HACKED!: Using an HDD Motor as a Rotary Encoder?!

[@aggeloskoumaniotis]

You are doing an awesome job , the videos are very informative , beginner friendly and you also answer most of the questions in the comments . The ads on your videos are short and not promoting useless stuff . Thanks for being such a nice creator .

[@greatscottlab]

Thanks for the feedback

[@leemathoo6583]

I don't mind the adds as long as the content is good and the adds are short and relavent to the content....

[@alexopouloscharalambos8242]

Great idea ! I think you can improve it a little. You can only use L1 and L2 to determine the direction of rotation. At Low to High transition of L1 check the state of L2, if it is High the it turns clockwise else it turn anticlockwise (or vice versa).

[@mahershhab3824]

ممكن مساعده بمقابل مادي

[@Enigma758]

There is some potential latency when you do it that way.

[@jakeguard9099]

"simple schematics"

[@konceptochannel]

yeah, I thought the same thing... " *yeah, sure.... pretty simple* "

[@nuthinnew]

koncepto I totally know what you mean. But a few weeks ago I downloaded an app called icircuit for a work project. I’ve only made basic circuits with motors and lights before now so had no hope I could use it. I googled how to reverse polarity (for the project) and it showed me a circuit like GreatScott’s so I copied it to the software and made a mock up circuit for my project. Then I looked on ebay for the components in the diagram and they are just 8 pin chips and a few resistors. I’ve learned in the last few weeks it looks much scarier on a schematic to what the product in your hand will be

[@nuthinnew]

@michel777ification How many times has it got you laid? Loads i'm guessing

[@elshujau]

I thought the same

[@elshujau]

Now you have made a turntable. Let's DJ

[@alfonssiggler6652]

Thanks for another year full of awesome projects! Cant wait for the upcoming episodes of 2018 :)

[@greatscottlab]

Thanks for the feedback. I will give it my best in 2018 as well.

[@luongmaihunggia]

You mean 12018?

[@sagarkapasi099]

+redstone craft guy i saw what you did there

[@ECrackers]

Yeah , i also.

[@nThanksForAllTheFish]

Hope you hit 1M subs in 2018.

[@KerryWongBlog]

Great video as usual. You could use the analog voltage generated to determine how fast the motor is spinning and thus make it a velocity controlled rotary encoder so that the faster you spin the more you change the output number.

[@robmarrin6720]

Man I did electronics 27 years ago usind avos and old oscilloscope, in college but this is amazing stuff.. You have rekindled my love of electronics, and computers I used to build my own pc towers... Great information totally within the ability of novices having watched you tutorial, can't thank you enough. Rob👍👍👍

[@inverted311]

Seems to be exactly how modern graphics engines work... Could be useful to try and battle online network clans.

[@suryanshthakur5820]

One like for the motor sacrificed.

[@hafizuddinmohdlowhim8426]

Not everyone in this world is generous enough to share this knowledge. Pay attention how he makes assumption and verifies it. He can do it because he understands the concept so well.

[@dave_dennis]

I’m an Electrical Engineer and yet I learn something on every one of these. Plus I love his pronunciation of hysteresis.

[@sorin.n]

Hi Scott, cool projects (as always); I was thinking that this could be taken to the next level where the rotation speed and acceleration would increment/decrement the value faster. Also, maybe keeping it connected to the analog inputs would allow to measure the amplitude, which is proportional to the speed. Great work! Stay cretive & I'll see you next time!

[@jothain]

Indeed. If I would have the needed skill, I'd try to implement this for my DIY small arcade cabinet. That HDD motor would surely indeed have very satisfying feel cause if it's good bearings.

[@user-xf9ny8qf3s]

Indeed. It's a hall effect rotary encoder.

[@Enigma758]

@@user-xf9ny8qf3s There are no hall effect sensors in his hard drive motor. He relies on measuring the voltage resulting from induction while spinning the it. In effect it is acting as a 3 phase generator. What you are referring to would be a sensored BLDC motor. You can make a much better encoder from a CD rom drive spindle motor that is sensored (has hall effect sensors). That is a totally different principal than what he is showing here. Instead of tapping into the coils, you would tap into the hall sensors directly.

