Homemade Levitron. How to create a levitation effect with arduino. We connect everything to the heap

The idea of the device is very simple, an electromagnet lifts a magnet into the air, and to create the effect of levitation in a magnetic field, it is connected to a high-frequency source, which either raises or lowers the object.

Step 1: device diagram

The circuit is surprisingly simple and I believe that it will not be difficult for you to assemble a Levitron with your own hands. Here is a list of the components:

LED (any color is optional)
Irfz44n transistor (or any suitable mosfet)
diode HER207 (1n4007 should work just as well)
1k and 330Om resistors (the latter is optional)
Hall sensor A3144 (or similar)
copper winding wire with a diameter of 0.3 - 0.4 mm and a length of 20 m
neodymium magnets (I used 5 * 1mm)

Step 2: assembly

Let's start assembling. First, we need to make a frame for an electromagnet of approximately the following dimensions: a diameter of 6 mm, a skein height of about 23 mm, and a diameter of the lugs of about 25 mm. As you can see, it can be made from ordinary sheet, cardboard and superglue. now we will fix the beginning of the skein on the frame and relax - we will need to make about 550 revolutions, no matter in which addition. I made 12 layers, which took me 1.5 hours.

Step 3: Splicing

We solder everything according to the scheme, without any nuances. The Hall sensor is soldered to the wires as it will be placed on the spool. When everything is soldered, place the sensor in the coil, secure it, hang the coil and apply current. When you hold up the magnet, you will feel that it is attracted or repulsed, depending on the pole, and tries to hover in the air, but fails.

Step 4: setup

After 30 minutes spent on solving the question, "why does this thing not work?" The spec included pictures showing which side is sensitive.

By pulling out the sensor and bending it so that flat side with the inscriptions was parallel to the ground, I returned it to its place - the improvised device began to work much better, but the magnet still did not levitate. We managed to understand what the problem was rather quickly: a magnet in the form of a tablet is not the best example for levitation. It was enough to shift the center of gravity to the bottom of the magnet (I did this with a piece of thick paper). By the way, don't forget to check which side of the magnet is attracted to the coil. Now everything worked more or less normally and all that was left was to fix and protect the sensor.

What other nuances are there in this project? At first I wanted to use a 12V adapter, but the electromagnet quickly warmed up, and I had to switch it to 5V, I did not notice any deterioration in operation, and the heating was practically eliminated. The diode and limiting resistor were turned off almost immediately. I also removed the blue paper from the reel - the coils of copper wire look much nicer.

Step 5: the final

DIY or do it yourself

0.Preface

I read all sorts of internet here and decided to build my own Levitron, without any digital nonsense. No sooner said than done. I spread the torment of creativity for everyone to see.

1.Brief description

The Levitron is a device that keeps an object in balance with the forces of gravity using a magnetic field. It has long been known that it is impossible to levitate an object using static magnetic fields. In school physics, this was called a state of unstable equilibrium, as far as I remember. However, with a little desire, knowledge, effort, money and time, it is possible to levitate an object dynamically by using electronics as feedback.

Here's what happened:

2.Functional circuit

Electro-magnetic sensors located at the ends of the coil produce a voltage proportional to the level of magnetic induction. In the absence of an external magnetic field, these voltages will be the same regardless of the magnitude of the coil current.

In the presence of a permanent magnet near the lower sensor, the control unit will generate a signal proportional to the field of the magnet, amplify it to the desired level and transmit it to the PWM to control the current through the coil. Thus, feedback occurs and the coil will generate a magnetic field that will keep the magnet in equilibrium with the forces of gravity.

Something worked out cleverly, I'll try it differently:
- There is no magnet - the induction at the ends of the coil is the same - the signal from the sensors is the same - the control unit gives out a minimum signal - the coil works at full power;
- They brought a magnet close - the induction is very different - the signals from the sensors are very different - the control unit gives out the maximum signal - the coil turns off completely - no one holds the magnet and it starts to fall;
- Manit falls - moves away from the coil - the difference in signals from the sensors decreases - the control unit decreases the output signal - the current through the coil increases - the induction of the coil increases - the magnet begins to attract;
- Beckons attracts - approaches the coil - the difference in signals from the sensors increases - the control unit increases the output signal - the current through the coil decreases - the induction of the coil decreases - the magnet begins to fall;
- Miracle - the magnet does not fall and does not attract - or rather, it falls and attracts several thousand times per second - that is, a dynamic equilibrium arises - the magnet simply hangs in the air.

