Safe high voltage generator for an arc lighter?

Thread Starter

-live wire-

Joined Dec 22, 2017
959
I go camping every year in Vermont. I use a traditional lighter for the camp fire. But inevitably it will run out of lighter fluid and I will have to buy another one, or more lighter fluid. The cost will add up. However, I have heard of these arc lighters that use high voltage arcs to ignite things. It would be a good experience to make one and the electric version would have many advantages. It could last me many years if I use a rechargeable battery for it and design a good circuit. I also may want a HV generator for a demonstration jacob's ladder or something like that.

But I am concerned about safety. I either want it to be limited to less than 5 mAs or for it to be in very short pulses so that it is not too much worse than static discharge. I am okay with the risk of burns, but not of fatal electrocution. I also do not want excessive UV or other damaging particles emitted. I understand many of the circuits used, but do not know too much about what is required for arcs. I know you need a certain voltage for a certain distance, but I do not know too much about the current requirements.

So is it possible to design a circuit that will get continuous arcs (not just one when you initially press a button or release it) and not have the dangers I mentioned? I also want the biggest arcs possible for something that is portable and safe enough. More voltage (hypothetically) means more current limits and bigger arcs, which would both be good. I want it to arc across at least 1/2 an inch, so that means 10-15kV with dry air.

This is my idea for one that has very short pulses. I am not sure if it is practical though. As a bonus, it should have a long battery life. A capacitor gets charged by a 9V rechargeable battery (I have a few lying around). It gets charged very slowly through a high value resistor. It should take about 200mS so that it is only short bursts. Then it quickly discharges through a HV transformer after it gets to a certain voltage. There is a schmitt trigger that is high if it is above 7-8V and low if it gets below .5V. This way it starts discharging at 7-8V and stops at .5V. Then it gets slowly charged again. It should cause inductive spiking in the primary and even bigger voltages in the secondary. I am not sure how to get that spiking without the risk of damaging the components though. Any ideas? Or maybe another circuit that can get HV, pulsed or continuous? And would I be able to simply add a megaohm resistor in series to limit the current but still get the same arcs? Also, how long can you handle a few amps? Is it 1-2uS or 1-2mS, or somewhere in between? This would be important in designing it to be safe enough. And what about a few uS but multiple times per second?

I used this online calculator to find out the time it would take to charge and discharge a cap through different loads. It should help me find the right R and C.
http://mustcalculate.com/electronic...arge.php?vfrom=0&vto=7.5&vs=9&c=20u&time=200m
http://mustcalculate.com/electronic...ischarge.php?vfrom=7.5&vto=.6&vs=0&c=20u&r=.4
 

ian field

Joined Oct 27, 2012
6,536
I go camping every year in Vermont. I use a traditional lighter for the camp fire. But inevitably it will run out of lighter fluid and I will have to buy another one, or more lighter fluid. The cost will add up. However, I have heard of these arc lighters that use high voltage arcs to ignite things. It would be a good experience to make one and the electric version would have many advantages. It could last me many years if I use a rechargeable battery for it and design a good circuit. I also may want a HV generator for a demonstration jacob's ladder or something like that.

But I am concerned about safety. I either want it to be limited to less than 5 mAs or for it to be in very short pulses so that it is not too much worse than static discharge. I am okay with the risk of burns, but not of fatal electrocution. I also do not want excessive UV or other damaging particles emitted. I understand many of the circuits used, but do not know too much about what is required for arcs. I know you need a certain voltage for a certain distance, but I do not know too much about the current requirements.

So is it possible to design a circuit that will get continuous arcs (not just one when you initially press a button or release it) and not have the dangers I mentioned? I also want the biggest arcs possible for something that is portable and safe enough. More voltage (hypothetically) means more current limits and bigger arcs, which would both be good. I want it to arc across at least 1/2 an inch, so that means 10-15kV with dry air.

This is my idea for one that has very short pulses. I am not sure if it is practical though. As a bonus, it should have a long battery life. A capacitor gets charged by a 9V rechargeable battery (I have a few lying around). It gets charged very slowly through a high value resistor. It should take about 200mS so that it is only short bursts. Then it quickly discharges through a HV transformer after it gets to a certain voltage. There is a schmitt trigger that is high if it is above 7-8V and low if it gets below .5V. This way it starts discharging at 7-8V and stops at .5V. Then it gets slowly charged again. It should cause inductive spiking in the primary and even bigger voltages in the secondary. I am not sure how to get that spiking without the risk of damaging the components though. Any ideas? Or maybe another circuit that can get HV, pulsed or continuous? And would I be able to simply add a megaohm resistor in series to limit the current but still get the same arcs? Also, how long can you handle a few amps? Is it 1-2uS or 1-2mS, or somewhere in between? This would be important in designing it to be safe enough. And what about a few uS but multiple times per second?

