# Plasmaduino ...maybe this year!



## corey872 (Jan 10, 2010)




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## David_AVD (Nov 9, 2012)

So .... it's a plasma ball ?


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## corey872 (Jan 10, 2010)

Yessir, it is! But not just a plasma globe... a plasma globe driven by an arduino! Hoping to post more details soon. (Though that may be a relative term as I have been prototyping the HV drive section for the past ~15 years- lol!)


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## RoxyBlue (Oct 6, 2008)

Wicked cool!


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## corey872 (Jan 10, 2010)

Thanks, all. I was hoping to upload some more video / info on this project -but it continues the trend! I typically pull it off the basement shelf thinking I'll get the globe running for Halloween... doesn't really fit in the 'graveyard' theme, but with the cool green and pink color combo, why not! So I spend a few months burning up various electronic components until all my mosfets, transistors, control chips or what ever are dead and it's too late to get another order in before Halloween.

So this year's question... can a sketch brick an arduino?

Sure I realize you could set all pins to output and short them, or possibly put the TX.RX pins in some tight endless loop. But here is the issue now:

I was setting this thing up with an LM3524 PWM chip to handle frequency, duty cycle, current limiting, etc. Had that pretty much running last year, but burned out my last few mosfets before finding the source of the error... had set the circuit board down on a small flake of used solder and shorted a few critical pins.

This year, I got everything running smoothly and thought 'wouldn't it be neat to throw an arduino on top of the 3524 to do some control for 'special effects' Thought possibly the arduino wouldn't last in the EMF environment... but running for dozens of hours over the past month and uploading 10s if not 100s of sketches, it seemed to do fine.

Then one night, I uploaded the latest version of my sketch and couldn't seem to get any output. Did a bunch of troublshooting and finally tried reverting to the previous (known working) sketch and could not get it to upload. 

Messed around for a few more days trying to troubleshoot, finally pulled a brand new nano out of the package and tried the upload... it seemed to work. So thought I'd try the exact sames steps again and the brand new arduino started giving the same errors.

So either two arduinos have suddenly 'gone bad' or a sketch which was known to be working is suddenly 'bricking' them. Hummmm.... now awaiting a shipment of new arduinos! Fingers crossed they will be here soon!


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## corey872 (Jan 10, 2010)

Looks like we're quickly counting down through the double digits 'till Halloween '19, and as this project continued its 'suddenly dying just in time for the big day' trend last year, I thought I'd post an update for this year:

TLDR version; With a few weeks to spare last year, I wanted to move the 'guts' of this over to my latest revision circuit boards which had just been delivered. Of course, they had one tiny production defect - on the one exact terminal required for the driving signal, so the whole operation became erratic. Weeks of troubleshooting meant no plasma globe for Halloween 2018 - and back on the shelf for another year!

Getting started (a bit) earlier this year! Some photos below.

Long Version:

So as time wound down in '18 I thought, "Hey just enough time to order one more revision of the circuit board, get everything assembled, and working great." &#8230; plus order another stack of Arduinos to fix the programming issues noted in the post from last year, above.

So middle October '18, the arduino's show up at about the same time as the revised driver circuit boards and I begin working to quickly assemble everything, and get the globe working on the new hardware.

Well, guess what!! As usual, everything goes to crap in the transfer. I finally track the Arduino programming issue to an obscure setting in the processor section not calling for the "old bootloader" Prior to this, I had no idea what it was - so did this setting just change on its own??

Anyway, putting the check box back to "old bootloader" I was able to upload sketches again, then it was time to get on that driver circuit. So I quickly soldered up a new circuit board with brand new components and to my disappointment, it works randomly at best!

Spent the next several weeks swapping components back and forth, trying to see if it was the circuit board, power supply, controls, programming, or whatever. No Luck! So the Halloween '18 came and went with the plasma globe on the shelf collecting dust as always. 
Finally around March/April I back to troubleshooting. Seemed like the issue was definitely in the circuit board, but why do the old boards work fine while the new ones (same circuit, just better layout) work so randomly.

Well, here is why!!



