a primer in high voltage safety. I’m really concerned about the safety of this one. Perhaps a better title would be “Unsafe At Any Altitude.”

Saul Griffith, technical advisory board: I’m with Tom, or perhaps I’m more conservative than Tom. I don’t think you should go anywhere near this one. There is no description of how much insulation you really should have on those wires, dielectric constant of air, and how you may not even have to touch the wires to get f***ed up.

This stuff is dangerous – Eric Wilhelm and I did a lot of 20kV electrostatic work at MIT and you could not possibly be careful enough with that stuff, we had the full rubber gloves and shoes and paranoia and still shook uncontrollably as we smelt the ozone and felt the charge in the air. I had a small shock myself that made me extremely wary of this stuff, probably a 5kV discharge.

The guys who designed these projects probably know enough to be really scared, and have worked with high voltage enough to be competent when scared. I just don’t think it’s worth the risk to instruct the general public. It’s not worth making a free speech issue out of a high-voltage project.

My technical advisor vote would be not to run the article, and I’m not exactly scared of dangerous things. I think it’s like running a “how to swallow a sword” article. Sure it can be done safely, but only if you’ve had a lifetime of training.

Shawn Connally: All the emails sent by the tech advisors have had a sobering effect on my thoughts. I am still inclined to leave the project in, and [art director] Daniel Carter and I have added 2 warnings, but I’m happy to have us scramble and replace it if that’s the decision we go with.

You might discuss with the interns as well; they say the monitor they used couldn’t hold a charge of more than 1.7 milliamps, I think it was. Basically, enough to give a nasty sting, but not kill.

Do Not Try This at Home, Kids

Dale Dougherty, publisher: Is there a way to change this from a project into an article that shows how the author did this but doesn’t characterize it as a DIY project? In other words, we can talk about how it’s done, and how strange it is, and even discuss the procedure for building it, without actually walking through the steps to do it as we do in a typical project.

We could even put some of this discussion of high voltage into the article and be up front that we planned to present it as something you could do yourself but despite it being cool, we don’t recommend that you do so.

Gareth Branwyn, technical advisory board: I can speak to the temptations of wanting to build such a project and not having years of experience. Reading over this piece, I think: “Cool. I want to build this!” Now, I’m an extraordinarily cautious person when it comes to being out of my depth technically, and especially around rogue electrons. So I might be okay attempting a project like this.

But I think of my teenage son who reads stuff in MAKE all the time and says: “I wanna build this!” (which goes right alongside other instant gratifications like: “I wanna get a PS3!” and “I wanna get an iPhone!”) This project is the kinda thing that would totally make him wanna. He would read all the cautions and try to take them to heart, but have no real sense of the dangers involved (he’s a teen; he’s invincible). I can imagine lots of teens wanting to try this project out and in some ways actually being “inspired” by the warnings in the piece.

It’s Not the Voltage, It’s the Power – Volts Jolt, But Mils Kill

Paul Spinrad, projects editor: Our Kirlian photography project [MAKE Volume 09] also uses a high-voltage power supply, although it’s more contained, rather than having wires strung around. Danger mainly comes from the power, not just voltage – a doorknob spark is high-voltage.

Here are the powers used in Lifter and Kirlian, compared to a stun gun, from an online description from a manufacturer:

Lifter: 20-25kV DC at 0.4 mA (DC) = 8-10 watts
Kirlian: 5kV at 1-5 mA (AC or DC) = 5-25 watts
Stun gun: 20-150kV at 3 mA = 60-450 watts (source: rkdefense.com/stunguninformation.php)

Although it’s also true that with the lifter, the voltage is way more out in the open.

