Introduction: Electromagnetic Fidget Spinner Accelerator

Picture of Electromagnetic Fidget Spinner Accelerator

Fidget Spinners are little plastic toys with a bearing in the center. They are fun for a little bit, but get boring after a while due to their slow spinning speeds. There are ways to make them spin faster, but these methods involve using a bulky air compressor or an expensive can of compressed air. Luckily, I have found a cheap way to accelerate these fidget spinners to extremely high speeds with the power of electromagnetism. You can even hold the spinner in your hand while you accelerate it! I have clocked a spinner that is spinning with this accelerator at speeds up to 1440 RPM, that is fast. You can build this accelerator too, it is really cheap and really simple to build.

The video below compliments this instructable and shows this awesome Electromagnetic Fidget Spinner Accelerator (EFSA) in action!

Lets Get Started.

Step 1: How It Works

Picture of How It Works

This fidget spinner accelerator works by using an electromagnet with a reed switch and a fidget spinner with magnets mounted on the 3 sides. First of all, the magnets on the fidget spinner are mounted so that all the magnets have their north pole facing outwards. The electromagnet is wired so that the side that is closest to the spinner will have a north polarity when it is powered. When the spinner starts spinning (Refer to the above diagram) the electromagnet will be off. As the magnet on one side of the spinner passes the electromagnet, it will trigger the reed switch, activating the electromagnet. Because both magnet and electromagnet will now have the same poles, that arm of the spinner will be pushed away from the electromagnet. When it moves far enough away, the reed switch will disengage and shut off the electromagnet. Because the spinner will be spinning from this first cycle, it will have enough momentum for the next arm to move past the electromagnet and reed switch and repeat the cycle. As each arm moves by the electromagnet and get repulsed, the spinner will speed up and gain momentum. That is how this system of acceleration works!

Now, for how the circuit works. The reed switch alone cannot handle the high currents that the electromagnet draws, so it will need a buffer between it and the electromagnet. This buffer will be a MOSFET transistor. When the reed switch is triggered, it will let current flow from VCC to the gate of the MOSFET. This will allow current to flow form VCC, though the electromagnet, into the drain of the FET, and out of the source back to ground. The diode on the electromagnet is called a flyback diode, and its purpose is to absorb all the excess energy created by the collapsing magnetic field of the the electromagnet. Without it, the MOSFET would potentially be fried. The resistor from the gate of the MOSFET to ground serves to drain the excess charge from the gate after the reed switch turns off. Because the gate of the FET has capacitance to the source, this means that even after you remove power form the gate, the MOSFET will still be on, causing the circuit to constantly be on. The resistor prevents this.

Step 2: Materials

Picture of Materials

For this project, you will not need very many materials. You will need:

  • A 3 arm Fidget Spinner(Well Duh)
  • Small Ceramic Magnets
  • A piece of perf-board
  • An N Channel MOSFET(Almost any one will work)
  • A magnetic Reed Switch
  • A 10k resistor
  • An inductor (More information in step 5)
  • A 1n4004 diode
  • Wire
  • Terminal connectors
  • 12 Volt Power Source (Batter or bench power supply)

Step 3: Tools

Picture of Tools

For this project, the tools you will need are:

  • Hot Glue Gun
  • Soldering Iron
  • Wire strippers/cutters
  • Hacksaw


  • Oscilloscope

Step 4: Setting Up the Spinner

Picture of Setting Up the Spinner

To set up the spinner, you will just need to take three magnets, and hot glue them to the three arms of the spinner. Now, when you attach the magnets, make sure that the same side, or pole, of each magnet is facing out. This means that after you are done gluing them in place, you should be able to take another magnet, and hold it to all the magnets with the same side, and get the same reaction. In my case, there was an indentation on the north pole of the magnet, so all the indentations faced outwards.

You will also need to make sure that you use the same amount of hot glue for each side. If you do not, then your spinner will be unbalanced. It is also important to use a lot of glue, if you don't, then a magnet might fly off due to centrifugal force, also known as tangential velocity. This might cause, I don't know, maybe a dent in the wall? (I know from experience. Haha). It will also cause your spinner to become unsafe. Now, it is time to start building your circuit!