[@user-xf9ny8qf3s]

@@Enigma758 I mean that's how hall effect sensor works.

[@Enigma758]

@@user-xf9ny8qf3s I mean that in the video, it is imprecise due to the fact that induction depends on motor speed. Many who have tried it complain about that and they are correct. Using hall effect sensors in a sensored motor totally avoids that problem.

[@zanpekosak2383]

Making a dj turntable from this might be good...🤔

[@calebevans9562]

I am about to try this

[@stand1rte]

you can use the midi keyboard project of evan kale, and simple add this to control some programs

[@DJDiskmachine]

Would be awesome, but it seems like the platter needs quite a lot of rotation for the value to change. =/

[@moiquiregardevideo]

We can increase the resolution by a factor of 3 by using interrupt on each of the 3 inputs. The global position counter is incremented/decremented by each interrupt.

[@raymondmichael4987]

What's hell, thumbs down!!!!!!!? This channel give us soo much great content how come someone rate it down; the guy put a lot of effort to make this understandable, at least appreciate the effort of the man. Great content as always

[@EmmanuelAyegba]

KZbin is full of psycho trolls who will thumb down even without watching.

[@leemathoo6583]

Don't bother about them they never understand anything in this video and never will.....

[@elevatormaniacgames]

Don’t bother less than 1 percent disliked

[@xxportalxx.]

Personally I am slightly dissatisfied by the fact he uses the motor, not the actual harddrive hardware as the encoder.

[@88njtrigg88]

The software people, who actually thought it was a software hack.

[@Ricky_B4]

This has got to be one of the best videos I have seen. It is clear, concise, and informative. I have disassembled hard drives for parts, also to ensure the information on the platters is destroyed but to use the motor as an encoder didn't cross my mind. Thank you for sharing.

[@jaredcohen9552]

I have two questions about this project: 1) why is using the analog read not good? 2) is there a way to speed up the counting? When you spun it fast the numbers went up slowely

[@glenn0010]

1) Typically you want to use analogue to digital converters for something else like sensors since a micro controller usually has only a few of them

[@greatscottlab]

1) Because your Arduino might not measure the the phases at the right time because it is currently doing something else in the code. That is why interrupts are so important. 2) Yes, you can enhance the code quite a bit and add more functions like counting up according to the rotation speed.

[@jaredcohen9552]

Aah that makes a lot of sense! Thanks for clearing it up, keep up the great content

[@z4nadeesh]

Analog to digital converters are generally slow and takes up more processor time. ISR and digital comparisons usually take lot less CPU time. ( Edit: Also you could use the ADC for something else instead of wasting it on a rotary encoder) And I think it can be sped up by tweaking the code

[@Fawks]

1) I guess using the adc is less effective than just reading a digital value 2) decrease the delay (7:48)

[@bobbysenterprises3220]

Thanks. From a brush less quadcopter & drone enthusiast that recently learned about rotors encoders while trying to build a PID gas burner control for my work. I may try this in the future. Good work with your videos informative and enjoyable

[@GearDownForWhat]

For quite a while I’ve thought about starting a website that would work like a hackers search engine, you type in rotary encoder, and it spits out an everyday object where you can get one, in this example, a hard drive. same with the magnets.

[@MarkyBhoy-fe1xf]

good idea!

[@commentsonyoutube645]

Hi, Only 2 outputs from compactor can be used, same way as in rotary encoder. On every interrupt just check state of one phase, and you have instant direction. Also you can start timer in INT, and read it in another, so you have rotation speed, without using processor. And finally use third coil to add force feed back to user. Also is possible to use multiple coils to provide sound, vibration, steps, lock, etc... I think that this could be very interesting, and relatively simple to implement in hardware. Thank you for your videos, and keep up with good work.

[@Enigma758]

I think there's more to it than just checking the state of a single phase.

[@bananobanana1870]

what is the minimum velocity you'd need to turn it, so that it works? I guess it is a lot higher than with the incremental rotary encoder?

[@3deeguy]

I'm going to refer back to this video for my sensorless bldc motor experiments. I tried to breadboard a circuit a couple of years ago but I could only make the bldc spin like a stepper motor. It would only run smoothly after it reached a certain speed. It had no useful torque because I did not know how to set up the comparators. I'm not going to hack a hdd motor but the information in this video is absolutely useful. Thank you!

