Instructables
Are you tired of those old black speakers that only just make sounds? Maybe sound reactive lights are just not enough to impress you? How about a Plasma Speaker?

A plasma speaker is a device that generates an high voltage electrical arc that makes purple light and music! Without any speakers or any moving parts! Sounds too good to be true? Well, you're wrong, the high voltage arc really does 'sing' by vibrating in the air. (Of course, you will need to give the device musical audio for it to work.) And just leave this instructable if you still don't believe me...

And this is something I always wanted to build - I have been dreaming to build one for about 6 months, until Kiteman has greatly boosted my encouragement to build one. (Thanks Kiteman!)

The video of my plasma speaker - early prototype.

Step 1: The dangers you must know...

Picture of The dangers you must know...
A plasma speaker is no toy...

Health Hazard
Unlike the ordinary speakers, the plasma speaker are dangerous high voltage device, do NOT attempt to build this device unless you know what you are doing... And do NOT even attempt to build one if you have heart problems or weak heart or wearing a pacemaker, because one little shock from this thing can put you out...
I am not responsible for any injuries or deaths caused by this device.

Why should you know all of this? it is because you can ONLY live once, and no more...
If you don't think that you shouldn't build one, just watch movies of it working instead, much better than risking your life to build and operate one.
If you think you are okay to build one without killing your self, then move on to the next step.

Hazard to Electronics
Since the plasma speaker generates high voltages, there is a chance there will be high voltage spikes on the low voltage side of the device, which can get onto the audio line and damage (or destroy) the player. They are some safety features to prevent the spikes damaging the player, but they can fail... So I am not responsible if your player gets damaged, and use cheap players like CD players, if you're rich, you can use expensive players if you want. :-)

Step 2: Schematics

I got the idea from scopeboy's website on his flyback driver section, but the schematic was quite complex and buying four MOSFET's is a little too expensive for me...

So I simplified the design to using one MOSFET.

I get a lot of complainants of this project is not working very well or at all. This new design WORKs, however, for most people it may not work. This is due to the MOSFET (and some other components) is poor quality.

I just recently found out that manufacture who makes the components sell the best quality ones to other manufactures and sell the poorer quality ones to the whole sellers and retailers. For this project, the best grade MOSFET's is critical, and it can only be gotten by salvaging old electronic devices, unless you are willing to pay for thousands of components for the manufacture... :-)

Step 3: So, how does it actually work!?!?!?

Picture of So, how does it actually work!?!?!?
Okay, you must be very curious how the plasma speaker works...

Note: This information is technical, skip this step if you don't understand...

The TL494 acts like an oscillator and a modulator, it generates a high frequency (5KHz to 45KHz) to drive the flyback transformer to make high voltage arcs. Then when you give it audio, the TL494 modulates the audio frequency into the main high frequency. Now the flyback transformer is being driven by the high frequency and the audio frequency, and when the arc is produced, the arc vibrates the air with both the audio and high frequency creating sounds.
If you tune up the 22K potentiometer, the high frequency increases, when it goes higher than 20KHz, we cannot hear it, but only the audio frequency...

I hope you can kinda understand this..

Step 4: What you will need...

Picture of What you will need...
P3090014.JPG
You will need quite a lot of stuff to make the plasma speaker...

Parts:
  • TL494 chip (Datasheet for TL494)
  • 200uF (or 220uF) - 50v electrolytic capacitor
  • 47nF - 250v (or similar voltage ratings) capacitor
  • 100nF - 50v capacitor
  • 10nF - 50v capacitor
  • 2.2K - 1/4W resistor
  • 10 ohm - 1/4W resistor
  • UF4007 diode (or other fast diode that is rated 1A (or more) and 500v (or more)
  • 10K - 1/4W potentiometer (same thing as a variable resistor)
  • 22K - 1/4W potentiometer (same thing as a variable resistor)
  • Audio jack
  • Wires
  • IRF540 MOSFET (other MOSFET's with similar ratings should work)
  • Large heatsink
  • Flyback transformer (can be found from old CRT.)
  • 12v power source (for TL494 oscillator / I used a 9v battery)
  • 12v to 40v power source (for the flyback transformer)
  • Breadboard (for testing)
  • Veroboard

I bought most of my electronic parts from Farnell.

Tools:
  • Soldering iron
  • Wire strippers
  • Wire cutters
  • Pliers
  • Helping hands
  • Hot glue gun

Abilities:
  • Good with a soldering iron.
  • Can read schematics.
  • Know what you are doing when you are dealing with high voltage.

