Should I build a Tesla coil for a science fair? | Hacker News Reader

Should I build a Tesla coil for a science fair?

teslacoildesign.com

42 pointsbelter32 comments

Building a fire death machine using soviet military tech

https://www.youtube.com/watch?v=UNisqZOAaAs

I was literally watching this video an hour ago. This guy is nuts but he does make sure to mention safety in every video. Because of him I will never be unsafe with lasers because I don't want to go blind forever.

And then you have zilipoper

My favorite laser safety poster, seen in a high-power laser lab:

"WARNING: Do not stare into laser with remaining eye."

There was, of course, a full set official warning posters as well. But that's the one I remember.

That video was incredibly inspiring. Time to dig out the spare chicken wire.

Did anyone else catch the response to this FAQ ?

> Can I harvest free energy or power an "off the grid" electrical system with a Tesla coil?

> Many people have realized our fiat monetary system and corrupt political leadership will likely lead to increased financial and political disorder - and possible electrical outages and price increases. I'm often asked if a Tesla coil can be used to generate or gather power. No, a Tesla coil cannot harvest free energy, ambient energy ...

Capacitors aren't to be fooled with.

Back in the tube TV times, I knew some guy working at a TV shop who shot off half a thumb, because he touched a loaded capacitor in a TV that was just unplugged.

Don't underestimate the power of every day appliences.

Even the capacitor inside a disposable camera (for the flash) is no joke. Used to mess around shocking ourselves with that when we were kids

I once shorted out one of those through my thumb and I swear I felt the ghostly presence of my dead brother even though my brother is alive and was at work at the time.

Getting a few dozen volts straight through a nerve will make you feel weird things.

When I was a child I was trying to take one apart by prying with a screwdriver. I accidentally shorted the switch that started the flash with my screwdriver. I heard the capacitor charge, but stupidly didn't back away slowly and kept prying. I got zapped through the screwdriver, and I involuntarily threw the camera all the way across the room.

I also nearly killed myself with a giant DIY laden jar I thought was discharged. It was not. I discharged it across my arms (eg, across my heart). Luckily there was very little stored power, it hurt enough to give me pause but I wasn't injured. This thing was pretty big though, it definitely could've held enough power to hurt me badly.

Lessons learned!

We did this too! Homemade "tasers" from a disassembled disposable camera. Enough to zap an older brother and run for your life, but not enough to hurt anyone. Good times.

To be fair a CRT is possibly the most lethal piece of consumer electronics ever made. It can kill you even after sitting unplugged for months.

How far away are you planning to put the warning signs, for people with implanted medical devices (cardioverter-defibrillators and such), who might be endangered by your Tesla coil?

If it turns out that those warning signs weren't far enough back, who's carrying the multi-million-dollar liability insurance policy?

How sensitive are such devices to stray EMI? Those people would be at risk from all sorts of everyday emitters such as welders, motors with skipping brushes, vehicle ignitions, radio transmitters, etc. If this was the case, they'd need to stay home in a shielded room.

Well...an electrical engineer friend of mine, who recently had such a device implanted, told me that he's giving away his welder - because he can no longer use or be near it. No mention of dumping his microwave oven, nor cell phone, nor... Evidently the power, frequency distribution, etc. of the EMI (from the latter items) is sufficiently weak or off-frequency to ignore.

Further down, user porlune notes that one publicly-displayed Tesla coil is enclosed in what appears to be a Faraday cage. There may be liability and visitor safety reasons for that.

The article says you absolutely shouldn't build one for a science fair, and calls out the risk to disrupting pacemakers and such as a principal reason why.

Some buddies and I built a Tesla Coil for a physics class project. The huge homebrew capacitor bank made of snapple bottles, and a microwave flyback transformer made the futzing with the base of it way more dangerous than the 20-40 kV arcs you got off the top.

Turned out the thing worked pretty well as an AM radio jammer, too.

Tesla coils playing Africa by Toto: https://www.youtube.com/watch?v=fstnVzw7Vbw

you can also end up generating x-rays with certain bulbs containing a vacuum

and open sparks generate quite a lot of UV too

You've never seen a giant Tesla coil in operation have you? Believe me when you do you'll understand that you can absolutely not put such things into a public space like a science fair. They are very scary and definitely lethal.

Oh dude the old Frys electronics in Fremont California had some on display they would randomly discharge when you were browsing around the store it was awesome.

https://www.youtube.com/watch?v=AUOuu34TqF8

I remember that thing, but it was in a big faraday cage to prevent anyone from getting zapped.

There was also the building height Jacob's ladder over by the PC system builders section.

Had the pleasure of experiencing that and much more, like having thousands of volts through my hand, at the Nikola Tesla Museum in Belgrade. Highly recommended.

Arc Attack is kind of fun too - https://www.youtube.com/user/arcattackmusic

The public space aspect is also a "you need to stand back this far"

Note the suit that the person is wearing in the Derezzed video - https://youtu.be/psoLXEBmfRg

Also note the grounding fences around the area.

The video with them and Tested gets into the tech of it - https://youtu.be/4m6EjnEYEEg

Small one... ok. Big one? Nope.

The power of the Dark Side...https://youtu.be/rd3bH_xNYYQ?t=65

If you know what you're doing they're not lethal at all. Low duty cycle combined with smaller size and they're absolutely science fair material. There's plenty of videos of people sticking their hand right into the path of one at low duty cycle.

Or simply put it inside metal wire cage and don't let people run it when you're not around.

There is a Tesla coil on public display at the Griffith Observatory, though it is protected by what looks like a Faraday cage (and glass).

https://www.youtube.com/watch?v=tlTlnbRG6kA

I've done this. I won second place at the county level, behind someone who built a dot-matrix printer, and also got a medal from the US Army. Was it safe? No. But it was the late 1970s when things were "looser".

I was able to cause a 4' long fluorescent bulb to light up at 15 feet away. And destroyed TV & radio reception for the neighbors while it was running. Being a big fan of Nikola Tesla at the time, my experiment was measuring the wireless delivery of power using an AC voltmeter at various distances. But mostly I built it because it was cool.

I used a 15kv neon sign transformer. The capacitor was made from two copper sheets glued to opposite sides of some picture frame glass, which was epoxied into a wooden frame (no metal fasteners allowed!). The spark gap was two threaded rods on a plastic frame so that I could adjust the frequency. The primary coil was bulk sparkplug wire. The secondary was two spools of magnet wire laid down on a 6" diameter PVC drain pipe, with several coats of lacquer sprayed over it (that gave me pneumonia from the fumes). I went through about 3 capacitors before I got a good one because the glass would crack in the family oven when I cured the epoxy.

>Should I build a Tesla coil for a science fair?

>mostly I built it because it was cool.

I would say build it because you want it, then it'll be a science fair every time you run it.

In 6th grade we built one on a portable cart which was brought into class on project days until it was complete.

Ended up with a 6 foot tall coil topped with a classic copper flush toilet float. It would throw sparks a few feet to the closest fluorescent tube a kid was holding up.

I highly recommend visiting the Museum of Science in Boston and attending a lightning show. https://www.mos.org/live-presentations/lightning

The lightning show (with Tesla coils) is absolutely wonderful.

I haven't been to the Boston science museum is probably 20 years. It's nice to hear they're still running that exhibit.

A fun tidbit about the giant Van de Graaff generators they have was that they were built by Robert Van De Graaff himself as part of early linear particle accelerator experiments.

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