3.Construction

The main structural element is an electro-magnetic coil (solenoid), which holds with its field permanent magnet.

On the plastic frame D36x48, 78 meters of copper enameled wire with a diameter of 0.6 mm is tightly wound, it turned out about 600 turns. According to calculations, with a resistance of 4.8 Ohm and a 12V power supply, the current will be 2.5A, the power is 30W. This is necessary for the selection external block nutrition. (In fact, it turned out 6.0 Ohm, it is unlikely that they cut more wires, rather they saved on the diameter.)

A steel core is inserted inside the coil from door hinge diameter 20mm. At its ends, sensors are fixed with hot glue, which must be oriented in the same direction.

The coil with sensors is mounted on an aluminum strip bracket, which in turn is attached to the body, inside of which is the control board.

The housing contains an LED, a switch and a power socket.

The external power supply unit (GA-1040U) is taken with a power reserve and provides a current of up to 3.2A at 12V.

The N35H magnet D15x5 with a glued Coca-Cola can is used as a levitating object. I must say right away that a full can is not good, so we make holes at the ends with a thin drill, drain the valuable drink (you can drink it if you are not afraid of shavings) and glue a magnet to the top ring.

4 schematic diagram

The signals from the U1 and U2 sensors are fed to an operational amplifier OP1 / 4, connected in a differential circuit. The upper U1 sensor is connected to the inverting input, the lower U2 to the non-inverting one, that is, the signals are subtracted, and at the OP1 / 4 output we get a voltage proportional only to the level of magnetic induction created by a permanent magnet near the lower U2 sensor.

The combination of C1, R6 and R7 elements is the highlight of this circuit and allows you to achieve the effect of complete stability, the magnet will hang rooted to the spot. How it works? The constant component of the signal passes through the R6R7 divider and is attenuated 11 times. The variable component passes through the C1R7 filter without attenuation. Where does the variable component come from? The constant part depends on the position of the magnet near the lower sensor, the variable part arises from the oscillations of the magnet around the equilibrium point, i.e. from a change in position in time, i.e. from speed. It is interesting for us that the magnet is stationary, i.e. its speed was equal to 0. Thus, in the control signal we have two components - the constant is responsible for the position, and the variable is responsible for the stability of this position.
Further, the prepared signal is amplified by OP1 / 3. The variable resistor P2 is used to set the required gain during the tuning phase to achieve balance, depending on the specific parameters of the magnet and coil.

A simple comparator is assembled on OP1 / 1, which turns off the PWM and, accordingly, the coil when there is no magnet nearby. Highly convenient thing, do not remove the power supply from the socket if the magnet is removed. The trigger level is set by the variable resistor P1.

Next, the control signal is fed to the pulse width modulator U3. The output voltage swing is 12V, the frequency of the output pulses is set by the ratings C2, R10 and P3, and the duty cycle depends on the level of the input signal at the DTC input.
PWM controls the switching of the power transistor T1, which, in turn, controls the current through the coil.

The LED1 LED may not be installed, but the SD1 diode is required to drain excess current and avoid overvoltage when the coil is turned off due to the phenomenon of self-induction.

NL1 is our homemade coil, to which a separate section is devoted.

As a result, in equilibrium mode, the picture will be something like this: U1_OUT = 2.9V, U2_OUT = 3.6V, OP1 / 4_OUT = 0.7V, U3_IN = 1.8V, T1_OPEN = 25%, NL1_CURR = 0.5A.

For clarity, I attach graphs of the transfer characteristic, frequency response and phase response, and the oscillogram at the output of the PWM and the coil.

5.Selection of components

The device is assembled from inexpensive and affordable components. The most expensive was the copper wire WIK06N, for 78 meters WIK06N paid 1200 rubles, everything else taken together was much cheaper. There is generally a wide field for experiments, you can do without a core, you can take a thinner wire. The main thing is not to forget that the induction along the axis of the coil depends on the number of turns, the current through them and the geometry of the coil.