It could also be true (I don’t know) that a human body has less resistance than the lifter, and would draw more current – but if you keep the amperage limit knob on the supply set to 0.5 milliamps, as the sidebar suggests, then the supply is supposed to shut off if anything draws more. Not that I’d want to test it myself…

Mark Frauenfelder: Well, I still think if we add dire warnings to this, we can keep it as a project. You are right, though, it’s all about the power. I’ve been shocked by an old spark coil (from an antique Ford Model T) which is high-voltage. It’s not fun, but it’s pretty harmless. Americanantigravity.com has been publishing lifter plans for years, and they have a nice safety guide. I think we should feel OK about running this if we include a warning like the one in their PDF:

Warning Notice: This document is intended for educational use only! The project described in this document uses extremely high-voltage power sources, and is intended for readers over 21 years of age who are experienced working with dangerously high-voltages. If you are not a legal adult, or are not proficient working with dangerously high-voltages, do not try to build this project without expert supervision. The author of this document is not responsible for any death, injury, or property damage resulting from or relating to the procedures shown or devices described in this document.

If we run this in red text right before the instructions, I think that’s a fair warning.

John MacNeill, author of Lifter article: As I understand it, the CRT has already been dropped from the article. But to answer your question, yes I have been shocked, and more than once. I’m not dead, but I cannot warrant that a similar shock wouldn’t put your heart into fibrillation (or interfere with a pacemaker).

Do you want to kill the article? There’s no doubt at all that misuse of high voltage can be lethal.

Mark Frauenfelder: Isn’t it the case that a high amount of power is what we should be concerned about, and not just high voltage?

Saul Griffith: At electrician school they teach you: “the volts just jolts, it’s the amps that clamps.” But electrocution and fires are stochastic. I’d still stand by care on this project.

Joe Grand, technical advisory board: Or “volts jolt, but mils kill” (mils as in milliamps). Even still, a high voltage at small current (possibly like the lifter) can still be extremely dangerous, especially to the untrained. It’s just not worth taking on that risk.

Shocks, Burns, and the Rough Landing

Tom Anderson: There is no standard output current for high voltage supplies, and nothing in the article tells you that more output current or power capability is more dangerous. Indeed, the article suggests that the design might be scaled up to build a vehicle! How is the maker supposed to know how to select or build a high voltage supply?

There are several safety problems: Current, voltage, and energy.

One of the worst shocks I ever experienced was from only 19V at 150kHz. I felt the aftereffects for days. I wasn’t being careful with it because I didn’t believe I would even be able to feel it, except with my tongue. [Editor’s note: Your tongue?]

It also depends on the capacitance of your load. The high-voltage supply may not kill you, but high-voltage supply with a load capacitor may kill you.

The other problem with voltage is “getting thrown across the room.” Plenty of opportunity there to land poorly. In my garage you would likely land on something that would hurt you. You can get thrown 10 feet (you actually throw yourself). Much of death by electricity is caused by landing, not the voltage itself.

What is the output capacitance on the high-voltage supply? If it holds more than a few joules it could cause severe burns. At 20 or more joules it could cause fibrillation. A defibrillator typically uses 120 to 200 joules. They design the electrodes (paddles) to mimimize burns.

E = 1/2*C*V2. You have a large voltage term (V) and it is squared. If you don’t know the capacitance (C), you don’t know what you are doing or how dangerous it is.

The fibrillation electrocution risk comes from current. 60Hz AC is worse than DC. Ground fault interrupters, which are designed to prevent electrocution, trip at 5mA.

The other electrocution risk is from power causing burns. This can happen at low voltage and high current, but is more common at high voltage. Three joules will give you a small burn that you will be able to feel the next day. You would get that from a 9W supply in a third of a second. If you manage to grab the high voltage and “stick” to it, you’ll be getting 9 joules per second until you get unstuck. (Watts are just joules per second.) Maybe not fatal, but it would probably change your attitude about electricity.

You have probably experienced a severe static electric shock of about 25kV. The capacitance of the human body is typically about 150pF, so 1/2*C*V2 comes out to 0.047 joules. A 300kV static electric shock (from, say, a Van de Graaff generator mishap) will get you about 7 joules.

Unlike whirling blades and hot coffee, most people don’t have an intuitive grasp of the danger of using high voltages or high currents. Nor do they have voltage, current, power, or joule meters that work in this range. I wouldn’t advocate working with a table saw while blindfolded. People who work with high voltage generally have some basic safety equipment, such as a way to measure high voltages safely, and a better way to discharge a capacitor than arc-welding a screwdriver across the terminals.