I used this online calculator to find out the time it would take to charge and discharge a cap through different loads. It should help me find the right R and C.
http://mustcalculate.com/electronic...arge.php?vfrom=0&vto=7.5&vs=9&c=20u&time=200m
http://mustcalculate.com/electronic...ischarge.php?vfrom=7.5&vto=.6&vs=0&c=20u&r=.4
Some disposable cigarette lighters have a percussion piezo spark generator - I routinely use an empty lighter to spark various blowtorches.

The chopper transformer from a set top box run backwards can set fire to things with a blocking oscillator running from a 4.8V Ni-Cd pack.
 

Reloadron

Joined Jan 15, 2015
7,501
I don't think you will find a simple solution for starting a fire using a high voltage arc. I am sure you have seen currently marketed "stun gun" arcs. Even those will not easily start a fire when applied to combustible materials. The problem seems to be the actual arc is not hot enough. Yes, my wife buys those little fire sticks for lighting the grill but in that case a small arc is used to ignite butane gas which in turn creates a flame to light the grill. To actually ignite a solid like a piece of paper would require a hotter spark than you can easily generate. That being the problem. Igniting a gas is not a problem but igniting a combustible solid like a piece of paper would require an arc of significant heat.

Disposable butane lighters are inexpensive and taking a few each camping trip they should last a few years unless you plan to be starting quite a few fires daily. I do not see a simpler less costly alternative.

I even tried igniting gun powder (both smokeless propellant and black powder) using assorted high voltage sparks much like as seen in this video and my own results were about like the video. To get the heat you need a high current arc which involves a larger power source than you want to drag around. My money is on a cheap Bic lighter. :)


Ron
 

ian field

Joined Oct 27, 2012
6,536
I don't think you will find a simple solution for starting a fire using a high voltage arc. I am sure you have seen currently marketed "stun gun" arcs. Even those will not easily start a fire when applied to combustible materials. The problem seems to be the actual arc is not hot enough. Yes, my wife buys those little fire sticks for lighting the grill but in that case a small arc is used to ignite butane gas which in turn creates a flame to light the grill. To actually ignite a solid like a piece of paper would require a hotter spark than you can easily generate. That being the problem. Igniting a gas is not a problem but igniting a combustible solid like a piece of paper would require an arc of significant heat.

Disposable butane lighters are inexpensive and taking a few each camping trip they should last a few years unless you plan to be starting quite a few fires daily. I do not see a simpler less costly alternative.

I even tried igniting gun powder (both smokeless propellant and black powder) using assorted high voltage sparks much like as seen in this video and my own results were about like the video. To get the heat you need a high current arc which involves a larger power source than you want to drag around. My money is on a cheap Bic lighter. :)


Ron
the 15,625kHz flyback system in UK TVs were the impetus behind safety systems that made servicing a total nightmare. It could set fire to things that don't want to burn.
 

BR-549

Joined Sep 22, 2013
4,928
They call those plasma lighters windproof.....but staying lit and alighting are different.....a whole different context with a zippo. But the plasma lighter can light small dry kindling in calm air.

Bic has a nice long self life, simple and cheap....and a real flame.
 

Hymie

Joined Mar 30, 2018
1,277
Here are some ebay items that might be of interest.

https://www.ebay.co.uk/itm/HV-1-Hig...517280?hash=item3d4b8cb3a0:g:N3EAAOSw2vVZ4C~e

https://www.ebay.co.uk/itm/DC3-6V-6...257682?hash=item56a68a20d2:g:72AAAOSwR2RaJ6iT

https://www.ebay.co.uk/itm/3-1000KV...hash=item3afe6508f7:m:mMVk1ISjKR3cjHCTfUl3G_Q

https://www.ebay.co.uk/itm/DC-6V-12...465749?hash=item33d4611ad5:g:TuwAAOSwnSxZiY0Q

They have the advantage of being potted to avoid moisture getting at the high voltage circuitry – but they appear to need more current than can be supplied by a standard PP3 battery, but a suitable lithium-ion battery source might suffice.
 

