Homemade levitron ("UFO prototype") for the very strong in physics and electronics. Analog Levitron on PWM Snake Levitron how it works
A short video about what the made levitron is like:
www.youtube.com/watch?feature=player_embedded&v=vypjmqq9...
If someone is not afraid to do the same interesting thing, then here you are detailed instructions:
A bit of theory
Let's start, perhaps, with the mechanical scheme of the platform levitron, which has developed in my understanding. The magnet that hovers above the platform, I will here for brevity call the word "chip".
Levitron platform sketch(top) is shown in Fig. 1.
On fig. 2 - power diagram of a vertical section along the central axis of the platform (as I imagine it) at rest and without current in the coils. All is well, except that the state of rest in such a system is unstable. The chip tends to move away from the vertical axis of the system and slam onto one of the magnets with force. When "feeling" the space above the magnets with a chip, a force "hump" is felt above the center of the platform with the top lying on the central axis.
mg - chip weight,
F1 and F2 - the forces of interaction of the chip with the magnets of the platform,
Fmag - the total impact that balances the weight of the chip,
DH - Hall sensors.
On fig. 3. shows the interaction of the chip with the coils (again, in my opinion), and the rest of the forces are omitted.
Figure 3 shows that the purpose of coil control is to create a horizontal force Fss, always directed towards the equilibrium axis when a displacement occurs. X. To do this, it is enough to turn on the coils so that the same current in them creates a magnetic field in the opposite direction. There was nothing left: measure the offset of the chip from the axis (the value X) and determine the direction of this displacement using Hall sensors, and then pass currents in the coils of a suitable strength.
Simple repeat electronic circuits- not in our traditions, especially since:
- two TDA2030A are not available, but there is a TDA1552Q;
- there are no SS496 Hall sensors (available for about $2 each), but there are sensors similar to HW101, 3 pcs for free in each CD or DVD drive drive;
- too lazy to mess with bipolar power.
Datasheets:
SS496 - http://sccatalog.honeywell.com/pdbdownload/images/ss496.seri...HW101- http://www.alldatasheet.com/datasheet-pdf/pdf/143838/ETC1/HW101A.html
The circuit consists of two identical amplifying channels with differential inputs and bridged outputs. On fig. 4 shows the complete diagram of only one amplification channel. The chips used were LM358 (http://www.ti.com/lit/ds/symlink/lm158-n.pdf) and TDA1552Q (http://www.nxp.com/documents/data_sheet/TDA1552Q_CNV.pdf).
A pair of Hall sensors is connected to the input of each channel so as to supply a differential signal to the amplifier. The outputs of the sensors are switched on in opposite directions. This means that when a pair of sensors is in a magnetic field with the same intensity, zero differential voltage is supplied from it to the input of the amplifier.
Balancing resistors R10 are multi-turn, old, Soviet ones.
In an attempt to squeeze a sufficiently high gain out of the amplifier, I got a banal self-excitation, presumably due to a mess on the circuit board. Instead of “cleaning”, frequency-dependent RC chains R15C2 are introduced into the circuit; they are not required. If you still had to install them, then the resistance R15 must be selected as the largest, at which self-excitation goes out.
The power supply of the entire device is an adapter (pulse) for 12V 1.2A, reconfigured to 15V. Power consumption in normal condition(with the fan turned off) in the end turned out to be quite modest: 210-220 mA.
Design
A 3.5” floppy drive shroud was chosen as the case, which roughly corresponds to the dimensions of the prototypes. To level the platform
legs are made of M3 screws.
A figured hole is cut out in the upper part of the body, clearly visible in Fig. 5. Subsequently, it is closed with a decorative mirror plate made of chrome-plated brass, fixed with screws from hard drives.
1 - installation locations for magnets (bottom) and balance indicators (optional)
2 - "pole pieces" of coils
3 - Hall sensors
4 - backlight LEDs (optional)
Hall sensors are located in the holes of the fiberglass base of the platform and are soldered on the unbent legs of the connectors (I don’t know the type). The connectors looked like in Fig.6.