Analogue Hall sensors SS496A with a linear characteristic up to 840G are used as magnetic field sensors U1 and U2, this is the same for our case. When using analogs with a different sensitivity, you will need to adjust the gain at OP1 / 3, as well as check for the maximum induction level at the ends of your coil (in our case with a core, it reaches 500G) so that the sensors do not saturate at peak load.

OP1 is an LM324N quad operational amplifier. When the coil is off, it gives out 20mV instead of zero at the 14th output, but this is quite acceptable. The main thing is not to forget to choose from a bunch of 100K resistors the closest in actual value to be installed as R1, R2, R3, R4.

C1, R6 and R7 are chosen by trial and error as the most the best option to stabilize magnets of different calibers (N35H magnets D27x8, D15x5 and D12x3 were tested). The R6 / R7 ratio can be left as is, and the C1 rating can be increased to 2-5 μF in case of problems.

When using very small magnets, you may lack the gain, in this case, reduce the R8 rating to 500 ohms.

D1 and D2 are ordinary rectifier diodes 1N4001, any will do here.

The popular TL494CN microcircuit is used as a pulse-width modulator U3. The operating frequency is set by elements C2, R10 and P3 (according to the 20 kHz scheme). Optimal range 20-30 kHz, at a lower frequency, the whistle of the coil appears. Instead of R10 and P3, you can simply put a 5.6K resistor.

T1 is a field-effect transistor IRFZ44N, any other from the same series will do. When choosing other transistors, it may be necessary to install a radiator, be guided by the minimum values of the channel resistance and gate charge.
SD1 is a VS-25CTQ045 Schottky diode, here I grabbed with a large margin, a normal high-speed diode will do, but it may get very hot.

LED1 yellow LED L-63YT, here, as they say, the taste and color, you can instruct them more so that everything shines with colorful lights.

U4 is a 5V L78L05ACZ voltage regulator for powering sensors and an operational amplifier. When using an external power supply with an additional 5V output, you can do without it, but it is better to leave the capacitors.

6.Conclusion

Everything worked out as planned. The device works stably around the clock, consumes only 6W. Neither the diode, nor the coil, nor the transistor heat up. I attach a couple more photos and the final video:

7. Disclaimer

I am not an electronics engineer or a writer, I just decided to share my experience. Maybe something will seem too obvious to you, and something too complicated, but forgot to mention something altogether. Feel free to make constructive suggestions both for the text and for improving the scheme so that people can easily repeat it if they wish.

The principle of operation of the Levitron toy, which clearly demonstrates the state of weightlessness, is based on the action of a magnetic field that holds small objects in the air.

Unfortunately, such toys are not yet produced by the domestic industry, so the demand for them cannot be satisfied. There is, of course, an opportunity to order a Levitron from abroad, but the cost of the toy (already quite high - $ 35) significantly increases due to the cost of delivery.

But on the other hand, nothing can prevent you from making a Levitron with your own hands one of two known methods: on an electromagnet or on permanent magnets.

The second of these methods is much simpler than the first, besides, specific knowledge in the field of physics is not required, and besides power supply this device is also not needed.

Materials for making Levitron

So, we need three magnets in the form of rings with sufficient power to make a toy. Magnets from woofers, which have long expired, are quite suitable for our purpose.

In order to make a top, you will need a neodymium magnet. You can take it from the speaker, which has the inscription "Neodium transducer". Similar speakers are used in cell phones. The strongest permanent magnet today is neodymium, made from an alloy of neodymium, boron and iron. High temperature will negatively affect it, therefore this magnet should be protected from heating. So a magnet from cell phone can be of two types - in the form of a round plate or in the form of a ring. The ring magnet is put on the top of the top, strictly in the center, and the magnet in the form of a tablet is glued to the axis of the top from the bottom. The material for the top itself should be a light material such as composite or plastic.

Setting up the Levitron

Setting up should be approached with special meticulousness, because this part of the work is crucial and is the most time consuming. Ring magnets must be connected with opposite polarities. A plate (not made of metal) with a thickness of up to 1 cm should be installed on top of them. The top will be neatly installed in the base of the Levitron - the center of the magnet. If you notice that the top is tilting to the side, then the magnet needs to be replaced with another one with a larger diameter.