Step 5: Build the prototype on the bread board

Do what the title says... Build the circuit on the bread board!

Why on a bread board and not build it directly onto the veroboard?

Well, it is a very good idea to build the prototype on the bread board before you solder the components onto the veroboard because...
  • You will get a better idea on how to build a 'real' one on the veroboard.
  • You can make sure all the components are working fine, if not, you can replace it easily.
  • You can modify or tweet the circuit a bit to give the plasma speaker a better performance.

I built my circuit using my simplified schematic on the bread board that is connected to the "Electronic Lab" kit that I got a long time ago.

To connect the flyback transformer to the circuit, wind 5 or more turns of thick solid-core wire on the ferrite core. That will be your primary coil.

Step 6: Test the prototype

After you had built it, go ahead and test it!
If it does not work, don't get all frustrated or anything like that, go back and check your circuit closely, make sure there are no missing connections, and check the components are properly connected to the circuit...

Mine works quite well, unfortunately, the MOSFET is wasting large amounts of energy into heat, so it is blazing hot... I have to make the heat sink bigger to try keep it cool longer. But it still goes blazing hot after three minutes of continuous operation.
Oh well, that is my efficient design so far...

If yours working well with out very much problem, thats great!

Step 7: Build the circuit

After you have tested to make sure everything is working, start building the prototype onto the veroboard.

If you notice in the pictures, I use an 16 pin socket for the TL494, it is really good idea to use sockets for the IC' s because you won't risk heat damage from soldering, and if the IC fails, you can easily replace it instead of desoldering it and solder another one in..
I also added an LED indicator, that is a good idea to add that on too, so you know whether the circuit is on or off. The LED indicator is connected to the TL494's power supply line.

After you had done soldering, make sure you made nice shiny solder joints and they are no solder bridges. If you think it is all good enough, add some dab of hot glue onto the loose components and wires for strain relief.

Step 8: Final test

Picture of Final test
Okay, you are very close...
Test your plasma speaker to make sure if it is working or not.

If its working, let out a sigh of relive that you did it!

If its not working, don't overreact of frustrated, (I know it is very frustrating when something does not work).
A few things can go wrong with this circuit, here is a list of some problems...
  • Solder bridge - That is the most common problem in soldering.
  • Some connections missed out - Also another common problem...
  • Damaged components
Try find and fix the problem, there is no point giving up - unless you are really lazy to do so...

After you got your plasma speaker working, it is a good idea to the circuit into a project box. I will protect the electronics from being damaged from foreign objects and protects people from an electrical shock.

Step 9: Enjoy and impress your friends!

Well, there is the instructions to make your own Plasma Speaker! Go ahead and pump in your favorite music then listen and watch the arc dance with the music and admire what you had built...

Then show it to your friends and family, I can guarantee you they will be greatly impressed.

When my Dad first saw my plasma speaker in operation, his first words about it are: "What the f... Tha... Thats impossible." He is wrong, nothing is impossible... Nothing.

Step 10: How to use the plasma speaker

Picture of How to use the plasma speaker
Here is how you can control the plasma speaker with the two potentiometers.

The 10K potentiometer is used to change the TL494's internal oscillator frequency - from 5KHz to 50KHz. If you want to play music on the arc, tune the frequency up until you don't hear it and play the music. Note: The 10K potentiometer does NOT affect the input audio (music).

I am not too sure what the 22K potentiometer's job is, but it seems to change the volume of the audio, fiddle with the 22K potentiometer until you can hear the music loudly. Note: Making the music louder will shorten the length of the arc.

Step 11: Interesting discharges...

Just a little story I like to tell you about...

While I was testing (well, playing) my plasma speaker, the 12v battery is going flat and the arcs are becoming unimpressively short. So I replaced the battery with my lab PSU I modified from an ATX PSU and put an 22,000uF capacitor in parallel with its 12v output and ground.
The 22,000uF capacitor is used to adsorb any high voltage spikes that may appear on the line.

When I connect the PSU's power to the plasma speaker and turned it on...

The arc are very different, instead of a sting of purple light, the arc flaps furiously and it makes very interesting light display. But this is not suitable for a plasma speaker, because the arcs flaps so much it just simply drowned out the music...

Here is a video of the arcs.