Step 5: Choosing an Inductor

Picture of Choosing an Inductor

The inductor is one of the most important parts of this project, it acts as the electromagnet that makes the spinner spin. This means that you will have to find the perfect inductor. You can start by digging through your parts drawers of inductors. You will first need to find an inductor that has the perfect resistance, and is not magnetized. Some inductors are magnetized, and these will not work, so before using one, hold it up to a piece of metal. If it sticks, don't use it. You also need to find an inductor with the right resistance. To high of a resistance, and the feild will not be as strong. To low of a resistance, and it will draw too much power. My inductor came out of an old TV board. It is 2.9 ohms and 5.82mH. Make sure that the inductor you choose is made of a ferrous material.

To test your inductor, set you fidget spinner down, and connect the inductor to a power supply. Then, tap the power supply leads on and off the inductor pins while moving it near the spinner. It should cause the spinner to spin! You may have to go though some experimenting to find the right inductor for your project.

Step 6: Cutting the Perf-board

Picture of Cutting the Perf-board

The perf-board is what holds all the components of the EFSA. You will need to cut it so it is large enough to hold all the components for your accelerator, but not too big. You will also need to cut a triangle off of one end to hold the inductor. I made all the cuts in my perf-board with a hacksaw.

Step 7: Soldering the Circuit

Picture of Soldering the Circuit

This is one of the most difficult parts of this project. You will need to follow the circuit diagram to solder all the parts of the board in place. The positions of the reed switch and the inductor are very important. The reed switch needs to be far enough away from the inductor so that the magnetic field will not cause the circuit to self trigger, but close enough to make the circuit run as efficiently as possible. You will need to do a little experimentation to find this sweet spot. I used screw terminals to connect the inductor and the power wires to the board. You will need to make sure that all the connections shown on the circuit diagram are soldered on the perf-board in real life. Look at the pictures closely to find further know how to solder this board. When you are done soldering the accelerator board, then you should be ready to test it!!

Step 8: Power Supply

Picture of Power Supply

This fidget spinner accelerator needs a power supply that can provide 12 volts at 1.5 amps. This power draw will change based on the specs of the inductor you use as an electromagnet. If you just want to use this accelerator at your desk, then you can just connect it to a good bench power supply or computer power supply. If you want to make it portable, then you can use a LiPo or LIon battery. To find out how to make your own 11.1 volt LIon battery, check out my instructable and YouTube video below.

Step 9: Finding the RPM

Picture of Finding the RPM

To measure the RPM of this fidget spinner, all you need is the accelerator and an oscilloscope. First of all, you will need to connect the probe of the scope to the gate of the mosfet. This pin will be high 3 times per revolution because the magnets on each arm of the spinner will trigger reed switch each time they pass it. Then, ground the oscilloscope to the ground of the accelerator. Finally, get a friend to use the fidget spinner accelerator while you look at the oscilloscope. After the spinner was up to full speed, the scope registered a frequency of 72 Hz. This means that magnets were passing the reed switch 72 times per second! You can divide this number by three to find the rounds per second, which would be 24. You can then multiply the RPS by 60 to get the RPM: 1440. This fidget spinner accelerator really makes the spinner spin fast.

Step 10: Have Fun!

Picture of Have Fun!

To use your spinner with the accelerator, simply hold the spinner with one hand and the accelerator in the other, then give the spinner a little jump start. After that, hold the accelerator closer to the spinner without touching it, and you should see it start to accelerate! The closer you hold the accelerator, the faster it will go!

This device is really a lot of fun. It is especially cool to feel the gyroscopic effect of the spinner at these high speeds. You can also impress your friends by spinning your spinner faster than any of them can. The Electromagnetic Fidget Spinner Accelerator turns a regular old fidget spinner into a truly awesome toy.

Thanks for reading and good luck building! Also, remember to vote for me in the contests!


3967 (author)2017-08-31

hello, can you make it faster like 10000 or 20000 rpm ?

if not , why only 1440 rpm?

ReneJ2 (author)39672017-11-01

the "bad boy"

v=R(m)·dφ(rad)/dt(s) → dφ=2π=360° → dt=1/f → 1Hz=60rpm

the projectile speed (at glue failure) = v = 0.04(m)·2π(rad)·20k/60(Hz)=(apx.)84(m/s) = 300km/h = 187.4mph = 1/10 or 10% of the speed of the M6 bullet

charlessenf-gm (author)39672017-10-03

I would think the reed switch could effectively limit the speed as it is a mechanical device. If there is a solid state alternative available, it might allow for faster revolution.