To start the top, you will need a few more elements with which you can adjust the thickness of the platform in order to achieve normal rotation of the top. We need plexiglass plastic with paper sheets. If the top is spinning normally, we begin to smoothly raise the platform until it flies up.

If our top flies up too quickly, we should increase its weight. If it deviates in one direction, then the situation can be corrected by placing paper sheets under the opposite one. These steps allow us to adjust the base of our toy so that it is clearly at sea level.

The idea of this lesson was inspired by the project of the Kickstarter crowdfunding platform called "Air Bonsai", really beautiful and mysterious, which was made by the Japanese.

But any mystery can be explained if you look inside. In fact, it is magnetic levitation, when there is an object levitating from above and an electromagnet controlled by the circuit. Let's try to implement this mysterious project together.

We found out that the Kickstarter circuitry was quite complex, without any microcontroller. There was no way to find her analog circuit. In fact, if you look more closely, the principle of levitation is pretty simple. You need to make a magnetic piece "float" over another magnetic piece. The main further work was to prevent the levitating magnet from falling.

It has also been suggested that doing this with an Arduino is actually much easier than trying to understand the schematic of a Japanese device. In fact, everything turned out to be much simpler.

Magnetic levitation consists of two parts: a base part and a floating (levitating) part.

Base

This part is at the bottom, which consists of a magnet to create a circular magnetic field and electromagnets to control this magnetic field.

Each magnet has two poles: north and south. Experiments show that opposites attract and the same poles repel. Four cylindrical magnets are placed in a square and have the same polarity, forming a circular magnetic field upward to push out any magnet that has the same pole in between.

There are four electromagnets in general, they are placed in a square, two symmetrical magnets are a pair, and their magnetic field is always opposite. The Hall sensor and circuit drive electromagnets. We create opposite poles on electromagnets by current through them.

Floating part

The part includes a magnet floating above the base that can carry a small plant pot or other items.

The magnet from above is lifted by the magnetic field of the lower magnets because they have the same poles. However, as a rule, he tends to fall and be attracted to each other. To prevent the top of the magnet from flipping and falling, the electromagnets will create magnetic fields to push or pull to balance the floating section, thanks to the Hall effect sensor. The electromagnets are controlled by two axes X and Y, resulting in the top magnet being kept balanced and floating.

Controlling electromagnets is not easy and requires a PID controller, which is discussed in detail in the next step.

Step 2: PID controller (PID)

From Wikipedia: "A proportional-integral-differentiating (PID) controller is a device in a control loop with feedback. It is used in automatic control systems to generate a control signal in order to obtain the required accuracy and quality of the transient process. The PID controller generates a control signal, which is a sum three terms, the first of which is proportional to the difference between the input signal and the feedback signal (error signal), the second is the integral of the error signal, and the third is the derivative of the error signal. "

In simple terms: “The PID controller calculates the 'error' value as the difference between the measured [Input] and the desired setting. The controller tries to minimize the error by adjusting [output]. "

So you tell the PID what to measure (Input), what value you want, and a variable that will help that value out. The PID controller then adjusts the output to make the input equal to the setting.

For example: in the car, we have three values (Input, Installation, Output) - the speed, the desired speed and the angle of the accelerator pedal, respectively.

In this project:

The input is the real time value from the hall sensor, which is updated continuously as the position of the floating magnet will change in real time.
The setpoint is the value from the hall sensor, which is measured when the floating magnet is in the balance position, in the center of the base of the magnets. This index is fixed and does not change over time.
The output signal is the speed for controlling the electromagnets.

Thanks to the Arduino community for writing a PID library that is very easy to use. Additional Information The Arduino PID is available on the Arduino official website. We need to use a pair of Arduino PID controllers, one for the X-axis and one for the Y-axis.

Step 3: accessories

The list of accessories for the lesson turns out to be decent. Below is a list of the components you should buy for this project, make sure you have everything before starting. Some of the components are very popular and you will probably find them in your own warehouse or home.