The sensors are soldered from the motors of the CD or DVD drive. There they are located under the edge of the rotor and are clearly visible in Fig. 7. For one channel, you need to take a pair of sensors from one engine - so they will be the most identical. Soldered sensors - in Fig.8.
For coils, plastic spools were purchased for sewing machines, but there was little room for winding on them. Then cheeks were cut off from the spools and glued to pieces of thin-walled brass tube outer diameter 6mm and length 14mm. The tube used to be a segment of a telescopic rod antenna. On four such frames with a 0.3 mm wire, the windings are wound “almost in layers” (without fanaticism!) Until they are filled. The resistance is aligned to 13 ohms.
Magnets - rectangular 20x10x5 mm and disk magnets with a diameter of 25 and 30 mm 4 mm thick (Fig. 9) - I still had to buy ... Rectangular magnets are installed under the base of the platform, and chips are made from disk magnets.
View of the device from below and behind (upside down) - in fig. 10 and 11 (one legend for both figures). The mess, of course, is picturesque ...
The U2 TDA1552Q chip (3) is located on the heat sink (9), which used to work on the video card. The radiator itself is fixed with screws on the bent parts of the top case cover. A power socket (1), control sockets (2) and a thermal control unit (5) are also fixed to the radiator (9).
A piece of fiberglass, which used to be a keyboard, serves as the base of the platform. Coils (7) are fixed on the base with M4 screws and nuts. Magnets (6) are fixed on it with the help of clamps and self-tapping screws.
The control jacks (2) are made from a computer power connector and are fixed on the back of the device near the balancing resistors (10) so that they are easily accessible without disassembly. The jacks are connected, of course, to the outputs of both channels of the amplifier.
The circuitry of the preamplifier and its power regulator, including balancing resistors (10), is mounted on breadboard and as a result of the adjustment turned into a picturesque pigsty, macro photography of which had to be refrained from.
1 - fastening the power socket
2 - control sockets
3 - TDA1552Q
4 - power switch
5 - thermal control unit
6 - magnets under the clamps
7 - coils
8 - magnetic shunts
9 - heat sink
10 - balancing resistors
Adjustment
Setting zeros at the outputs of both channels at each debugging start is mandatory. It is possible without fanaticism: + -20 mV is quite acceptable accuracy. There may be some interference between the channels, so with a significant initial deviation (more than 1-1.5 volts at the channel output), it is better to set zeros twice. It is worth remembering that with an iron case, the balance of a disassembled and assembled device is two big differences.
Checking channel phasing
The chip must be taken in hand and placed above the center of the platform of the included Levitron at a height of approximately 10-12mm. Channels are checked one by one and separately. When the chip is shifted by hand along the line connecting the sensors opposite from the center, the hand should feel a noticeable resistance created by magnetic field coils. If no resistance is felt, and the hand with the chip "blows" away from the axis, you need to swap the wires from the output of the channel under test.
Adjusting the position of the floating chip
On videos about homemade platform levitrons, you can often see that the chip is hovering in an inclined position, even if it is made on the basis of disk magnets, that is, it is quite well symmetrical. Not without distortion in the described design. Perhaps the metal case is to blame ...
First thought: move the magnets down from the side where the chip is unnecessarily “supported”.
The second thought: move the magnets further from the center from the side where the chip is unnecessarily “supported”.
The third thought: if the magnets are displaced, then the magnetic axis of the system of permanent magnets of the platform will be skewed relative to the magnetic axis of the coil system, due to which the behavior of the chip will become unpredictable (especially with different weights).
The fourth thought - to make the magnets stronger on the side where the chip is tilted - was discarded as unrealizable, because there was nowhere to get a wide range of magnets to fit.