[@harviecz]

Can you make it spin by itself at low-torque while still remaining the ability to work as encoder? That would make nice DJ controller, since most controllers do not spin by themselves as vinyl deck does.

[@hanelyp1]

The control system would be a lot more complicated, but brushless DC motor drivers do something like that to monitor the rotation of the motor as it's driven. While power is applied between 2 phases on the motor, the 3rd is watched to observe rotation.

[@3v068]

Dear Scott. During my journey into learning electronics, I've used your videos a lot and I have learned a lot. This video might make me actually start my Disc Jockey from scratch idea. The encoder is exactly what im looking for to make one for my DJ setup and its been a rather dumb little goal of mine to build a working one. Something similar to a CDJ-2000 from Pioneer, just cheap and not at all packed with features lol.

[@PolakPL2002]

Is it possible to increase sensitivity of the encoder?

[@greatscottlab]

+GreenMC If you put more time into the code you can even let the Arduino react according to the speed of rotation. So, yes.

[@Thomas_Ricks_]

hey, your first again!

[@djmips]

Trust me, this is going to be mentioned a few more times in the comments... :/

[@Skelpolu]

would it be possible to see a video on that? Specifically, it'd be awesome to see the motor inside a case, maybe even with a small 3d-printed knob.

[@killymxi]

Yep. Sensitivity to small input is what actually will make it interesting.

[@markschmidtinsydney]

Mate, KZbin is full of clever people coming up with clever ideas, based on previous clever ideas. Yours is magnificent. And really well explained too.

[@ScientificSolutions]

Very clever application, thank you for the wonderfully detailed explanation (as always). Shouldn't it be possible to use only two of the motor phases? Instead of being ~90 degrees phase shifted (as in standard quadrature type rotary encoders) the two outputs would be ~120 degree phase shifted.

[@mashfaqm]

yup, im pretty sure we can. Since most incremental rotary encoders actually use 2 signals only.

[@Enigma758]

@@mashfaqm But then there is latency since only a bit changes across the 3 phases at a time.

[@taister211]

Stumbled on this video trying to find out how to wire a hd motor, Man I wish i knew what you were talking about in the most sincere form, Should have gone to college and studied electrical/mechanical engineering. Thanks for what you do at the very least.Cheers

[@jmkdev]

GreatScott: *makes super easy to understand circuit and code* Me: Wow! That’s sup- GreatScott: EXTERNAL INTERRUPTS

[@ginonigro9730]

I was looking for a way to make a rotary encoder from a HDD motor but found your instruction very interesting and easy to understand. Thanks and keep em coming.

[@FJB2024_]

You're my favorite creator. I can't wait to see what's coming up next. Almost always a learning experience. ESPECIALLY when you do mosfets and IGBT ;) I don't think we get enough examples of arduino and pi "real world interfaces". how about some home appliance hacking with an esp8266 and mqtt ?

[@dylancruz1131]

Look at KanKun wifi smart plugs! They come loaded with BusyBox linux with an SSH terminal open! you can hack them and make them do whatever! really fun!

[@kurtnelle]

I've found a paper that says, if you energize one of the phases of a stepper motor, you can also make it a rotary encoder. Except that it will create noticeable, desirable detents when the user is moving it.

[@Candy-uo8sv]

Make it so if you spin it faster it changes faster

[@ruenahcmohr]

For a hand operated encoder, I found that what worked really nicely, was taking a dc motor, hooking each side to an adc channel, centering one side at 2.5V, doing a diff of the values of the two channels, and integrating the value for position. There was a LOT less drift than I thought there would be, its easy, give it a shot! I did it for my new CNC pendant. ... which apparently.... I didn't do a build log of.... }:-/ ... and I didn't post on thingiverse.... }:-/ ok, hmm, if anyone cares or is interested, give me a shout.

[@locha9827]

So you just made electric fidget spinner

[@nightmareinaction629]

Lexa9966 fuck no its not a fidget spinner

[@ppprdr4666]

how to delte others posts

[@samsawesomeminecraft]

flag as spam/inappropriate

[@TR2000LT]

@@samsawesomeminecraft OKAY I'D SAY IT'S VERY INAPPROPRIATE! LET ME FLAG..