If there is interest, I will build a DC high-voltage power supply from a neon sign transformer and let you see it firsthand. Unlike in a neon sign, my DC supply would have an output capacitor that can store quite a few joules. I’ll turn it on at your place, though, OK?

Needed: A Safe Working Primer

Mister Jalopy: I think there is a common thread amongst most of the advisory board members:

* we have received some training on safe practices – even if it was anecdotal and casual
* we (or people we know) have gotten a nasty shock despite being careful
* we know this thing is scary – which would not necessarily stop us from doing it, but we would be damned careful

The problem is MAKE has never quantified what “damned careful” is. The article says follow high voltage precautions, but they are not detailed.

I would like to see a Safe Working Primer that would be an article and one-page cheat sheet that could be hung above your workbench. Maybe the cheat sheet could even run in every issue. Or a laminated or card-stock copy with a subscription. A free PDF permalink to the whole article would be a great benefit to makers for years to come.

I don’t know what constitutes dangerous voltage/amperage, so I just assume neon transformers, CRTs, and high-voltage car ignition systems are killers. Similarly, I am not qualified to say how dangerous this project is, but it sure looks scary with the high voltages and lack of insulation, not to mention the added dimension of the thing flying around. Without a detailed safe working section, it does not seem prudent to run.

Passivity vs. Empowerment – McDonald’s or MAKE?

Charles Platt: A lot of the speculation here can be clarified by checking standard reference sources. Wikipedia has a very good entry on electric shock, dealing with issues of amperage, voltage, frequency, and so on: en.wikipedia.org/wiki/Electric_shock

However, I think we’re missing the point by debating the specifics of electrical safety. This is just one instance of a much bigger, general dilemma that I would characterize as “Passivity vs. Empowerment.” On one hand, we live in a world where McDonald’s got sued, successfully, for serving coffee that scalded the thighs of a customer who spilled it. From this perspective, the only legally safe policy is to advise readers to be as passive as possible. They should never enter a workshop or pick up a power tool, let alone start poking around in consumer electronics products for fun.

On the other hand, as I understand it, the idealistically driven mission of MAKE (which I believe in very strongly) is to encourage readers to take control of technology, instead of being controlled by it. The magazine’s mandate is to advise readers to be as active as possible.

How do you reconcile this conflict? The dilemma is especially difficult since MAKE has positioned itself as a reassuring, upbeat publication that is friendly to the reader. To what extent does this friendly relationship entail protecting readers from themselves? If friends don’t let friends drive drunk, should friends encourage friends to play with electricity? These are questions that only my editors can answer!

Liability and the Nanny State

Bunnie Huang, technical advisory board: On the subject of passivity versus empowerment – I’m not a lawyer but I’ve been in a couple of legal scuffles now. I’d say that if someone was hurt executing the article, this thread itself is pretty damning evidence against MAKE for running the article. A panel of expert witnesses have essentially testified just now about their scars from playing with high voltages, and other stories they have heard about how dangerous and potentially
lethal something like this could be.

I’m a fan of empowerment, but I think to be fair you’d almost want to publish this thread along with the article, and let the reader know that a panel of the world’s best makers would exercise extreme caution (or not even do such a project) because of the risks involved.

In an ideal world, dangerous ideas are not self-censored – and that’s a core value of MAKE, I think. But I think there is an obligation to tell the whole story, which would include not only the dangerous idea itself, but the risks of the ideas and also what the experts think about those risks. This ultimately places the faith in the reader to decide appropriately on whether the idea is too dangerous for them. I think people should learn good safety techniques for high-voltage supplies, and a working knowledge of high-voltage supplies is very empowering, but very dangerous … just like many other technologies (munitions, cryptography … hah hah).

Probably the only caveat against this is if your demographic includes a readership that could be considered minors. If MAKE has a significant subscriber base of minors who are, at least in legal theory, unable to decide good from bad even when presented with the full monty, you may want to rethink things … I don’t know what the standards are surrounding the protection of non-adults, but I get the sense that the legal system has very little tolerance in that area.

William Gurstelle, technical advisory board: This is a question – about publishing information that could hurt, injure, or kill if misunderstood – that I’ve spent a long time considering.