The fifth idea: to make the magnets weaker on the side where the chip is unnecessarily “supported” – turned out to be successful. Moreover, it is quite simple to implement. A magnet, as a source of a magnetic field, can be shunted, that is, short-circuited part magnetic flux, so that in the surrounding space the magnetic field will become slightly weaker. As magnetic shunts, small ferrite rings (10x6x3, 8x4x2, etc.) were used, plucked free of charge from dead economy lamps (8 in Fig. 10). These rings just need to be magnetized to a too strong magnet (or two or three) on the side that is farther from the center of the platform. It turned out that by choosing the number and size of shunts for each "too strong" magnet, it is possible to quite accurately level the position of a floating symmetrical chip. Don't forget to perform electrical balancing after every change in the magnetic system!
Options
Options include: amplifier unbalance indicators, thermal control unit, lighting, and adjustable platform feet.
The amplifier unbalance indicators are two pairs of LEDs located at the same radii as the sensors, in the thickness of the fiberglass base of the platform (1 in Fig. 5). LEDs, very small and flat, used to work in some kind of modem, but they will also work from an old mobile phone (in SMD version). The LEDs are recessed in the holes, since the chip, breaking off from the center, flops onto the nearest magnet and is quite capable of destroying the LED.
The indicator scheme for one channel is shown in fig. 12. LEDs must be with an operating voltage of 1.1-1.2 V, i.e. simple red, orange, yellow. At higher LED voltages (2.9-3.3 V for super-bright ones), the number of diodes in the D3-D6 chain should be recalculated to minimize the "dead zone" - the minimum voltage at the channel output, at which none of the LEDs glows.
I arranged the indicators so that the one towards which the chip is shifted from the center shone. Indicators help to easily hang a chip over the Levitron, as well as to level the platform. In the normal state, they are all redeemed.
The diagram of the thermal control unit is in fig. 13. Its purpose is to prevent the final amplifier from overheating. At the output of the thermal unit, a fan 50x50 mm 12V 0.13A from the computer is turned on.
In the thermal node circuit, it is easy to recognize a slightly modified Schmitt trigger. Instead of the first transistor, a TL431 chip was used. The type of transistor Q1 is indicated conditionally - I stuck the first NPN that came across that could withstand the operating current of the fan. As a temperature sensor, a thermistor found on an old motherboard on the processor socket. The temperature sensor is glued to the heatsink of the final amplifier. By selecting the resistor R1, you can adjust the thermal unit for operation at a temperature of 50-60C. Resistor R5, together with the collector current Q1, determines the amount of hysteresis in the circuit relative to the voltage at the control input U1.
In the diagram in fig. 13 resistor R7 is introduced to reduce the voltage on the fan and, accordingly, the noise from it.
On fig. 14 shows how the fan is embedded in the bottom cover of the case.
Another way to use a thermal node is to connect a final amplifier chip to the MUTE control pin (Fig. 15). The value of the R5 rating indicated on the diagram assumes that MUTE (pin 11 of the U2 chip in Fig. 4) is connected to the power supply through a 1kΩ resistor (NOT directly, as in the datasheet!). In this case, a fan is not needed. True, when the MUTE signal is applied to the amplifier, the chip falls, and after the MUTE signal is removed, it itself (for some reason?) does not take off.
Illumination - 4 bright LEDs with a diameter of 3mm, located obliquely to the center in the holes of the platform base and decorative plate in those places where the chip does not fall. They are connected in series and through a 150 Ohm resistor to the 15V device's general power supply circuit.
Conclusion
load capacity
In order to “finish off” the topic, the “cargo characteristics” of the Levitron with chips of 25 and 30 mm in diameter were removed. I here called the cargo characteristics the dependence of the height of the hovering of the chip above the platform (from the decorative plate) on the total weight of the chip.
For a chip with a 25 mm magnet and a total weight of 19 g, the maximum height was 16 mm, and the minimum was 8 mm with a weight of 38 g. Between these points, the characteristic is almost linear. For a chip with a 30 mm magnet, the load characteristic turned out to be between the points of 16 mm at 24g and 8 mm at 48g.