Step 4: Tools

Here is a list of the most commonly used tools:

Soldering iron
Hand saw
Multimeter
Drill
Oscilloscope (optional, you can use a multimeter)
Table drill
Hot glue
Pliers

Step 5: LM324 Op-amp, L298N driver and SS495a

LM324 Op-amp

Operational amplifiers (op-amps) are some of the most important, widely used and versatile circuits in use today.

We use an op-amp to amplify the signal from the Hall sensor, the purpose of which is to increase the sensitivity so that the arduino can easily recognize the changing magnetic field. Changing a few mV at the output of the hall sensor, after passing through the amplifier, can change by several hundred units in the Arduino. This is necessary to ensure smooth and stable operation of the PID controller.

The common op amp we chose is the LM324, it's cheap and you can buy it from any electronics store. The LM324 has 4 internal amplifiers that allow it to be used flexibly, however only two amplifiers are needed in this project, one for the X-axis and one for the Y-axis.

L298N module

L298N double H-bridge is commonly used to control the speed and direction of two motors direct current or easily controls one bipolar stepper motor... The L298N can be used with 5 to 35 VDC motors.

There is also a built-in 5V regulator, so if the supply voltage is up to 12V, you can also connect the 5V power supply from the board.

This project uses the L298N to drive two pairs of solenoid coils and uses the 5V output to power the Arduino and the hall sensor.

Pinout of modules:

Out 2: pair of electromagnets X
Out 3: pair of electromagnets Y
Power input: DC 12V input
GND: Ground
5v output: 5v for Arduino sensors and hall
EnA: Enables the PWM signal for output 2
In1: Enable for output 2
In2: Enable for Out 2
In3: Enable for output 3
In4: Enable for output 3
EnB: Enables PWM signal for Out3

Arduino connection: we need to remove 2 jumpers in pins EnA and EnB, then connect 6 pins In1, In2, In3, In4, EnA, EnB to Arduino.

SS495a Hall Sensor

SS495a is a linear Hall effect sensor with analog output. Please note the difference between analog output and digital output, you cannot use a sensor with digital output in this project, it only has two states 1 or 0, so you cannot measure the output of magnetic fields.

The analog sensor will result in a voltage range of 250 to Vcc, which you can read with the Arduino analog input. Two hall sensors are required to measure the magnetic field in both the X and Y axes.

Step 6: NdFeB (neodymium-iron-boron) neodymium magnets

From Wikipedia: "Neodymium - chemical element, a rare earth metal, silvery white with a golden tint. Belongs to the group of lanthanides. Oxidizes easily in air. Discovered in 1885 by the Austrian chemist Karl Auer von Welsbach. It is used as a component of alloys with aluminum and magnesium for aircraft and rocketry. "

Neodymium is a metal that is ferromagnetic (in particular, it exhibits antiferromagnetic properties), which means that, like iron, it can be magnetized to become a magnet. But its Curie temperature is 19K (-254 ° C), therefore, in its pure form, its magnetism manifests itself only at extremely low temperatures... However, neodymium compounds with transition metals such as iron can have Curie temperatures significantly higher room temperature and they are used to make neodymium magnets.

Strong is the word used to describe a neodymium magnet. You cannot use ferrite magnets because their magnetism is too weak. Neodymium magnets are much more expensive than ferrite magnets. Small magnets are used for the base, large magnets for the floating / levitating part.

Attention! You need to be careful when using neodymium magnets as their strong magnetism can harm you or they can break your data. hard disk or others electronic devices influenced by magnetic fields.

Advice! You can separate two magnets by pulling them horizontally, you cannot separate them in the opposite direction because their magnetic field is too strong. They are also very fragile and break easily.

Step 7: prepare the base

Used a small terracotta pot, which is commonly used for growing succulents or cactus. You can also use a ceramic pot or wooden pot, if appropriate. Use an 8mm drill bit to create a hole in the bottom of the pot that is used to hold the DC jack.

Step 8: 3D print the floating part

If you have a 3D printer, great. You have the ability to do everything with it. If there is no printer, do not despair, because you can use the cheap 3D printing service that is very popular right now.

For laser cutting files are also in the archive above - file AcrylicLaserCut.dwg (this is autocad). The acrylic piece is used to support the magnets and electromagnets, the rest is used to cover the surface of the terracotta pot.