Several years ago I published a book called Backyard Ballistics which explained, among other things, how to build a device that shoots projectiles at high velocities. Am I worried that someone might goof up and get hurt? Of course. Is that a reason not to publish information – that someone, anyone could make a mistake?

True story: a couple of years ago, a young adult in Texas built a spud gun and went out in the swamp. He spent all day collecting bullfrogs, tossing them down the barrel of his spud gun and shooting them into froggy goo on the other side of the swamp. But on the last occasion, his gun misfired. Against every warning and caveat possible, he looked down the barrel of the gun, and as you probably guessed, took a fair- sized bullfrog between the eyes with unfortunate results. (Google it for details.)

Point is, just because someone could make a mistake with the information you’re providing, it doesn’t mean the magazine is liable, morally or legally. Unless it’s incorrect. But if the info is correct, that is, it has been thoroughly vetted, can be clearly explained, and contains plenty of warnings of the magnitude of the consequences of error, well then, I say go for it. I don’t know the first thing about high-voltage power supplies, so I can’t tell how complete the MAKE explanation is, but if complete and thorough information can be provided, then go for it. Nanny State be damned.

Legal disclaimer: But as Dennis Miller says, that’s just my opinion; I could be wrong.

Mark Frauenfelder: This is all such interesting information and advice that I’m tempted to publish it in MAKE as a round-table discussion.

Thanks so much for offering your advice, Tom, and everyone else. We’ve decided not to run the lifter project (at least not in this issue).


Did we make the right call? What do you think?
Showing messages 1 through 9 of 9.

* Where would we be?

“Where would we be, if in the past we had spent more time
worrying about the temperature of coffee and bullfrog-firing spudguns? Would we have x-rays? Nylon? Space-flight, or even flight? Vaccinations? Now I am not suggesting that we should or can ignore these warnings from others. What I am suggesting is that forward-looking magazines like Make tackle this issue head-on and find a way to publish articles such as this, with appropriate warnings and disclaimers to protect both the reader and the magazine. I think this is a much larger issue than the technical details of this specific quashed article. Thank you for raising it for discussion by your readership. I believe it reflects an ethos that could help pave a way out of this type of mess.”

Posted by BigNut on March 17, 2007 at 10:02:27 Pacific Time

* ion-driven lifter

“this device was constructed and demonstrated on MythBusters.”

Posted by GregKr on March 16, 2007 at 21:01:38 Pacific Time

* Hazard issues similar to tesla coils…

“The amateur chemistry and Tesla Coiler communities have been dealing with lethally dangerous projects for decades. For this kind of advanced-level hobby project, the “barriers to entry” against young children and total newbies take the form of 1. expensive and/or hard-to-obtain parts and chemicals, 2. difficult instructions (it’s an advanced project, after all,) as well as 3. repeated serious warnings about the danger. Only thing is… these projects aren’t inherently difficult. To prevent problems, responsible authors will not only make very clear that the dangerous projects are for advanced hobbyists only, but also they’ll avoid removing the number one barrier. For example, they won’t give formulas for simple explosives using common art supplies, or Tesla Coil plans using easily modified television sets or microwave ovens. I doubt that the Lifter article would attract a lawsuit as long as sufficient warnings were given, and as long as the article *lacked* simple detailed instructions easily followed by anyone. If they have to ask questions, then they don’t have the skills needed. (And if they insist on getting hurt, well, any number of dangerous project plans are instantly available on the internet.)”

Posted by wbeaty on March 16, 2007 at 18:03:44 Pacific Time

* Glad to see this kind of discussion

“As someone who has written about Wi-Fi for years, in which high-gain antennas seem to be used as toys by some hobbyists and even professionals, I’m so pleased to see a discussion among experts – people who know the risks involved. It’s great. (On the side of telling people about safety, perhaps a Make piece called What Can Kill You Or At Least Won’t Make You Stronger would be helpful, including standing in front of multi-watt EIRP Wi-Fi dishes.) I note that Charles Platt spreads an old trope, much like “Al Gore invented the Internet”: “On one hand, we live in a world where McDonald’s got sued, successfully, for serving coffee that scalded the thighs of a customer who spilled it.” McDonald’s was actually making coffee at a temperature far too hot for human consumption. Numerous articles documented that McDonald’s boost the heat far above (in one report, 20 degrees hotter) than most of its competition. I only bring this up because the McDonald’s lawsuit wasn’t frivolous–it was part of a pattern of disregarding a serious problem that the company was allegedly well aware of. This kind of groupthink or negligence or whatever it was is clearly NOT being exhibited at Make.”

