There shall come a day, where I will understand 100% of the content you post. But today is not that day!

Many people claim that your videos are too complicated but I think that its the way to go. Well... Nobody thaught me about eletronics. I am learning because I want. The thing is that even if the subject requieres knowledge I will try to learn the "basics" and then come back to your videos. I think people should do that. A big part of what I know about eletronics comes from you, because I feel motivated to learn more and more so I can understand better the videos.You are a genius GreatScott! Keep this solid work. You inspired me and a lot of others. Thanks for the effort!

Did not understand anything, but still watched because hypnotized when GreatScott! is drawing his schematics ... Just marvellous !

I am VERY glad that I found your videos. I'm building an vacuum cleaner robot and need to build simple, but powerful ESC. Now I finally understood how to do it. Brilliant!!!

I guess I should add my own comment. First, I just want to say this is a FANTASTIC video and I hope to see more. I dearly wish the people saying stupid things like "duh... just buy a ESC" would understand that the point is to learn and develop new ways of doing things, as well as to understand why ESC's work the way they do. So... Let me be sure I understand: 1. You have to start "open loop" as far as position goes because you don't know where the motor shaft is... you just pulse it and switch the power back off when the voltage rises in the coil. You switch to the next coil after a set time. This is slow, because the A2D takes time, and the speed is pretty much just controlled by the frequency of the coil switches, not by the voltage applied, because you can't apply any more voltage without frying to motor. This is a "stepper mode". It should have good /holding/ torque, but the phases are too far apart to have anything like reasonable /detent/ or "pull in" torque like a regular stepper. The fact that you don't know where you are doesn't really matter because you can't drive the motor any harder anyway... if it's "skipping steps" against a load... oh well. 2. Once the speed is high enough for the magnet to induce a detectable back EMF voltage in the the third / undriven phase, we can use a comparator to trigger on that as our signal to switch to the next phase. At this point, the speed of the motor is controlled by the voltage we apply to the driven coils. As we back off the voltage, the motor moves less quickly to the next phase, and the back EMF spike appears later so we switch slower. Or we apply MORE voltage, not bothering to sense the voltage buildup in the driven coil because we know it won't get high enough to fry the coil or to pull more current than we can provide because it won't have time. The back EMF pulse happens quicker, we switch faster, and so the frequency and speed increase. 3. At some point, we probably can't sense the back EMF pulse quickly enough and we go into another open loop mode where we are just hitting the coils with everything we have and switching based on what we think the motor needs. If we start seeing the back EMF pulses again, then we can switch out of this mode and back down to mode 2. Or perhaps we still see the EMF pulses, but we must switch /before/ they appear. We are only looking for them as confirmation that the motor "caught up" with us. If we wait for the pulse, it's already too late to switch to the next coil. If we go ahead and switch, and the pulse doesn't show up when we expect it, then the load on the motor is too great and we have to slow our switching down a bit to avoid falling out of phase. I'm not sure this mode is actually necessary, but I think it may be why you are unable to get faster speeds. All of that could be avoided if there was an encoder on the motor. In that case, we could simply pulse the coil that matched the current position of the shaft to get started, we could always know when the motor was ready for the next phase, and we would never lose the back EMF pulse as we ran slower or faster. I'm really interested in the use of BLDC motors to make servos. I have a good encoder and some programming skills, so I hope to develop some ideas in this space soon. In the mean time, if you want a fun encoder to play with let me know. They are magnetic, non-contact, and still support very high speeds (28K to 75K RPM) and resolutions (4000 to 360 clicks) and... have a digital mode where you can just read out the current position instead of having to count the encoder pulses. In any case, I'm completely fascinated! The use of the back EMF pulse is such a cool hack and seeing all the complexity of it from your exploration really helps me understand the limitations of this system. THANK YOU!

Love it "...instead of the measuring bullsh!t" at 5:30. Finding a way forward is what engineering is all about!!

I LOVE that you show the troubleshooting process.

You can use hardware comparator that is in Arduino, at least for BEMF - you can attach virtual ground to AIN0 and phases to 3 analog pins and use internal multiplexer to choose which pin to use. It is much simpler and less error prone (PCINT aren't best solution for time-dependent tasks, and driving BLDC is such) than using external comparator. The only thing you have to have in mind is voltage levels, but simple voltage dividers should do the trick. Also you have to have in mind, that drone BLDS can operate at hundreds of amps, not like your small chip can deliver - 4A. Please tak that into consideration when selecting proper MOSFETs in the end of video.

I am not sure if any one else has mentioned it, firstly appart form a very good tutorial, you are only running the motor in synchronous mode. Like a stepper motor, to get more speed you need to increase the frequency. It is not true brushless where the ESC only performs commutation as dictated by motor position and in such a way speed is governed by the voltage applied and the KV rating of the motor. Most ESC's start in stepper motor mode but as soon as the BEMF is sufficient to detect commutation state they switch over to full brushless, which is more efficient. and allows for faster operation. Thank you.

Excellent pair of videos! This was exactly at my comprehension level, and I think your pacing was spot on. Neither boring, nor too advanced/fast.