Step 9: Prepare SS495a Hall Sensor Module

Cut the PCB layout in two, one to attach the hall sensor and the other to the LM324 circuit. Attach two magnetic sensors perpendicularly printed circuit board... Use thin wires to connect the two pins of the VCC sensors together, do the same with the GND pins. Output contacts are separate.

Step 10: op-amp circuit

Solder the socket and resistors to the PCB following the diagram, making sure to place the two potentiometers in the same direction for easier calibration later. Connect the LM324 to the jack, then connect the two outputs of the hall sensor module to the op-amp circuit.

Connect the two output wires of the LM324 to the Arduino. 12V input with 12V input of L298N module, 5V output of L298N module to 5V potentiometer.

Step 11: Assembling the electromagnets

Assemble the electromagnets on an acrylic sheet, they are fixed in four holes near the center. Tighten the screws to avoid movement. Since the electromagnets are centrally symmetrical, they are always opposite the poles, so that the wires on the inside of the electromagnets are connected together, and the wires on outside electromagnets are connected to L298N.

Pull the wires under the acrylic sheet through the adjacent holes to connect to the L298N. The copper wire is covered with an insulated layer, so you must remove it with a knife before you can solder them together.

Step 12: sensor module and magnets

Use hot glue to fix the sensor module between the electromagnets, note that each sensor should be square with two electromagnets, one on the front and one on the back. Try to calibrate the two sensors as centrally as possible so they don't overlap, which will make the sensor most efficient.

The next step is to collect the magnets on acrylic base... By combining two D15 * 4mm magnets and a D15 * 3mm magnet together to form a cylinder, this will make the magnets and electromagnets have the same height. Assemble the magnets between the pairs of electromagnets, note that the poles of the upward magnets must be the same.

Step 13: DC power connector and L298N 5V output

Solder the DC power jack with two wires and use heat shrink tubing. Connected DC power connector to the input of the L298N module, its 5V output will supply power to the Arduino.

Step 14: L298N and Arduino

Connect L298N module to Arduino following the diagram above:

L298N → Arduino
5V → VCC
GND → GND
EnA → 7
B1 → 6
B2 → 5
B3 → 4
B4 → 3
EnB → 2

Step 15: Arduino Pro Mini programmer

Since the Arduino pro mini does not have a USB serial port, you need to connect an external programmer. FTDI Basic will be used to program (and power) the Pro Mini.

Levitron, as you know, is a top spinning in air above a box in which a magnetic field source acts. Levitron can be made from the popular hall sensor.

What is Levitron

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Levitron is a toy. There is no point in buying it if you know the manufacturing options homemade device... There will be nothing complicated in the design of such a Levitron, if there is conventional sensor hall, for example, bought for a car distributor, and left for future use.

You should be aware that the effect of levitation is always observed in a fairly narrow zone. Such realities somewhat limit the freedom of action of the craftsmen, however, with the application of patience and time, you can always configure the Levitron efficiently and efficiently. He will practically not fall or jump.

Hall sensor Levitron

Levitron for a hall sensor and the idea of \ u200b \ u200bmaking it is simple, like everything ingenious. Due to the strength of the magnetic field, a piece of any material with electromagnetic properties rises into the air.

To create the effect of "hovering", soaring in the air, the connection is carried out with a high frequency. In other words, the magnetic field, as it were, lifts and throws the material.

The scheme of the device is too simple, and even a schoolboy who has not sat through physics lessons in vain will be able to build everything on his own.

We need an LED (its color is selected depending on individual preferences).
RFZ 44N transistors (although any field device close to these parameters will do).
Diode 1N 4007.
1k ohm and 330 ohm resistors.
Actually, the hall sensor itself (A3144 or other).
Copper winding wire 0.3-0.4 mm in size (about 20 meters will be sufficient).
Neodymium magnet in the form of a 5x1 mm tablet.
5-volt charger designed for a mobile phone.

Now, in detail about how the assembly is carried out:

A frame for the electromagnet is made with exactly the same parameters as in the photo. 6 mm - diameter, about 23 mm - winding length, 25 mm - cheek diameter with a margin. A frame is made of cardboard and a regular notebook sheet, using superglue.