From a height below 8 mm from the platform, the chip falls, being attracted to the iron cores of the coils.
DO NOT do like me!
First, do not save on sensors. "Naked" Hall sensors, taken out in pairs for each channel of two engines (that is, almost identical!) - still show their ugly large temperature coefficient of resistance. Even with the same power circuits and back-to-back switching of the sensor outputs, you can get a noticeable zero shift at the channel output when the temperature changes. Integrated sensors SS496 (SS495) have not only a built-in amplifier, but also thermal stabilization. The internal amplifier of the sensors will make it possible to significantly increase the overall gain of the channels, and the circuit for their power supply is simpler.
Secondly, one should, if possible, refrain from placing the Levitron in an iron case.
Thirdly, bipolar power is still preferable, because gain control and zero adjustment are easier.
Thank you for your attention!
Asked to give you New Year Anti-gravity Santa Claus should not answer "Mission Impossible". Hear such an answer, know - Grandfather is fake. Because scientific toys with anti-gravity elements exist and have been sold for $30-60 for several years.
There is a company in Seattle aptly named Fascinations Toys and Gifts. The charm of her products is that at first they seem unreal. True, unlike magicians, the creators of unusual souvenirs willingly reveal their secrets.
First of all, I would like to say about "Levitron" (Levitron). Before us is something like an ashtray (we will call it the base) over which a spinning top hangs in the air and spins. An anti-gravity device. Entertains "Levitron" as follows:
You take the included plate in your hand and hold it over the base. Place a spinning top on top of the plate and spin it strongly with your index and thumb.
Then the plate is slowly raised, then lowered and removed away - the gyroscope remains hanging in the air, rotating and swaying a little.
The thing is good, but practically useless on the farm (photo by hobbytron.net).
The toy does not require any electricity. Here, permanent magnets are used, placed both in the base and in the gyroscope.
From the point of view of classical physics, it is impossible to achieve the stability of two repulsive magnets, one of which floats on top of the other.
Specialists from Fascinations explain that they managed to find an exception to the rule.
More precisely, it was found by inventor Roy M. Harrigan and patented in May 1983.
As you guessed, the rotation keeps the top magnet from tipping over. But what prevents him from sliding sideways and flying off the magnetic cushion?
The lower magnet, and its field, respectively, has a complex shape. And when the top deviates from the center, a force arises that pushes it back to the equilibrium point.
It looks like "Levitron", made by hand (photo hcrs.at).
This force is very small and therefore the launch of Levitron will require training.
The balance in this system is so delicate that it is affected by the temperature in the room or even small fluctuations in the earth's magnetism.
The set of toys includes a set of 5 weights - weighing from 3 to 0.1 grams. Their combination achieves balance.
The adjustable legs of the base allow you to install it exactly horizontally, and besides, it is necessary to observe a certain orientation to the cardinal points.
Finally, the very process of lifting and removing the plate with a rotating gyroscope requires extreme caution. And the faster you can spin the top, the longer it will soar.
If the levitating top has captivated you enough, Seattle innovators are ready to offer you additional accessories for the Levitron.
For example, "Perpetuator" (Perpetuator), this time already connected to the outlet. Unlike the usual base, here are added electromagnetic fields, which keep the spinning top spinning so it can hang over your desk for weeks.
Another anti-gravity toy is called the Art Bank. This box, inside which a tennis ball, an airplane model, a coin or a candy wrapper, levitates.
In addition, there is a "flying globe" - Amazing Anti-Gravity Globes.
The anti-gravity globe is really a thing (photo fascinations.com).
Another “physical” creation of Fascinations is light and transparent waterfalls (Gosammer Falls). This is a whole collection of waterfalls, so to speak, for home and office.
They deserve mention because, unlike many analogues, they demonstrate an interesting effect.