Well, I hoped you enjoyed this instructable!
If you have any questions, or need help, or found an error, or anything, make a comment! I like comments! :-)
 
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_Totoro_1 month ago

In the schematic it says 47nF 2kV which you corrected to be 47uF 250V, but in the parts list it says 47nF 250V, so is it 47uF or 47nF? Thanks

MrElectron7 months ago

I like the design and may attempt something similar sometime, however I did notice one thing in the schematic that would perhaps explain why the mosfet was getting so hot. there is no gate to ground resistor, meaning that the gate goes from 12v to 12v and high impedence when it should be going from high to low. the tl494 has an essentially open emitter output to the mosfet, otherwise I like the idea of using dead time control as modulation, very cool.

What's your solution to the heat problem? Just putting a resistor from gate to ground?

Also, read the datasheet for the tl494, it will show that the gate driving pin is an "open source connected transistor" (google it if you want to) and my previous comments will make sense.

There is probable a pull down resistor in the tl494 or the mosfet gate, thus the circuit works in the first place, however the mosfet is probably switching slowly or partially, due to the high driving impedance on a low impedance gate. If the gate to ground resistor doesn't work, try heat sinking the mosfet along with it. I reccommend a resistor value of around 100-1000 ohms, try 1000 first.

Dillon123 4 months ago

the 22k potentiometer controls the duty cycle or the power supplied to the flyback

j0ch3m19881 year ago
Dear Plasmana,

I used my plasmaspeaker for over a year now but I have a problem.
I always used a laptop power supply (90 watt) for the flyback transformer and last week I bought a heavyduty power supply (50 volt/16 amps, 800VA) and now I killed my MOSFET (IRF640). My question is; wich MOSFET can I use for pulling a few hundred watts without killing it. The max the IRF640 took was 26 volts and about 3.80 amps (at 30 volt and 4 amps it blew up). I had a 2SK1082 MOSFET laying arround but that doesnt work very well. I got a very little arc from that one.

Please help me, I really need a MOSFET that can handle much more current/voltage and still give a nice big fat arc from the flyback.

Greetings,
Jochem

irf3205 it has 110 amps of current handling and 55 volts

there made for car batteries

It's not really about the MOSFET handling current but rather the switching. Get some IRF540's on Ebay for about a dollar a piece and they're 100V, 30A.
Thnx for the reply,
I got 2 irfb20n50k's now. 500V 20A and I guess they can handle 280 watt at 25 degrees celcius. Atleast that is what I read in the datasheet. :) This MOSFET works great at 35V and 3.4A but I don't want to blow it up, haha. Got a 50V 16A (800VA) toroidal transformer attached to it with a variac and a 100V 22000uF capacitor.
This MOSFET don't get that hot with a CPU cooler attached to it and I got a pretty long and loud arc. But I guess the MOSFET can handle even more! :)
Here is a movie of my power supply and plasma speaker (only on 25V) :p
Sweet setup and spark! =)
When ever I bother myself to make another of these I think I'm gonna add a 148watt Peltier cooler. Might help those poor MOSFETS from dying? =)
good idea about using a cooler but one side of them gets really hot so your just moving the problem. im probably wrong. will the cool side being heated by the MOSFET cancel out the other side from overheating.
Hey Crimson-Deity,
Here is just another video of my plasma speaker at 34 volt this time.
The arc is now longer and louder! :)
I will probably crank the voltage up some more in the near future, but I really hope I don't pop the MOSFET. :P
Thnx, I still need to build the variac, bridge rectifier and capacitor in a box :)
And maybe I will build a volt and amp meter in it aswell. Looks alot better then a separate volt and amp meter if u ask me! :)
I bought this stuff a week ago so that's why it lays all over the floor. :p

About dying of MOSFETS, I guess if u stay in the voltage, amps and watt range of what they can handle, u will be fine and keep them cool as possible. :)
cheshirecorn6 months ago

Thats helpful

Absolutely!