[@devhassanmehdi]

Am i the only one here who dont understand a single thing but still loves to watch Scott's projects? aha

[@wiredsotu19]

Man I'm so much big fan of urs... I really like all video🔥🔥🔥

[@greatscottlab]

Thank you :-)

[@GadgetReviewVideos]

Take the platters and hang them at different lengths from some string, they make neat wind chimes, nice sound, and the reflections from the sun create nice color reflections.

[@233kosta]

This is probably better used as a rotational speed sensor

[@cedricpod]

especially as the signal levels rise as the speed rises

[@robbielerenne594]

Great idea but I don't know if there is a law between the output voltage of the motor and the speed, and if it is Linear

[@233kosta]

@@robbielerenne594 That's irrelevant. All you need is a Schmitt trigger and a quiet signal path to it (a wee bit of coax will do it). On the other side you're counting pulses just like a normal encoder. Your arduino will quite happily play frequency counter (or more likely - frequency timer) and tell you how fast you're turning it as long as there's enough signal to set off the Schmitt trigger (so maybe not 0.02 rpm :P). Connect two windings to the arduino (separate inputs) and you can also tell which way it's going.

[@233kosta]

@@robbielerenne594 Also, yes there is and no, it's not. What you've got there is essentially a fairly inefficient (compared to purpose-built units) three phase permanent magnet synchronous generator. Y'ain't gettin' power out of 'er, but you'll get enough AC on the other end to run some high impedance logic (see last comment). You also want to make sure the arduino itself is well protected from the motor. These are sizeable inductors near some skookum magnets and unless you're willing to splash on a good scope and spend a few evenings testing the thing to death I would NOT count on that signal being too weak to damage your inputs. Send it into something high impedance, make sure it's not something that will short its input to its output lines when it fails, and count the pulses ;) Also, do NOT connect a 2.2mF electrolytic cap to the 5V regulated output of your arduino with no current limiting :D

[@D0t0ne]

I have no idea what this guy talks about 99% of the time but still I watch his videos religiously to the very end. Ready to bet I am not the only one, or am I!

[@xxmountaindewxx7893]

How is your English so good? Mine is under all pig.

[@greatscottlab]

Haha, I would not say that my English is that good but you learn a lot after 4 years of producing english videos.

[@pauhull]

lmao

[@AtticusDraco]

mind blown never ever considered that hack patiently waiting for a HDD to go bad now

[@hotfreshrider]

I've always wondered this, would love to see some Arduino code to turn it into a HID master volume control.

[@Gameplayer55055]

You can use digispark, or standart Arduino with serial, but with soft on pc

[@LyneisFilm]

Brilliant. I took one of these motors apart, but missed the fact that the outer ring which rotates has multipole permanent magnet, which then easily driven by the internal coils.

[@razvan6936]

A video about a volume control with rotary encoder would be great!

[@hafizuddinmohdlowhim8426]

razvan_wasd you don't need to use encoder to do volume control. Encoder is used to measure quantitive measurements like distance, RPM

[@maxximumb]

That could make a cool input for so many projects. Finally a use for the dozens of old HDD parts I've collected.

[@spicymemeboi2646]

That's one useful fidget spinner...

[@cessposter]

Not so Spicy Meme, Boi.

[@klazzera]

hello, i've done a similiar project in the past, but instead of using each period of the sine wave as a one step, i calculated the angle of the rotor continuously with practically infinite resolution only limited by the resolution of the ADC. the three phase voltage values are actually x-y-z coordinates on a tilted circle in 3d space. the normal vector of the circle was (1,1,1) as far as i remember, and doing some simple trigonometry, you can calculate the exact angle of the rotor as long as it's rotating fast enough to generate a measurable voltage. you can calculate the speed from the angle itself, however, the radius of the circle is also the speed itself.

[@BrunoPOWEEER]

Ohhh I have a collection of motors here (all sizes and power levels) thaaanks for the inspiration... rotary encoder POWEEEEEERRR hahaaa =]

[@ErickMirandadotcom]

POWEEERRRR!! bahAHHahHa

[@ManofCulture]

Heeeyy!!!!!