Water flows in them wide and thin film, which never breaks, not in one place. How is this possible?
Water, pouring out even from a thin extended gap, tends to gather into a more or less compact jet, and if this is not possible, it breaks into separate streams, breaks up into drops.
Levitron is a toy that demonstrates the levitation of a spinning top in which Neodymium magnet over a ferrite magnet of a larger diameter. It looks amazing!Materials for the manufacture of Levitron
So, we need three ring-shaped magnets with sufficient power to make a toy. Magnets from low-frequency speakers, whose service life has 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. Heat will adversely affect it, so this magnet should be protected from heat. So the magnet 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 itself strictly in the center, and the tablet-shaped magnet is glued to the axis of the top from below. The material for the top itself should be lightweight material such as composite or plastic.
Levitron setting
The setting should be approached with particular scrupulousness, because this part of the work is crucial and is the most time-consuming. Ring magnets must be connected to each other by opposite polarities. A plate (not made of metal) up to 1 cm thick should be installed on top of them. The top will be carefully installed in the base of the Levitron - the center of the magnet. If you notice that the top deviates 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 will need plexiglass plastic with paper sheets. If the spinning top is spinning normally, we begin to gently raise the platform until it flies up.
If our spinning top flies up with excessive swiftness, its weight should be increased. If it deviates in one direction, then you can correct the situation by placing paper sheets under the opposite one. These actions allow you to adjust the base of our toy so that it is clearly at sea level.
And a video with levitrons ...
In some advanced stores, you can see advertising stands that show interesting effects when some thing from a shop window or an item with a brand image levitates. Sometimes rotation is added. But such an installation is quite capable of being made even by a person without much experience in homemade products. To do this, you need a neodymium magnet, which can be found in spare parts from computer equipment.
The properties of a magnet are amazing. One of these properties of repulsion by the same poles is used in objects that are used as trains on a magnetic cushion, funny toys or the basis for spectacular design objects, etc. How to make a levitating object based on magnets?
Magnetic levitation on video
Top levitation over five point neodymium magnets. Magnetic Levitation, magnétismo, magnetic experiment, truco magnética, moto perpetuo, amazing game. Entertaining physics.
Discussion
hawk
When the magnet rotates, there is levitation, and if the revolutions of the magnet decrease, it falls from orbit ... justify this effect. The interaction of magnetic fields between magnets is clear, but what is the role of rotation. You can also use an alternating magnetic field from the coils to keep the magnet in the air.
pukla777
Please work on the topic - flywheel generator. I think it will have a useful practical application. In addition, you had it filmed in a video a very long time ago, but very little and without information.
RussiaPresident
What if:
Launch this top and some kind of cube and create a Vacuum there, according to the idea there will be no air resistance and it will spin almost endlessly! And if it’s not for him to wind up the copper correctly and remove energy?
Evgeny Petrov
I read the comments, I'm surprised, what a thread!? There everything is like a magnetic top, he was given fur. energy is the constant magnetic field of the top, during the rotation of which the magnetic field also rotates, but the main thing is how! In magnets, the domains are packed unequally distributed; this is technically not possible; therefore, the passive magnet itself cannot stay on the magnetic cushion; it will go for more forte where the difference is generally negligible, so the rotation of the field does not allow this to be done.
Vyacheslav Subbotin
Another idea, but what if the laser is constantly shining from one side? Will the rotation time of the top change due to light pressure? If you take a strong laser, then it may be possible to make the top not stop at all.
Nobody Unknown
An old toy… I remember this spinning top and the plate under it on ferrite magnets, it’s already boring on neodymium, and the bottom magnet of the base was one solid plate, not five separate magnets, only it was magnetized in a tricky way…
Aligarh Leopold
Igor Beletsky, you can make a cap on which the spinning top will land, so as not to catch it. Is it possible to add a rotating magnetic field to it to keep it spinning? for example, if its magnetic table is rotated ..