As well, mounting the spinner and 'accelerator' so as to allow better control of proximity as well as a 'steady rest' might well allow for better performance.

LiamOSM (author)charlessenf-gm2017-10-17

A hall-effect sensor would be a big improvement over a reed switch. Once you overcame the limit of having a mechanical switch, it could theoretically accelerate until the air resistance (drag) equals the force applied by the electromagnet, causing a net force of zero and therefore no acceleration. That is, assuming there wasn't any other bottleneck component like the speed of the transistor.

RiccardoM36 (author)2017-10-27

Is there anyway to control the speed? For example between 500-1000 rpm?

TomP216 (author)2017-06-15

This is a fantastic project and I think it has the potential of educating my boys in a number of ways. My problem is that I don't have a "drawer of inductors". Can you recommend a model/part that I could find on Amazon or at Micro Center?

SameerH10 (author)TomP2162017-09-16

I have the same issue - all the inductors I tried were magnetic. Any luck finding a non-magnetic 5nH inductor?

stuffdone (author)2017-08-30

Hmmm how about the power of light? I have some 2 watt lasers that pack a punch ( goggle mandatory ) but perhaps photons can spin something for fun? I may try this.

zencuke (author)2017-08-29

Very clever. Thanks. I'll make one tonight. Of course you have just reinvented the electric motor.

Edgar (author)2017-08-29

Beware, this might set you off to build Bedini machines...

Here's an oooold book, older than even me, that you might like:

talk2bruce made it! (author)2017-08-06

This morning I put one of these together. Works great! Thanks for the terrific instructable.

talk2bruce made it! (author)2017-08-06

I made one of these this morning. Works great!

Maker Saga (author)2017-08-06

Not sure if my last nearly identical comment went through (bad WiFi connection and browser keeps crashing) but I meant to say this is way cool!

Maker Saga (author)2017-08-06

This is super cool. Congrats!

JeffP160 (author)2017-07-11

This is fantastic. It was exactly what I was looking for to impress my grand kids. Is anyone interested to build it for me for $$, as I don't have the expertise to find all the components to build it. Or can you tell me where to buy the components?

ajacks504 (author)2017-06-29

Great job!

I'd love to see what would happen if you swapped the reed for a Hall effect switch. Maybe the mechanical actuation time is what's limiting it so far. 120hz+ seems like asking a lot of the poor reed switch.

Would be neat to actuate it with a micro and PID loop, maybe even display the RPMs and control with a pot/buttons!

Chaitran77 (author)2017-06-24

I made it!!!!!! Thx a lot

Quantumdust (author)2017-06-13

Great project! Love your lab. Based on the photos and video, you really seem to be talented and know what you're doing (rare). Reminds me of my setup about 50 years ago when I started designing projects. All with vacuum tubes, and I was happy as a bunny when the first transistor was actually available for buying.

One small comment re one of your descriptions (think about it and the physics will make perfect sense):

You say when talking about gluing the magnets "then a magnet might fly off due to centrifugal force, also known as tangential velocity". What really happens if the glue lets go is the magnet flies off " in the direction of the instantaneous tangential velocity". The glue exerts a centripetal force on the magnet keeping it locked going toward the centre of the spinning system. Centrifugal force is a fictitious never-ending historical misunderstanding. If the glue breaks the magnet travels, as you say correctly, tangentially. If centrifugal was real, the magnet would fly in a radial direction outward. Never happens, try it!

EdM42 (author)Quantumdust2017-06-13

Well, not really. It depends on your frame of reference. If you are standing still outside the rotating body, there is no centrifugal force, it's just radial acceleration and the weight will fly off tangentially.

However if you are standing inside the rotating body, your frame of reference is rotating with the body and centrifugal force is real. As a matter of fact, if you release a weight, it will fall down towards your feet not tangentially because your frame of reference is moving. (for short distances only because your frame of reference is curving but the weight is moving in a straight line - coriolis effect - that's what causes hurricanes and tornadoes)

Quantumdust (author)EdM422017-06-13

You're mixing a lot of things together that tends to make the basic idea fuzzy. Ignore gravity, falling on your toes (ouch) and hurricanes. Frames of reference do not change the basic concept and physics of the system. Centripetal implies seeking the central point of the motion and centrifugal says the object is trying to get away from the centre. An analysis of any rotating system, be it a ball on a string or an orbiting planet held by gravity, will show a force vector that is always pointed toward the centre of motion. It feels like the ball is pulling on the string and wants to get away from the centre but in reality it's the string that is pulling on the ball to keep it rotating since it really wants to keep going straight (tangentially). The string pulling on the ball or gravity pulling on the planet are the only forces involved in the math.