[@supersaiyangoku3580]

I also have motors mostly brushed

[@bergamt]

You can do the same thing with a stepper motor and get multiple ticks per rotation. It can be really useful if you run out of rotary encoders and have a spare motor.

[@hawkgaming8773]

Scot the DJ

[@Taran72]

Glad to be one of your many Patreaon supporters! Great video and great topic. I also learned about another source of three phase power for some of my projects. thanks again: I will definitely do this project.

[@videolabguy]

Great video! However... You only need two of the phases. Typical encoders operate in quadrature or 90 degrees. Yours operates in tritrature? or 3 phase. Wasteful. Also, no detectable output at very slow rotation. On a normal encoder, connect both outputs to an XOR gate and you double the pulses per rotation. Connect phase one to the clock pin of a 74HC74 D flip flop and the phase 2 to the D input. Now the Q output will indicate direction and the XOR gate output gives you finer resolution steps. This little bit of hardware "preprocessing" will free up the highly precious processing time in your microcontroller. For actual useful purposes, never process hardware pulses in software. A processor using 98% of its processing time to read a switch is just plain wasteful.

[@davethesatellite7319]

Why this only popped up on my feed today will be a mystery lost to the ages, however, its run in is impeccable, ill be using this in a super budget project within six weeks!!! Thanks @GreatScott

[@floriang7435]

Evan Kale did this with an Dvd Drive Motor. Pretty cool Check out his Channel

[@snchit4575]

Was about to search how to use hard drive motors and stumbled on this one.. You really are the best greatscott

[@ReevansElectro]

It is funny how you say that you will see us next time that we don’t ever see you and you never see us.

[@tyronenelson9124]

The rotary encoder dials you find in digital stereo equipment with only 3 pins work differently to that one, the cpu in the stereo just registers the order in which the pins get connected together to determine the rotation of the dial to either increase or decrease the volume, thats what i think anyway

[@chraso]

ur amazing electrical engineer. do u teach?

[@michael-rommel]

Jetzt weiss ich endlich, warum ich all die alten Festplatten aufgehoben hab... Super Video mal wieder!!! THX!

[@filipbitzan5208]

One question. Why did you upload a video on Saturday instead of the usual Sunday?

[@greatscottlab]

Because I and probably other people as well have other things to do on the 31.12.

[@cerealtech4138]

GreatScott! Would you consider to add an indipendent monitor to your cheap usb microscope using a raspberry pi (maybe the zero version).. sorry for the OT

[@tommihommi1]

GreatScott! didn't you build a firing system for fireworks some time ago? Have fun!

[@gertvarva]

my other thing to do is to get shitfaced and cry about my life on a hill i know til newyear comes

[@cerealtech4138]

MCA sounds funny

[@weazeldark3983]

With those small lcd 3 digit as counter and make a circuit board display replacement for the hdd plater u have a high end knob setup ready for all projects

[@deadchords4919]

you help me continoue my electronics thanks!

[@pierreretief]

Another excellent, Excellent, EXCELLENT video. I have been watching your videos for a while and the are great! Your ability to take mammoth amounts of information and condense it into a few sentences is incredible. The questions you ask (and subsequently answer) are all the right questions. It reminds me of the awesome old Mythbusters episodes. Can't wait to see what you bring us in 2018!!!

[@humongouschungus1856]

Anyone watching in 2019?

[@rjinnh3933]

As usual, great content and great presentation from Great Scott, who is always GREAT! A fun project would be to add some audio FeedBack for each 'tick' as when a key is tapped on a smart phone and then add a little 'KICK' with reverse voltage back into the phases to produce tactile FeedBack. Again, GREAT vid. Russ in NH

[@joveaaron-real]

Hi, this could be made using a Taptic Engine from an iPhone/iPad.

[@KrisX7331]

Can you explain how three phase electricity works.Im talking about mains electricity.

[@greatscottlab]

I put it on my to do list

[@FJB2024_]

yeah, especially how watts are measured across three phases! - maybe even a BLDC 2 phase to 2 phase converter !

[@lezenfilms]

GreatScott! Specifically knowing how many generators started at different times and places can all be in phase supplying mains power

[@FJB2024_]

they will auto sync.