Somehow, some of the holes on the circuit board escaped the through-plating process. Of course, this one exact hole is the 'drive output' for the whole circuit and of course, the signal needs to enter on the board top, transfer down the plating and out the bottom. No plating, no signal!

So working on a bit earlier start this year! More circuit boards, bit of revised programming and we will see!


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## RoxyBlue (Oct 6, 2008)

Trouble shooting electronics can be so frustrating. Takes the patience of Job to get though it:jol: Fingers crossed it all works out for you this time.


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## corey872 (Jan 10, 2010)

RoxyBlue said:


> Trouble shooting electronics can be so frustrating. Takes the patience of Job to get though it:jol: Fingers crossed it all works out for you this time.


Boy, that is not the half of it! Troubleshooting electronics is frustrating, me troubleshooting my novice electronics is even more so, throw in my novice arduino skills to add double or triple the misery, then multiply that by a factor of 10 when high voltage is involved and things tend to go 'poof' without any real warning or trace of what really happened and/or one mistake takes out a whole hand full of components.

But hopefully the worst is behind now! Revision 38... or is it 41? 56? Well, somewhere deep in the double digits ...is coming along nicely.

I've gone back and forth over the years... having a separate HV driver board or not. Back in the early designs, this thing needed 100+ watts and massive cooling, so separate boards were almost a requirement.

Through a lot of tuning, tweaking and finding better designs, the 'plasmaduino' video above was shot running a bit under 20 watts. That was just a single mosfet driving a square wave to the high voltage flyback transformer.

Since revising that, I've decided to try a half-bridge design which I hope will give even more output, effectively allowing a reduction on input power again. At that point, it starts to be pretty feasible to run this off a set of lithium rechargeable batteries.

So we will see! Making some progress, but still waiting on some components:


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## Batbuddy (Sep 3, 2014)

Again you amaze me! looks great. and great job on the woodwork too. I want to know where you got that awesome custom face panel? did you make that too?


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## corey872 (Jan 10, 2010)

Thanks. This has gone a bit beyond the old "hot glue, zip ties and plywood" props I normally do, but I figure I will have this thing our year around once it's finally done, so it's evolved to a bit more 'piece of furniture / art work' as opposed to just Halloween.

Yes - the instrument panel is full custom to fit my switches, modes, indicators and the effects I've put in the arduino, courtesy of PaintShop. I just drew up something suitably 'old-timey' and printed it out. I may stick with it, or there are also several places offering 'metal print' options, so could have the image directly printed to a piece of metal. Figured that would be a great 'finishing touch' if I ever get that far!


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## corey872 (Jan 10, 2010)

Thought I'd do a quick update. I had some time over the long weekend to get everything assembled and do some trial runs. Everything seems to work... so hopefully, I can get everything put back together and give the programming side a good scrubbing to remove all the kludge I've added over the year(s). Of course, THAT will probably break something, too - but at least I can just go back a version or two and recover!


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## Batbuddy (Sep 3, 2014)

Super cool. Where did you get the plasma sphere anyway?


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## corey872 (Jan 10, 2010)

I happened to find them at American Science & Surplus. This was ~17 or 18 years ago now, though! Their supply is long gone. But they have some other interesting odd ball stuff if you want to have a look.

https://www.sciplus.com/

I bought five of these as 'mis-fills' or 'most likely not working'. When they showed up, four did have a broken stem meaning the gas had escaped and air got into the globe...but that should be fixable with a little glass work. This globe was still sealed and to my surprise, when I first hit it with high voltage, gave a very eerie green / pink glow... not the standard blue/pink of the 'typical' neon/argon globes.


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## corey872 (Jan 10, 2010)

Well, fully realizing I sound like a broken record - after the weekend of testing - I sent off for one final revision of the circuit. ...and I really mean FINAL!! It's even in the name of the file "Final Plasmaduino.brd"

It's going to be an arduino uno shield. The separate boards above are great for prototyping and troubleshooting, but quickly become a rats nest of wires to package into any working equipment.