Remember the old " every action has an equal and opposite reaction" ?Centrifugal is a name for an opposite reaction to the real centripetal action the keeps the object moving in a nice circle around whatever the centre is. Cut the string, the reaction disappears and the object keeps moving in a straight line. Sorry for the long-winded story.

EdM42 (author)Quantumdust2017-06-14

Ok, fuzzy and off topic, but while a moving frame of reference does not change the physics, it does change the math needed to represent the physics. It also changes the apparent motion you think you see if you are inside the moving frame of reference.

Coriolis force/effect is an explanation for why something does not move in apparently straight lines inside your moving frame of reference.

Centrifugal force is not fictitious, it is merely a description of apparent forces inside a moving frame of reference. (and besides, nobody can define the non-moving center of the universe, so all frames of reference are moving - you just pick one that makes your math easiest)

Quantumdust (author)EdM422017-06-14

Hey Ed, I'm not trying to be a pain, it's just that after 40+ years in sensor R&D I've developed a few items (I call them my "sweet spots") that will bug me forever.

You seem to be one of these very rare people these days that actually understand the math and physics behind what they think they know about. Using today's newest buzzword, " having said that" , the answer to the discussion is that we're both right. The rotational reference frame is the key to the whole thing. Centrifugal is only both fictitious and a reaction force in an inertial frame. Putting yourself in a rotating frame makes the math easier and generates the need for existence of the otherwise fictitious forces to make the analysis work.

This silly discussion has been turned over and over a million times over the last thousand years by people way smarter than both of us and, depending on what "FRAME-of-mind" you are in, the discussion will persist ad-infinitum.

If you need both a good night's sleep or stay awake forever :-) , read the text in the Wikipedia link here:


Cyberchipz (author)Quantumdust2017-06-20

You guys are funny! I'd say we apply a light touch of Occam's razor, and just for the kids, apply a little physics KISS! :-) At 1440rpm, I'm sure the kid's frame of reference is a bit 'fuzzy'. lol I think just saying it moves in a straight line tangentially is a pretty good observational 'consideration' because proving it would be a tough call. But, after it hit the wall, drawing a mental straight line from the dent to the circle traced by the fidget magnets would not prove it, but be a keen observation and application some rudimentary concepts. But, I do thank you two for the chuckle! lol

Quantumdust (author)Cyberchipz2017-06-20

I'm very 'fuzzy' about the point and subject of your memorable text.......

Cyberchipz (author)Quantumdust2017-06-24

BTW, as a Metrologist, I wanted to say, since you're a sensor guy, my favorite sensor is the LVDT. I used it, and some other equipment when I worked for NASA to develop a analytical computer app in comparative dimensional measurements utilizing lorenz attractors to increase our accuracy and precision by a factor of 10, giving us the best effort result in a national measurement assurance program (MAP) comparison of one of NISTs primary dimensional standards to < 0.5 sigma in a 1:1 comparison. Yea NASA! XD The rest of the country was between 1 and 1.5 sigma! Typical. This was around 20 years ago, I have no idea what they can do nowadays. Perhaps I introduced a new analytical method?! The lab was stable enough to have only two attractors, the smaller, denser one became the sampling position. Sorry, but I digress.

Cyberchipz (author)Quantumdust2017-06-24

Perhaps I should clarify, for others, but I think you get the point. The only clarification I would make is my own modification of KISS, which is Keep It Simple Savant! Something I must remind myself to do often. By that I mean I followed both of your discussions, and Gee willikers! Give the kid time to grow into it. lol XD

Cyberchipz (author)2017-06-20

Well done! I admire your enthusiasm! I voted for you on both the Invention Challenge, and Explore Science contest, well qualified for both!

RocketPenguin (author)2017-06-16

I do realize that it wouldn't spin forever, but wouldn't it spin longer?

RocketPenguin (author)2017-06-13

Here's an idea: make the center "bearing" a brushless motor, and have it act as a generator, as well as a motor. The initial spin would charge a few capacitors, and when it would slow down, the current flow would reverse, turning the "generator" into a motor. The system would switch back and forth until it stopped moving (due to friction/obviously isn't perpetual motion).