[@KrisX7331]

Ariel Lezen I think its one generator just with 3 coils like 3 phase motor. I could be wrong tho

[@CharlesVanNoland]

I have a bunch of different encoders, some of them are the small clicky types like you have but I have ones that are completely smooth too in the same form factor and larger ones too - they are optical encoders.

[@rtarade1]

Can you program Arduino wirelessly ?

[@greatscottlab]

I think so

[@rtarade1]

Can you add this to your "To Do list"?

[@greatscottlab]

I am not interested in that. Google it. I bet there are plenty of tutorials about this out there.

[@Patrik2166]

You can do that over WiFi, BT or even with radio signals. It's all about creativity

[@philliptoone]

Rajat Tarade I would REALLY like to know how to do this. I've looked into it (Google) but haven't figured it out. If anyone can point me I the right direction I would be VERY appreciative. Specifically I would like to be able to program an arduino from an Android device over Bluetooth.

[@simtubes]

It's possible to get an instantaneous position by magnetizing the coils with a short pulses. For example, using your ESC, pulse each coil combination with a short pulse (just to avoid much heating) and note the comparator outputs on the 'scope. By measuring the decay times, you can actually translate the position accurately. It might also be cool to make some sort of enhanced magnetic detent / user feedback this way as well. This probably wouldn't work very well for something that has to not take too much power, though, without some sort of sleep state.

[@kkuhn]

wotawy encowdas

[@CoffeeDrunken]

“Modor”

[@ntnsonwale4381]

Great Scott you are really creative !!!! I think you are best on KZbin for electronics with creativity !!

[@greatscottlab]

Thank you very much

[@aneesh2033]

Sunday?

[@greatscottlab]

Next week!

[@pietervanniekerk4453]

I use JLPCB for my business .... the quality of PCB's they manufacture superb , delivery excellent ! Highly recommend

[@necoisidois7570]

Tabi pek sağlıklı bir encoder değil, Dönüş hızına ve süresine göre etki derecesi değişmekte. Çok yavaş dönüşte enerji üretemeyeceği için sapmalar meydana gelir. Ama çalışma mantığı açısından başarılı bir çalışma olmuş. Teşekkürler dostum..

[@burakdemirelli]

Necois Idois kanalın sahibi Türk değil farkındaysan

[@necoisidois7570]

Burak Demirelli, Kankam o benim. Alman. Farkındayım tabi ki kardeşim.

[@turanvarolsun747]

Türkçe biliyormuki bu alman kardeşimiz.

[@necoisidois7570]

Yiğit Alp Karakaş, yok sanmıyorum. Ama Google Translate sağolsun ;)

[@turanvarolsun747]

:D

[@Daytona574]

This is awesome. I have a couple old VCR heads I've considered doing the same to. Never considered 2 of the phases would reverse depending on direction. Time to take a look....

[@Timmymantwo]

Does JLCPcb ship to the UK?

[@greatscottlab]

I think so

[@jort93z]

I think they ship everywhere but china pretty much.

[@Ohm7111]

But shipping is pretty expesive. You will pay 2$ for PCBs and 9$ for cheapest shipping. So they obviously making money on shipping. But still worth it.

[@nightmareinaction629]

Ohm711 if you buy more than one shipping rarely changes

[@Ohm7111]

I am from Europe and shipping on my first order was 8.9$ via China post. Plus 2$ for PCBs.

[@shaileshshukla3610]

2017 ends with this good project.... keep making videos they are the knowledge junction for me... One place to learn a lot in electronics....👌👌👍👍☺☺

[@m.schiller]

German subtilels?

[@greatscottlab]

The community subtitle function is enabled. Feel free to add them.

[@casemodder89]

Arm, das man einen deutschen youtuber nach deutschen untertiteln fragen muss 🙄

[@m.schiller]

casemodder89 ich meine ob er deutsche Untertitel einblenden könnte in den Videos für damit die Leute die nicht so gut Englisch können auch mehr ferstehen

[@konrad759]

casemodder89 Aber besagter "deutscher KZbinr" macht englischen content - warum sollte er auch noch deutsche Untertitel hinzufügen? Die Mehrheit kann heute Englisch ohne Probleme verstehen (zudem ist das im Video verwendete wirklich extrem gut und einfach verständlich). Mit seiner Taktik spricht er einfach die größtmögliche Ziepgruppe mit kleinstmöglichen Aufwand an (obwohl der Aufwand der reinfließt immer noch immens ist...)

