In this tutorial, I want to write down and share an awesome project we made in our school, a tesla coil, which can make music. I will explain every step in detail, so people who are not experienced with tesla coils or programming. I will divide this instructable into two parts, in the first we will build a normal tesla coil, in the second one I will explain the programming in detail, and how the microcontroller gets included in the circuit.

First of all: Be careful! You are working with high voltage which can be deadly if you get careless or frivolous.

I added a plan of the circuit below to make everything clear for you ;)

## Step 1: Step 1: the Frame

First of all you have to build the frame, which contains the two main coils fo the tesla: the primary and the secondary coil. We chose to build a frame with two floors. In the bottom floor there is the spark gap and on the second one the primary coil. The secondary coil is placed on the bottom floor to get some stability through the hole in the first floor. Drill the small hole for the primary after putting it through the pillars because then you exactly know where you have to drill it.

The frame is made out of normal wood which we found in our homes. We also buyed a few pieces of wood in the building center. You just have to ask for rest-wood of other people so you can get it really cheap. The single parts can be connected with glue or screws but try to minimize the metal parts on the surface of the upper floor.

The spark gap actually is nothing more than two larger screws with space between them, which can be regulated, because you have to find out how the configuration will be. The space should be variable. The final space depends on the voltage, which you have in the circuit of the primary coil, you can say: you need 3.000 V for distance of one mm.

We created a model of our frame in blender, so you can have a look on it by yourself. In the ZIP-archive below, you can get the model of the frame to plan your own. Feel free to change it in any way if you have to.

## Step 2: Step 2: the Secondary Coil

The secondary coil is very easy to build. The base are some insulated wire (ours is about 0.2mm thick) and a PVC pipe. Be careful while winding the wire on the pipe and take care that there are no crossed-over wires or spaces between the windings.

On the upper end of the coil the toroid will be placed. In our case it is a styrofoam donut. To make it conductive you cover it with aluminum foil. Before connecting the wire of the secondary coil to the toroid, polish the end of the wire with some sand paper to remove the insulator from the wire. If you skip this tiny but important part the connection won’t work. The bottom end of the secondary coil leads to the earth.

Before connecting the toroid to the coil you should check if there is a connectin between the two parts. You can do this with a battery and a tiny lamp or LED.

## Step 3: Step 3: the Primary Coil

You can buy these copper wires on the internet for about 30€ and they have a very good quality. To get it in the right shape is tricky but you can handle it with some patience. The bottom end of the primary goes to the spark gap, the upper one to the capacitors which we build in the next step.

Drill some holes in the pillars on the second floor to get the copper coil through it. This will provide some stability in the three upper windings and makes it easiar to balance the remaining windings.

Put the "beginning" of the primary through a small hole next to the larger one in the wood to get access in the first floor. This will improove stabilty too.

## Step 4: Step 4: the Capacitors

A very simple capacitor can be made with an empty case of beer. The bottles are filled with salt water. The concentration is not that important, but ours worked very well with 100g/l. On top of the water there is some oil to the upper end of the bottle which gets sealed with a cork. After this step there shouldn't be air between the cork and the oil.

Before putting the cork in the bottle, put a wire through it, which is long enough to touch the salt water. The salt water is the first plate of the capacitor, the glass of the bottle is the insulator. Put aluminum foil around the bottom side of the bottle, which is the second plate. Make sure that the aluminum foil is tight on the surface of the bottle.

Just because it looks good, we turned 20 bottles into capacitors. The idea behind our composition is, that you can add or remove single bottles without a large effort, to regulate the capacity of the capacitors, which is important because you can't say how many capacitors you will need in the end.

## Step 5: Step 5: Connect Everything

Now you have all parts together, all you need to do is to connect them in the right way. The upper end of the capacitors gets connected with the primary, the lower end goes to one side of the spark gap. The other end of the spark gap is connected with the bottom end of the primary coil.

The power supply, which should have around 3-5 kV (use a transformer) is connected parallel to the spark gap.

## Step 6: Step 6: Try It Out

It is a kind of game to find the right adjustments for the tesla coil (number of bottles, space in the spark gap, ...), but if you have found the right one, you will see nice sparks. Make sure that the power supply is turned OFF, when you touch any parts and make sure that you are in a safe distance while running the coil!)

In the second part of this instructable I'll show you how to programm the microcontroller and how you build a nice GUI for your tesla to make it sing.

Leave comments or criticism in the comments, because it's my first instructable so I want to know how to make better ones ;)
<p>where are part 2&amp;3?</p>
Are the bottles the only way to make a capacitor or are there other ways
<p>As I wrote in my instructable, the bottles are the cheapest way. This method is called &quot;Leyden jar&quot;.</p><p>The other method would be the plate capacitor, which is based on the same principle. You combine two plates with one isolated layer between them but in contrast to the bottle capacitor, you can combine more layers. On this page there is a nice tutorial how to do this: </p><p><a href="http://www.drachenschuppe.de/experiments/highvoltage/homemadecap.htm" rel="nofollow">http://www.drachenschuppe.de/experiments/highvolta...</a></p><p>It is in German but the picture in the center should show you what I mean.</p>
<p>Do you have any video?</p>
<p>I will add a video of the running coil as soon as I can. The transformer in our school is damaged so we have to wait until the new one is there. ;)</p>
You said you used a transformer for power supply and wired it in parallel. Would that be a delta connection or a wye connection?
<p>I added a plan of the circuit, I hope you find it helpful!</p>