Also over the weekend, I ran a frequency sweep - mainly to remind myself / confirm the best frequency for this globe. I think the display looks the absolute best at ~7.5KHz - but of course, that is right in the 'sonic' range, so the transformer and drive circuit emit a very audible high pitched squeal. The next best frequency seems to be 14.7KHz - a bit more 'lively' in the way the streamers dance and about 95% of the visual 'goodness'. Plus I can't hear anything so that is what I will run.

My earlier boards had adjustable frequency, but there are generally only 2-3 'peak' frequencies where the globe looks really good and you can quickly get 'out in the weeds' on some frequency where the globe is dim, but actually drawing a lot of current - so I figured the ideal operation would be to just lock into the 'best' frequency and make effects based on timing and other things.

On a side note, I also ran one of the standard "Radio Shack" blue/pink globes - it loves to run at 44.5KHz - so possibly a plasmaduino conversion in its future as well.

I also took some time to play with the number of primary windings on the flyback transformer. Tried everything from 2 to 22. Turns out, 13 was the magic number with a notable decrease in performance even going to 12 or 14.

I also ran all my tests at 20 volts - as that seems to be a pretty common lithium battery voltage for power tools. So I can now make a pretty lively display with 1 amp current draw - or less. Given 3, 4 or even 5 amp-hour batteries are pretty common, I should be able to keep the globe going (silently!) for many hours or even an entire evening.

Hope to get some more videos up soon!


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## Batbuddy (Sep 3, 2014)

Looking forward to the video! If you are willing, I would love to see a video of the insides...


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## corey872 (Jan 10, 2010)

OK well, here is the final form - an arduino uno shield. Not sure why I didn't just do this from the beginning as it eliminates about half the wires transferring power and signal between two boards. Just power input (red and black, on the left) and flyback transformer primary drive output (oranges on the right) ...and a small nest of wires on the input header (front) for things like speed, intensity, effect, volt/amp mode... and, of course, the ghost sensor!

Looking forward to getting the guts stuffed back in this monster and having some play time!


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## Batbuddy (Sep 3, 2014)

Cool! Nice work. Much cleaner I am sure. I like the 3d printed base for the Uno as well. Are you using Eagle for your shield design? And who is the board manufacturer?


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## corey872 (Jan 10, 2010)

Yes - I guess to thank some of my "sponsors" - lol...

EAGLE 6.5 for the board design/layout
(7.0+ is terrible IMHO because they took all the color/dimension out of the UI making it a real pain to work with)

OSHPark for the board manufacturing
(3 copies of any design for ~$5 per square inch, about 2-3 week turnaround. Might be some cheaper, and/or faster places?)

BobCAD 23 for the 3D case design
(BobCAD is crappy in general and 24+ is terrible IMHO because they also redesigned the UI roughly doubling the amount of 'clicks' needed to make anything happen and taking out many of the color queues... but it's the 3D software I know.)

Cura 4.2 for the 3D slicer
(Jury is out here... somehow they make it take 3-4x as long as Cura 3.6 to open, and it doesn't actually seem to do anything more)

Creality CR10S 3D printer
(For the price, seems to be decent quality and large volume)

Arduino IDE 1.8.9
(Yay one piece of software that just works!)

American Science and Surplus for the plasma globe
(Though the globes are long gone / no stock, now)

Digikey for many of the electronic parts
(one of the best parametric searches IMHO)

ebay for a bunch of other electronic parts
(Cheaper than digikey, especially considering digikey tacks $7+ shipping on every order. But typically a 2-3 week delivery time as the parts come on the slow boat from China.)


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## Batbuddy (Sep 3, 2014)

Cool. Thanks for this little review of what you are using. Thought I would share a couple of sources that I like for some of the things you mentioned that were lack luster. I have used https://www.taydaelectronics.com/ for electronics and they are much more reasonable with pricing and delivery speed. I like mouser better than digikey but they are both pricey. I use SketchUp for my 3D print design and I love it. It is pretty easy to use and quite powerful also a lot of tutorials available, but it is a learning curve like with any new software.
Love you project though and I am really impressed with the quality of the craftsmanship you are putting into it.


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## Daphne (Oct 18, 2006)

I can honestly say I didn't understand pretty much any of that but holy cow it looks SO cool! Plasma balls are really cool to start with. Love your take on this!


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