[@m.schiller]

Rcmodellbau_DE ich ferstehe ja auch alles gut und er macht das echt gut es wäre nur so eine Idee für andere

[@TheMix1017]

The V-level dependance on speed of rotation is a main problem even with a squaring amps. You will shurely loose some of encrements if apply this as positioning encoder. Look at price of normal optical encoder. It is cheap, precise and perfect. Just use motor as motor.

[@sophiatheodores7985]

i'ts CEOUNTERclockwaise notheng persannel, guod veds as awlays

[@Panj0]

both are fine, what's the problem?

[@mathieuclement8011]

Anticlockwise (or anti-clockwise) is also correct. More common in British English than in American English.

[@0x8badf00d]

* personal

[@sophiatheodores7985]

how thick are you oskar

[@0x8badf00d]

Almost as fat as your mother.

[@jitennagar6846]

Great presentation Scott the way you explain is way better than my professors at College thank you

[@PhoenixNineTails]

I never thought that this kind of things would be possible, I knew that you could get voltage from a motor, but using it as an alternative to an encoder? Dang, now I know what to do with those 2 hard drive motors I've got laying around.

[@teslakovalaborator]

It's not for long-time use,because their bearings(i think they are magnetic) will stuck when spinning counter working direction.

[@RaymondJerome]

a rotary encoder can detect each detent, no matter how fast you spin it. this motor used as one seems like it can get way way out of sync. it should be able to count pole crossings, say 19 for one full rotation no matter how fast you spin it but i think it can not

[@ictrepairs6963]

You really rock man. Keep on creating great contents like usual.... I would like to know more about your background. You use elettronics with extreme confidence making complicate things looking simple. Amazing!

[@republicofsandles]

That could be neat for a lottery device that samples from a set of numbers, or prizes listed as strings.Perhaps with some initial random shuffling of the set, and subtracting a given value once an input button is pressed.

[@republicofsandles]

Wheel...of...Hard Disc!

[@lioneltechreviews9740]

The best video ever from great Scott, this one beats everything you ever published. Kudos

[@dr.projectx5142]

Very neat. Going to use the motor to run the tower fan the motor that It had has gotten stuck and its hard to turn I'll see I manage to get it going. Other wise I'll place in a hard drive motor, great video.

[@mayROBO]

I had a couple of harddisks laying around and I was hating the idea of throwing those motors, thank you so much for the idea. I might use them for some project. :-)

[@BenWillBarrows]

Great! Thank you. I've got a collection of motors of all sorts. Some are like this one, and I now understand how I can make use of it.

[@robertkosmac5971]

This gave me so much joy to watch - I happen to have 3 HDD's waiting my deconstruction ;)

[@robmckennie4203]

The variable doesn't change proportionally to how far you turn the rotor, and if you turn it slowly enough it won't generate enough voltage.

[@gypsyofcruzz]

Can be a great project to create a dj deck player to control the song way forward or backward. Great video by the way

[@lazyh-online4839]

I would personally cut off the electromagnets in the stator and replace them with hall effect sensors so it doesn't matter how fast you turn it, then you can use a program that determines very precise angle changes based on the analog voltages produced by the sensors.

[@fCauneau]

Awesome !! Thanks so much !! We all got zillions of such drives, stored in dark caves, and a-waiting the time we give them a second life. You restore hope ;-)

[@1978jra]

Cool! I have done project where I had leds in a circle and turning hdd motor did light them sama dicrection as was the turn. Purely analog, just opamps and passive components.

[@carmelpatrik]

most anticipated videos ever

[@davethesatellite7319]

Do you think the same methods could apply to a CD drive motor?

[@RetroPlus]

Old hard drives are worth it for the magnets, they are extremely strong. I made the mistake of messing around with them and got a pretty hefty pinch. They are quite useful though for certain things.

[@Makenitso]

Nicely done! HDD motors are good fun to play with, i'll have to mess around with one using your circuit and code thanks :) Oh and good job on the advert, it's rare that youtube ad's are useful

[@jeffbeck6501]

Such amazing video production. Perfect lighting. He's called GreatScott for a reason.