RocketPenguin9 months ago
Alright. So i built this with blind luck (Many of the projects i try to replicate fail in some way shape or form...) And well, i was surprised it actually worked! The shock was electrifying!! (No pun intended) But alas, i do have an issue.
When i powered it on, it worked at an extremely high frequency, but even worse, it blew out my power supply! Now, this was an older power supply i scavanged from a satellite dish box or something (It had +5 +12 +22 and +30 which was much better than my ATX, considering it only goes up to +12 volts...) This being the first time trying it out, i thought maybe it was a bad power supply that was already bad, i just finished it off. I was wrong. I pulled out my 12 volt SLA battery, to use that instead. Not sure if it was the power supply's fault last time, i decided to only turn it on for a few seconds. The cable leading to the board got really hot, the battery got warm (Uh oh...) and the mosftet got hot to the touch; Only in a matter of seconds! Thankfully, the battery is still ok at the time of writing, but what would be the cause of such an issue? I am thinking it may be shorting somewhere, but looking with my multimeter i dont seem to find any errors. Only the mosfet and the power cables get extremely warm as far as i know. Any ideas? Great 'able BTW, was very easy to follow and understand.
UPDATE: Alright, so i swapped out all the wires with 14 gauge wire, which by the way is complete overkill, and tried using an ATX power supply. The ATX didn't even try powering it, being way too high of a current for it to do anything...
Any idea why this is happening?!
ivver10 months ago
Is it possible to somehow use plasma globe (ball) as plasma speaker (ofc, when you take out the globe)? I have problem with flyback trasformer, I can't get it working somehow.. But, I have broken plasma ball so I have driver for ball which I don't need..
Thanx in advice.
123456dang1 year ago
And the flyback transformer I can see it has a lot of leg so which one can I solder the coils in? And one more that can I replace the coils with the spark plug in the car?
123456dang1 year ago
I read it and I wondering that what can I do to protect my phone which will have a chance be strike from tesla coils? help me please!
Thats incredibly good
For those of you interested in building a plasma speaker, there's a nice plasma speaker kit offered by excelphysics that includes everything you need to build one! http://excelphysics.com/collections/frontpage/products/arc-plasma-speaker-kit
I replace the MOSFEt with a IRFP4004PBF 40V 350A. Now it doesn't even get warm and the spark i fat. Just a heads-up.
ivver1 year ago
Could you put this circuit to the Tesla coil? I mean, will it be the same results when you put flyback and Tesla coil?
Itchago1 year ago
Why do you have a separate power supply for the flyback? Isnt the power comming from the circuit? What i can see from the schematic it would be going to the Mosfet? Also, is it possible to use a Ignition coil instead of a Flyback?
Wait so do you need to use a battery? Will a power supply like this work for both the flyback and circuit simultaneously? If it's not steady enough I have a 12v VRM and some caps. About how much current does this use?
France941 year ago
Hi, i didn't get how to wire the ground, have i to connect the two negatives of both battery and power supply together or is it somehow different?
please help me, 'cause i've built all the rest right and it doesn't work.
PS is there any difference in using a "non solid core copper wire" for the windings?
jwoo20231 year ago
The Plasma in the video looks like its dancing and singing to the song! :P
hey what about if a 5 watt amp is placed before the flyback
hey what about if a 5 watt amp is placed before the flyback
wrecklesst1 year ago
THe way this works is exactly like how we get fm radio or any radio. The actual audio signal is too weak for you to pick up fromany distance in comparison the audio here is too weak to power the plasma generation. So we need a carrier and that is the high frequency. High enough to power the plasma generation and as stated above when you set it too a vibration above what the human ear can pick up it is in essence silent (your dog will disagree) same with radio a carrier signal with enough power to transmit over a great distance is used and the actuall audio signal you pick up with your radio is mixed into this carrier and your reciever picks it out..

AMAZING STUFF I freakin love that you did this. I made a little prototype much like your original one. I was going to make a final one and was excited then I put the project down and it has been forgotten. That was almost ten years ago. I am once again excited about thi and am starting my build again. Thanks,

Nice job
Ohh and to anyone else reading the warning given for this build is no joke and it isnt just a warning like be careful itll shock you It is very seriously do not do unless you are 100 percent sure you kow about the fundamentals of electricity. You must understand how electricity works and how to protect your self from its power. This can kill. If you have even a little doubt then you are not ready to do this. Go and read up on electricity there are uhndreds of tutorials on it. \
With that said anyone with the experience and knowledge will love the display this gives. I was amazed the first time it was to unbelievable
iceng2 years ago
Your video won't play....
Says " This video is private. "..
Can you let me see it ?

A
bobzjr2 years ago
This looks cool and very dangerous.
Love The Smiths!
you said you meant 47uf instead od 47nf witch one is right ?
(removed by author or community request)
i meant : instead of
will it kill you and if it won't how bad is the shock?
htc1094 years ago
 can anyone give me advice on a good enough power source or atleast how to make one using some kind of batteries or power adapters????
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