End copper wire is fixed on the spool, and then winding is carried out (about 550 turns). It does not matter in which direction to wind. The other end of the wire is also secured, while the coil is set aside.
We solder everything according to the scheme.

The hall sensor is soldered onto the wiring and then put on the coil. It is necessary to insert it inside the coil, fix it with improvised means.

Attention. The sensitive area of the sensor (you can determine it from the documentation for the hall sensor) must be parallel to the ground. Therefore, it is recommended to bend this place slightly before inserting the sensor into the coil.

The coil is suspended, it is powered through the previously soldered board. The coil is fixed with a tripod.

Now you can check how the Levitron works. Any electrified material can be brought to the coil from below. It will either be attracted by the coil or repelled, depending on the polarity. But we need the material to hang in the air, float. This will be so if the shape of the material is not too small in relation to the coil.

Note. If the pill magnet is small, it will not levitate very effectively. It may fall. To eliminate flaws in the work, it is necessary to shift the center of gravity of the material to the bottom - an ordinary piece of paper is suitable as a load.

As for the LED, you don't need to install it. On the other hand, if you want more effect, you can organize a backlit show.

Homemade Levitron in classic design without sensor

As you can see, thanks to the presence of the hall sensor, it was possible to make a quite spectacular toy. However, this does not mean at all that you cannot do without a sensor. On the contrary, a home-made Levitron in a classic design, it is just a large magnet from the speaker (13-15 cm in diameter) and a small ring magnet for a top (2-3 cm in diameter), without using a sensor.

The axis of the top is made, as a rule, of old pen or a pencil. The main thing is that the rod is selected so that it fits snugly in the center of the ring magnet. The excess part of the handle is then cut off (about 10 cm in length, together with the attached magnet for the top, that's what you need).

The classic Levitron manufacturing scheme also implies the presence of a dozen different washers cut from thick paper. What are they needed for? If in the above case, paper was also used, and as we remember - to shift the center of gravity down or, more simply, for adjustment. It's the same here. The washers will be needed for the ideal setting of the top (if necessary, they are planted after the ring magnet on the rod).

Attention. In order for a homemade top to levitate perfectly, in addition to adjusting with washers, you must not be mistaken with the polarity. In other words, align the ring magnet in alignment with the large magnet.

But that's not all. Both in the first case (using a hall sensor) and in the second, it is necessary to achieve the ideal evenness of the source of attraction. In other words, put a large magnet on perfectly flat surface... To achieve this, apply wooden coasters of various thicknesses. If the magnet does not sit evenly, the stands are placed on one side or on several sides, thus evenness is adjusted.

Platform Levitrons

The platform scheme of the Levitron is distinguished, as a rule, by the presence of not one, but several source magnets. In this case, a material or a top floating in the air will tend to fall onto one of the magnets, displaced from the vertical axis. To avoid this, you must be able to adjust the central gravity zone, and do it perfectly accurately.

And here the same coils come to the rescue, with a hall sensor inserted inside. Let there be two such coils, and they should be placed exactly in the middle of the platform, between the magnets. On the diagram, it will look like this (1 and 2 are magnets).

From the diagram, it becomes clear that the purpose of controlling the coils is to create a horizontal force, a center of gravity. This force is formally called Fss, and it is directed to the equilibrium axis when a displacement occurs, indicated in the diagram as X.

If you connect the coils so that the pulse creates a zone with reversed polarity, then the issue with the bias can be solved. Any physicist will confirm this.

Any old DVD player is selected as a case for the construction of the platform Levitron. All "insides" are removed from it, magnets and coils are installed, and for the sake of beauty, the upper part is closed with a practical cover made of thin, possibly transparent material (which allows a magnetic field to pass through).

Hall sensors should protrude through the openings of the platform, should be soldered on the unbent connector legs.

As for the magnets, these can be round elements with a thickness of 4 mm. It is desirable that one of the magnets is larger than the second in diameter. For example, 25 and 30 mm.

There are also more complex versions of Levitrons, made according to the scheme of unwinding a top located inside a small globe. These levitrons can also be built using hall sensors - effective components that have revolutionized the automotive industry and other areas of human activity.