It would actually spin less. Same amount of energy input, but some is used to charge the capacitors so less spin.

I'm guessing magnetic friction?

Conservation of Energy. Magnetic friction is the same is both cases.

JeffB7 (author)2017-06-13

I would consider a different timing method that does not rely on attaching anything to the spinner. Or if I absolutely had to, I would use something with a smaller rest mass. Maybe a small mirror and use an IR LED and IR sensor for timing.

If you build it with magnets, at least wear safety goggles when using it. As best I can figure it, if your fidget spinner has a diameter of 3" then 1 magnet travels that circumference each revolution or 9.42 inches. At 24 revolutions per second, each magnet is traveling at 18.84 feet per second. If a magnet lets go, it will travel over 3 feet in .2 seconds. More than fast enough to cause ocular damage.

wquoyle (author)JeffB72017-06-14

The magnets are essential to the functionality here, without them nothing will be spinning. They're not there just for measuring the timing but an integral part of the 'motor'.

bricomario (author)2017-06-14

Very nice project ! I'm interested about the tool (DIY I thing) measuring the uHenry and the ohm value (small green screen). If you can post the circuit to buil it, it would be very appreciate !

Vladlog (author)2017-06-13

Very nice! Great idea!

HansG30 (author)2017-06-13

Nice work

duracsea (author)2017-06-13

A sweet little toy. It has potential as with the Bedini Schoolgirl Motor circuit. Try adding a bifilar coil around that six microhenry choke [with an appropriate NPN BJT] wired in and use the back-emf across the choke to charge those batteries. This thing you came up with is actually an attraction motor and when scaled up properly it can take a house off the grid. The house runs on inverters across two sets of batteries, one set of batteries is being charged while the other is powering the house; when power is nor being used it can be sold to the local power company.

bpark1000 (author)2017-06-13

Various schemes are proposed for sensing the magnetic field (reed switch, hall sensor), but the simplest one has not been mentioned: induction in a coil when the field changes. Look up this toy:

The original versions of this toy have a nail with a center-tapped coil wound on it, mounted vertically under the center of the base. Also there is an NPN transistor (2N3904) and a 9 volt transistor battery. one section of the coil is in series with the transistor's collector, and that is across the battery. The other coil is across the emitter-base of the transistor. The coils are phased so when the transistor turns on, the mutual induction to the E-B coil turns the transistor on further. In the presence of the initially spinning top, brief current pulses to the coil keep the top spinning (for about 2 weeks on a 9V battery).

This same circuit could be used for the spinner accelerator. The drive coil would want to have fewer turns of heavier wire, as there is more friction on the spinner versus the top. This patent on the top explains the circuit in more detail.

The advantages of this scheme are that no on/off switch is needed (the circuit automatically shuts down when the spinner is removed), an absolute minimum of parts are needed, and these are inexpensive.

MakerStudioNZ (author)2017-06-13

Nice project, I will take a try

fabriciowebber (author)2017-06-13

Maybe adding some cable ties would add more safety to the magnets? I wouldn't trust hot glue for "high stress" applications.

TechPaul (author)fabriciowebber2017-06-13

Magnets that could be screwed on, center hole, might be better

fabriciowebber (author)TechPaul2017-06-13

Even better. It would be a bit hard to balance the spinner, but it would be even safer.

davebodnar (author)2017-06-13

GeraldoG6 - FYI, I posted a similar Instructable last week that has options for a physical switch, reed switch, Hall sensor and phototransistor sensor - have a look here:


GeraldoG6 (author)2017-06-13

You can get higher speed using a a Hall transitor instead of reed-switch.

Steinzel (author)GeraldoG62017-06-13

I was going to mention this also, the reed switch is limited by the speed at which the reed can move. Hall Effect is not limited by this.

Lennerton (author)2017-06-13

Love the enthusiasm. Great project.

DougM95 (author)2017-06-13

Great idea and GREAT explanation of how the circuit works.

One word for future videos. Try to get out of the habit of using the word "now". Watch your video again and see how many times you use it. It will hep you in your adult life not to use it so much.

Thanks again.

rubendlove. (author)2017-06-13

it's like the bedini project. the same principle.

Saeed Nazarian (author)2017-06-12


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