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Handheld Tesla Coil prototype

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LAN_403

Conundrum

Tue Feb 14 2017, 06:13AM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

Hi, is something like this actually feasible?

I had some ideas, shared them with a couple of Ebay sellers to see if they were interested and there are several applications
for a high frequency low current RF induction device like this such as: testing small gas tubes, "stress" testing PCs for EMI immunity,
induction heating, etc and the relatively confined field thanks to the new secondary design makes it possible to modulate the output
independently on each coil.

Its not intended to be hazardous and in fact could be very useful as the prototype other researchers have made can induce a field
over several metres thanks to modifications made possible by laser advances and 3-D printing.

I also have some ideas to use existing technology in order to boost efficiency by an order of magnitude, my (probably inaccurate)
calculations suggest that it could run for 25-30 seconds at a time or until the driver stages heat up and between the poles
generate nearly 500,000 volts (0.5MV) of RF at 13.56 MHz while being not much larger than a TV remote control!

Its not actually that hard, just requires some creative thinking to build it.
The tricky part now would be building a test coil before spending probably 2 weeks making the full scale version
(see later comment about PCB coil design and testing)
there are a lot of very complex optimizations requiring FEMM and fine tuning of the field coil(s) and secondaries.
RF SWR feedback and dual magnetometers would help at least for proximity effects correction and feedback to prevent
detuning (noticed thread mentioning loss of ZVS as a cause of expensive MOSFET damage)

Any ideas?
-A

(just realised, don't actually need the CSAC as a conventional magnetometer is sensitive enough. it was actually to use
this for another project and has nothing to do with the handheld TC.)

Enceladus

Sun Feb 19 2017, 05:53AM

Registered Member #61428 Joined: Sat Jan 14 2017, 12:39PM
Location:
Posts: 50

Certainly, it's feasible. In fact, it's been done.

I don't know if the youtube videos I post work for others, but they never work when I preview my post. If the video fails to load you will have to manually search for:

Handheld TESLA COIL GUN at 28,000fps - Smarter Every Day 162

Seems like a TC operating at 13.56 MHz would be a strange finicky beast. Did you just choose that frequency because it's an ISM band? I would expect it to cause more dielectric heating than dielectric breakdown in the surrounding air. But what to I know. Have you built a bench top version already? Is there actually a practical limit on TC frequency?

DerAlbi

Sun Feb 19 2017, 09:46AM

Registered Member #2906 Joined: Sun Jun 06 2010, 02:20AM
Location: Dresden, Germany
Posts: 727

You suffer from Creationism. Go get a doctor!

Sry to give you a hint of reality, but ideas and theory are generally worthless until you actually build something. Even the discussion of the idea itself is questionable as long as its not about actual specific problems. You know how many awesome computer games we would have if having an idea and problem solving by knowing "others showed it can be implemented like this.." would actually suffice?

Its not actually that hard, just requires some creative thinking to build it.
The tricky part now would be building a test coil before spending probably 2 weeks making the full scale version

So you contacted Ebay resellers about something you arent even willing to put 2 weeks additional development time in. I sure know what my answer to such request would be....

is something like this actually feasible?

You already contacted resellers right? So either you talked to them about a total brainfart or you already determined its feasible.

A chip-scale atomic clock

Just WHY?

But back to the original question: is it feasible?
It does not matter. If you need help to get even the raw concept work done you are far away from reaching any productive state.

1487497345 2906 FT178984 Development Cycle

Please think honestly about where you are on the graph and where the most ideas end up. Unless you havent survived the trough, feasibility follows the probability of having a really good idea. Close to 0.

I know this post wont gain my any polularity, but i had to let it out.

Enceladus

Sun Feb 19 2017, 01:29PM

Registered Member #61428 Joined: Sat Jan 14 2017, 12:39PM
Location:
Posts: 50

DerAlbi wrote ...

You suffer from Creationism. Go get a doctor!

Its not actually that hard, just requires some creative thinking to build it.
The tricky part now would be building a test coil before spending probably 2 weeks making the full scale version

So you contacted Ebay resellers about something you arent even willing to put 2 weeks additional development time in. I sure know what my answer to such request would be....

is something like this actually feasible?

You already contacted resellers right? So either you talked to them about a total brainfart or you already determined its feasible.

A chip-scale atomic clock

Just WHY?

But back to the original question: is it feasible?
It does not matter. If you need help to get even the raw concept work done you are far away from reaching any productive state.

Harsh... but it's the gods truth.

Conundrum

Sun Feb 19 2017, 08:14PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

Its based on a new coil design, where instead of trying to wind a linear (conventional) TC or making a bulky hard-to-wind flat secondary I plan to stack lots of small optically translucent PCBs vertically with interconnects between them formed with low temperature alloy dots alternating with drilled spacers and the correct geometry on both sides so the output voltage is comparable to a secondary many times this length.
The use of UV setting glue (actually nail varnish) adds some level of protection to the stack, and I've already determined that this approach works as it is used already in optical drives. Ever taken a <2005 block apart, this is how they make all that technology fit.
The PCBs can be tested as I assemble the coil(s) and if one does go bad (see earlier) it can be carefully removed and replaced.

Yes, using 13.56 MHz is to stay within the ISM band, reduce interference and allow the use of relatively compact transformers even possibly PZTs as some of the newer units operate this high to get the increased power handling capability.

I once tried this with copper stock and amazingly it was translucent enough to expose the PCB photoresist underneath slightly with FR-4 (Bungard) boards.
The lamp here is around 375nm UVA and is far too powerful but fine for experimentation, modified two magnetometers with graphite shielding and fragments of clear plastic so the contacts on the PCB don't short out.
A short burst of heat while UV exposure is on helps a bit here so this is a handy tip for replication

Sulaiman

Sun Feb 19 2017, 08:29PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

Collectors and displayers of elements to make display Periodic Table Of The Elements
need a hv rf source to show off the emission lines of gasses.
Not a huge market, but it could be a loyal one.
I bet you could sell a few dozen easily.

What you need is a killer application, gas leak detection or something like that ?

An eBay product may involve continuous litigation . too many assholes
(probably literally, depending upon product dimensions and topology :)

Conundrum

Sun Feb 19 2017, 08:35PM

Registered Member #96 Joined: Thu Feb 09 2006, 05:37PM
Location: CI, Earth
Posts: 4062

Interesting, thanks for this.
I was planning to use it for something similar, being able to test fluorescent tubes at a distance would also be handy.
One of the big complaints of folks using mains powered TCs for science demonstrations is that they have endless issues with H&S because of the mains in case a potentially lethal conductive streamer forms between a concealed live mains connection and the operator.

As an aside, one slightly crazy idea is as an "if all else fails" fix for screen burn on OLEDs, as otherwise the panels would get trashed.
A lot of the time just IR exposure helps a little but you really need to use high field strength at low enough frequency while the panel is in dark mode in order to get the indium to electromigrate back out of the emissive area(s) and reconfigure the DPA back into its pi-bonded emissive form.

I have a couple of phones here with this problem which are basically worthless until the screen is changed because the menu bar is permanently visible even on a webpage and sucky brightness (<60% of new)

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