Timur Aminev
And please tell us how the Earth's magnetic field slows down the top? In the sense of what moments of forces directed against rotation arise and why.
Alexander Vasilievich
If you attach a coil from above the magnet (or from below it would be even gorgeous!) And twist the top with it, then you get a kind of motor on a magnetic suspension. The thing is absolutely stupid, but beautiful. It will spin until the power supply is removed))
Ivan Petrov
Well, we've already seen this. Make the magnet levitate without spinning! (and without supports and liquid nitrogen of course).
high elf
Divorce for losers, it could be called levitation if the magnet did not have to be untwisted. The magnet itself, which is on top, will slide off if it is not given rotation.
Andrey Solomennikov
And what if you attach a fire to the platform, and propellers to the gyroscope (Yulya) that would rotate while the fire is burning below. I don’t remember the name of the engine, but its essence is the rotation, so to speak, of the rotor with the help of heat.
volzhanin
Igor, there is such an idea… You don’t have a uniform magnetic field on your table, but if you make a spinning top out of several magnets, and spin the table… Maybe the spinning top will not lose momentum… What do you think?..
Anton Simovskikh
Igor Beletsky, have you figured out the physics of the process? Why is levitation possible only in dynamics? Do the foucault currents arising in the top affect the stabilization of the top?
The simplest installation with a levitating object on a magnet
To do this, you will need: a box of CDs, one or two disks, a lot of ring magnets and super glue. You can buy any magnet in the Chinese online store.
When your friends come to visit you, they will be surprised by the spectacular design that you created yourself.
How it works: In this circuit, an attractive force is generated between the electromagnet and permanent magnet. The equilibrium position is unstable, and therefore the system is used automatic control and management. The control sensor is a magnetically controlled position sensor based on the Hall effect MD1. It is located in the center of the end of the coil and is fixed. The coil is wound with varnished wire 0.35-04 mm, and has about 550 turns. LED HL1 shows with its glow that the circuit is working. Diode D1 ensures the speed of the coil.
The scheme works as follows. When turned on, current flows through the coil, which creates a magnetic field and attracts the magnet. In order for the magnet not to turn over, it is stabilized by attaching something to it from below. The magnet takes off and is attracted to the electromagnet, but when the magnet enters the range of the position sensor (MD1), it turns it off with its magnetic field. The sensor, in turn, sends a signal to the transistor, which turns off the electromagnet. The magnet falls. Leaving the sensor sensitivity zone, the electromagnet turns on again and the magnet is again attracted to the electromagnet. Thus, the system continuously oscillates around a certain point.
Scheme:
For assembly we need:
1) resistors 270Ω and 1kΩ (0.125W)
2) transistor IRF 740
3) LED
4) diode 1N4007
5) Hall sensor AH443
6) breadboard
7) varnished wire 0.35-0.4mm
+ housing, soldering iron, etc.
Scheme:
We collect the coil. The frame can be made using a thin sheet of fiberglass and an old felt-tip pen.
Cut out: (approximate coil size: height - 22mm, diameter - 27mm)
Gluing together:
We wind about 550 turns: (varnished wire 0.35-0.4mm, in bulk, but more or less we try to wind evenly)
Soldering the control board: (I used a regular 3.5 mm miniJack as a power connector)
Pinout:
For ease of assembly, you can use pin connectors:
We cut out all the necessary holes in the case:
Putting everything in place:
Now you need to make a mount for the coil:
We fasten to the body and fasten the coil:
This is how you need to bend the Hall sensor, solder the wires to it:
We connect everything to the heap:
After we get the magnet, you need to determine which side to orient it to the electromagnet. To do this, we place and temporarily fix the Hall sensor at the very bottom of the coil. We turn on the Levitron (the LED should light up) and bring the magnet. If it is attracted to the coil, then the magnet is oriented correctly, but if the magnetic field of the coil pushes it out, then the magnet must be turned over. Attach something light to the bottom of the magnet. In my case, it's an LED.