MisterBill2

Joined Jan 23, 2018
18,176
The problem, as has been mentioned a bit, is not about the high temperature but it is the quantity of heat energy delivered. Those short pulses do not contain enough energy to ignite most solid materials reliably. A simple sparker could reliably ignite some gasoline poured on the tinder, and a pint of gas used that way could last a few weeks, so if you chose to use that method it may be adequate. BUT you would need to practice with it before heading out on your trip. You could use one of those piezo-electric sparkers for that sort of arrangement, if you built up a reliable and stable spark gap.
Adding a series resistor to the spark system would certainly reduce the chance of starting a fire, so it will not help at all. To reliably start any sort of fire you really do need a fairly constant spark that has a bit of current. With a suitable step-up transformer you could use a hand-cranked magneto, such as from an old military field phone, to generate a constant spark. And as long as your system was hand-operated getting electrocuted is not at all likely since you would stop at the first feeling of a shock. At least most folks would.
 

Reloadron

Joined Jan 15, 2015
7,501
Thinking about this a little more, if we considered building something like this just how water resistant would it need to be? Not water proof but even just water resistant?

The standard size Bic lighter has 4.5 grams of butane fuel plus a little extra 0.01 to 0.04 grams. Factory fresh it weighs in at around 21.75 grains. While difficult to nail down an average Bic lighter has about an hours worth of burn time so if we figure what? Maybe 15 seconds if that to light a fire I can light about 240 fires on a single Bic. I can buy Bic Classic Disposable Lighter, Colors May Vary 1 ea (Pack of 6) on Amazon for about $1.35 each which can light about 1,400 fires easily. While out in the wilderness if I drop one in a cold stream I simply fish it out and shake it off and blow any water off the flint and the things will light. Those Zippos I carried over many years wouldn't even do that. No batteries to charge or batteries to go dead at the wrong time.

While the
Rechargeable Electric Plasma Lighters Single and Dual Arc even store bought are a pretty cool novelty I do not see a build or buy device like this as cost effective or practical for camping once a year. :) You can even buy a cool waterproof case for a plane Jane Bic.

Ron
 

DNA Robotics

Joined Jun 13, 2014
647
A Pocket Tazer Stun Gun, a great gift for the wife... A guy who purchased his lovely wife a pocket Tazer for their anniversary submitted this:

Last weekend I saw something at Larry's Pistol & Pawn Shop that sparked my interest...
The occasion was our 15th anniversary and I was looking for a little something extra for my wife Julie. What I came across was a 100,000-volt, pocket/purse- sized tazer.

The effects of the tazer were supposed to be short lived, with no long-term adverse affect on your assailant, allowing her adequate time to retreat to safety....??

WAY TOO COOL! Long story short, I bought the device and brought it home.
loaded two AAA batteries in the darn thing and pushed the button.
Nothing! I was disappointed. I learned, however, that if I pushed the button and pressed it against a metal surface at the same time, I'd get the blue arc of electricity darting back and forth between the prongs.

AWESOME!!!

Unfortunately, I have
yet to explain to Julie what that burn spot is on the face of her microwave.

Okay, so I was home alone with this new toy, thinking to myself that it couldn't be all that bad with only two AAA batteries, right?

There I sat in my recliner, my cat Gracie looking on intently (trusting little soul)while I was reading the directions and thinking that I really needed to try this thing out on a flesh & blood moving target.

I must admit I thought about zapping Gracie (for a fraction of a second) and then thought better of it. She is such a sweet cat. But, if I was going to give this thing to my wife to protect herself against a mugger, I did want some assurance that it would work as advertised. Am I wrong?

So, there I sat in a pair of shorts and a tank top with my reading glasses perched delicately on the bridge of my nose, directions in one hand, and tazer in another.

The directions said that a one-second burst would shock and disorient your assailant; a two-second burst was supposed to cause muscle spasms and a major loss of bodily control; and a three-second burst would purportedly make your assailant flop on the ground like a fish out of water. Any burst longer than three seconds would be wasting the batteries.

All the while I'm looking at this little device measuring about 5"
long, less than 3/4 inch in circumference (loaded with two itsy, bitsy AAA batteries); pretty cute really, and thinking to myself, 'no possible way!'

What happened next is almost beyond description, but I'll do my best ...

I'm sitting there alone, Gracie looking on with her head cocked to one side so as to say, 'Don't do it stupid,' reasoning that a one second burst from such a tiny lil ole thing couldn't hurt all that bad. I decided to give myself a one second burst just for heck of it. I touched the prongs to my naked thigh, pushed the button, and ...

HOLY MOTHER OF.. . WEAPONS OF MASS DESTRUCTION . . . WHAT THE ....!!!

I'm pretty sure Hulk Hogan ran in through the side door, picked me up in the recliner, then body slammed us both on the carpet, over and over and over again. I vaguely recall waking up on my side in the fetal position, with tears in my eyes, body soaking wet, both nipples on fire, testicles nowhere to be found, with my left arm tucked under my body in the oddest position, and tingling in my legs!