Posted by eggboard on March 16, 2007 at 14:50:06 Pacific Time

* Good call

“Playing with flyback transformers and CRTs is best left to professionals (or at least hobbyists with experience in high-voltage power supplies and circuits). I’ve hooked up a simple circuit using a high-voltage flyback transformer from a CRT (http://www.semifluid.com/?p=34) and found that it can easily melt the anode and cathode leads. There is no current regulation in the flyback transformer, but instead it appears to be proportional to driving voltage and correlated with the driving frequency. In my humble opinion, it was wise not to publish the article from a liability standpoint, but none-the-less it would be a very interesting read.”

Posted by special4k4 on March 16, 2007 at 14:45:10 Pacific Time

Good call (maybe not.)

“Flipping through Volume 9 (I’m a loyal subscriber!), I
noticed the following in the materials section for the Kirlian Digital Photography: “High-voltage power supply: You can use a Tesla coil, induction coil circuit, high-voltage flyback transformer circuit, or any other source that puts out 5,000+ volts, between 1-5 milliamps, at any frequency (or DC).” (emphasis mine) The article then goes on to suggest: “Shooting people: Sooner or later you are going to want to shoot people. The best place to start is the person’s fingertip…” (again, emphasis mine) I then must ask, where was the editorial review when this article was published? It seems more dangerous (higher current power supplies suggested, few warnings other than “make sure the subject doesn’t touch ground”, and suggestions to directly connect the HV power supply to bare skin). If anything, the levitator article seemed like it would have recommended safer experimental procedures with the current-limiting ballast resistor. Seems as though the above discussion on the levitator never happened for the Kirlian Digital Photography article. Any explanation?”

Posted by special4k4 on March 16, 2007 at 15:49:30 Pacific Time

+ Good call (maybe not.)

“You can make the power source for Krilian photography without taking apart a CRT, I suspect. Plenty o’ folks have done 5kV at 20mA with no ill effects. I’ve done it by accident myself. I suspect getting zapped by the lifter wouldn’t be that bad. But if you take apart a CRT to build a lifter power supply, you start dealing with capacitors. The big problem is that the email thread is too damaging a record, I suspect. It would be subopaenaed and come back to bite them were a lawsuit to be filed.”

Posted by wirehead_arts on March 16, 2007 at 16:06:36 Pacific Time

# Good call (maybe not.)

“Naturally, we must always protect everyone from themselves. What fool would think that technically-minded people could make decisions for themselves and to determine their own limits? Why not place everyone in stasis, ensuring our safety for all time? I could possibly agree with em on the liability issue, but that’s not a problem with the technology or the source so much as the overabundance of professional victims out there with a lawyer on speed dial.”

Posted by velojym on March 16, 2007 at 21:44:30 Pacific Time

* Good call (maybe not.)

“The problem is that even though most “technically-minded people could make decisions for themselves and to determine their own limits”, the publishers could not assume that all “technically-minded people” will make wise decisions. Given that all of the technical advisors are “technically-minded people,” it was clear that not all of them were aware of the dangers of HV power supplies and did not know their limits and what precautions should be taken. I still believe that the project should be constructed under the supervision / guidance of other individual(s) with experience in HV electronics; however, in retrospect, I agree that information wants to be free and that it is important to disseminate it to encourage hobbyists to learn, experiment, and have fun. As I say on my site, safety is the primary concern when working with high voltage circuits. Always be careful, use extreme caution with high voltage circuits, and play it safe! My questions then is why they axed the safer article (IMHO) and chose to publish the one that recommends connecting a HV supply directly to an individual’s skin for long exposure digital photos. I would like to know what the decision process was to publish one while cutting the other.”

Posted by special4k4 on March 17, 2007 at 10:14:31 Pacific Time

Leave a Reply