The cat was making meowing sounds I had never heard before, clinging to a picture frame hanging above the fireplace, obviously in an attempt to avoid getting slammed by my body flopping all over the living room.

Note: If you ever feel compelled to 'mug' yourself with a tazer, one note of caution: there is NO such thing as a one second burst when you zap yourself! You will not let go of that thing until it is dislodged from your hand by a violent thrashing about on the floor! A three second burst would be considered conservative!

A minute or so later (I can't be sure, as time was a relative thing at that point), I collected my wits (what little I had left), sat up and surveyed the landscape.

My bent reading glasses were on the mantel of the fireplace. The recliner was upside down and about 8 feet or so from where it originally was. My triceps, right thigh and both nipples were still twitching. My face felt like it had been shot up with Novocain, and my bottom lip weighed 88 lbs.. I had no control over the drooling.

Apparently I had crapped in my shorts, but was too numb to know for sure, and my sense of smell was gone. I saw a faint smoke cloud above my head, which I believe came from my hair. I'm still looking for my testicles and I'm offering a significant reward for their safe return!

P.s... My wife can't stop laughing about my experience, loved the gift and now regularly threatens me with it!

If you think education is difficult, try being stupid !!!
 
I dunno, seems like a tech solution that isn't needed.
Why not the old fine steel wool and a battery. Works when wet, and does use electricity, so is not as cavemanish as flint...
 

MisterBill2

Joined Jan 23, 2018
18,176
Oh Wow!!! Quite an adventure, and still it might not be enough heat energy to start a fire. Of course the fact is that the person holding the device is also part of the circuit. I doubt that it was anywhere near 100,000 volts, because that much can jump several inches with no provocation. But even a few hundred volts with a fast rise time can be painful and very startling.
I am inclined to agree that a package of lighters would be a much more effective approach, and a lot safer. But not just one, rather a pack, because they have been known to leak all the fuel, or to lose the flint, or have the spring fail. I have suffered all 3 kinds of failures over the years. A Zippo, with a spare flint stuck into the bottom of the cotton wad, ans fueled with a spoon full of av gas, is good for about two days of riding in a BDU pocket in the jungle. Not good enough for a week of camping.
 

Thread Starter

-live wire-

Joined Dec 22, 2017
959
I still want to make an arc lighter because it would be a good experience. And it could probably ignite a piece of paper or something like that. I want to actually make it, not just buy some commercial product. I want it to get continuous arcs, not just when you press or release a button.

So when you say a small auto transformer, how small do you mean, maxheadroom? It should be roughly pocket sized. And is my idea of slowly charging and quickly discharging a cap through a transformer good? Will it get the inductive spiking, and how would I avoid damaging the components with those spikes? Would zeners be enough? And could I use a capacitor with an ultra low ESR to get much more power? My understanding is that the inductor will want to continue to push the same amount of current through it. So it momentarily increases the voltage to do that. And more current means more voltage.

So I've done some more thinking on the components I am going to use. I will use a boost converter (I ordered a few, they should be getting here soon) to step the voltage up to 30VDC from one or two 9V batteries. Then this charges a low ESR 10mF capacitor to 28ishV. Then a schmitt trigger IC (with normal and inverted outputs) turns an IGBT or mosfet (depending on the voltages) on that discharges it through the coil till it is down to 20V. The inverted output goes to an IGBT or fet that controls the charging of the capacitor. It charges when it gets below 20V, and turns it off when it is above 28V. This way the boost converter does not try to power the coil. I will add 40V zeners or something to the boost converter, the transistors, and the capacitor/scmitt trigger. This should hypothetically get some continuous oscilation and pulses of power.
http://mustcalculate.com/electronic...ischarge.php?vfrom=20&vto=28&vs=30&c=10m&r=10
http://mustcalculate.com/electronic...ischarge.php?vfrom=28&vto=20&vs=0&c=10m&r=.25

So suggestions for specific components I could use? I am looking to get most of them on amazon or mouser. Do I need the IGBTs to handle the voltages, or would zeners and fets be good? Because IGBTs are often a lot less efficient, and I would really prefer fets. Any modifications I should make? And I do not have a simulator to simulate a circuit like this. So can someone else run a simulation or suggest a good free simulator? One last thing. How do I prevent this from supplying lethal amounts of power? Would it generate the HV for long enough to kill you? Thanks,

-live wire-
 

Thread Starter

-live wire-

Joined Dec 22, 2017
959
How is that one wired? Is it just one primary and one secondary, is there flyback, or what? And what is a typical DC resistance for the primary?
 
Top