I like that you took this problem from the very roots, but with better and smarter ic you can control in a much simpler way and more attractive for your viewers.

This video has saved me! I didn't understand why my motor didn't run continuously, and at last I found this video that is the only on youtube which explain why! Thanks a lot

I absolutely love your videos! You have inspired me to learn more about electronic engineering and making something amazing. Keep up the great work!

These two videos were fantastic, even if I'm 4 years late saying so. Thank you for your hard work!

Very well made video, thanks for sharing the steps you went through, and pointing out how hard it actually is to make a good ESC.

Beautiful videos, you pay attention to every small detail. I like those close-ups where you are writting

Hey all! If anyone is thinking about building this, this circuit needs an additional resistor network! I just made something quite like this, using the same LM393 comparators, and my timing was looking really strange, and the speed/torque was a bit lacking. I'm using dual source, common ground to power my circuit, and the motor voltage is around 11v, the rest is at 5v. The motor acts as a voltage divider, making the motor common and coil leads around 5.5v, so what was happening was when the motor started to spin fast, the comparator inputs would get saturated over VCC and on the way back down take a fair bit longer to switch low, making the next step happen much later than it should. I added a resistor network (10k) at the coil sense leads to half the voltage, and then connected the common with 1ks. Now my voltage sits in a happy place between VCC and ground, and the timing is looking spot on. Have fun!

I keep coming back to your videos to see If things you say are starting making sense to me, If they do, then I know I've improved

Thanks for making these videos. I love keeping up with your projects. I hope your studies are going well!

I made a DIY arduino from scratch but this is like a next level! Great job!

Sehr informativ. Der iterative Entwicklungsprozess rund um die Problemchen hat mir gut gefallen.

Hi Scott, thank you for your inspiring videos. This video has remind me two salvaged washing machine motors that I would like to use for something useful. A video series on speed control for this universal motors would be really great, if made it by you. (and I bet would be pretty interesting for all us beginner makers that want to build some useful tools). Thanks again for your videos, I really appreciate it.

Best part of the week when Great Scott! uploads

Best video ever. "Screw the measuring technic" haha! Controlling n Using closed loops systems it's sometimes a big headache. Thank you I've learned a lot about Controlling these kind of motors you really love the subject and share it with us. Greetings from Ecuador.

@5:03 "And that was the moment I said Screw Measuring, I'm going to us an additional timer." Freaking brilliant! =)

Hi, Scott! I love your videos! I really want you to make a sensored version, too! With IR2103 drivers and a hoverboard-like motor

Finally,the weather is decent and i can build some LED Blinker circuits in my garden.Lg from Bayern

Oh my god, I'm really excited for Part3, keep it up the good work man!!!

This man can distroy esc business

Your method to build ESC is combination of reading the schematic + try and error. You not know everything but you believe it is not difficult to achieve what you want. Now I can see your leadership.

IDK if anyone pointed this out yet, but... the ATMEGA328P in the Arduino Nano has an internal comparator between PD6 and PD7 that can request an interrupt whenever the positive input of the comparator is greater than the negative input. Plus, as far as i know, runs asynchronously (correct me on that one, if needed). This means that you could actually measure the current flow using the internal comparator without worrying of it not being detected AND you actually removed a chunk of circuit from your board In fact, the IC in the ESC is (usually) an ATMEGA8 and you can see they use no extra ICs, which is rather impressive, i must say

What just happened. Not into programming and after watching this I now know why. Do like your videos though, keep them coming.

9:28 man I hate this sentece :(

What I'd love to see is an open source esc project for retrofitting brushless motors into electric cars. I think this would really beat the price down making more people give it a go.

Danke,I love your videos. Even though I don't yet use Adrino and I am working on improving my off-grid solar system,I always come across at least 1 of your videos (which are very helpful in my search).

Great example. Really enjoy this channel. The example code on the instructables has a few issues like video says but its a great learning tool. First time Ive used 3 interrupts simultaneously!

Great video! Being a motor control enthusiast everything made sense to me and I would love to make it myself when I have the available resources. Thanks!

I liked the way he used 3 resistors to produce a virtual earth when there was no access to the centre of the windings. Lateral thinking,

Been waiting for this the whole week! Great videos man!!

the only useful channel on KZfaq

you are the best (y) , because you know about electronics - analysis - and programming

As an R/C amateur, I thought I'd drop by this vid and learn how the ESC on my cars works, but now I feel I need an electronics degree and possibly maths as well

Really fantastic work, man!

German engineering in action!!!! Fair play to you!!! I wont be building an ESC but really enjoyed the videos

My god, I think u can see the electrons flowing through the wires. I am learning so much from you. God give u a long long life so that you continue to upload such videos. A request. Pl, do make the videos a bit more explanatory for ordinary mortals like me........

Never can miss a video of yours

The man is a genius !

Great video, as always. I hope to see a future video where you develop a more powerful board!

Excellent presentation. Keep up your research work. Zero crossing is the solution as you set in your last version. Liked your video.

anything compiled in the arduino ide will be useless for high speed real time reactions like this, it produces stuttering bloatware MS would be proud of, hand coded would be so much more efficient, and so much more complicated. What you have achieved here is simply amazing

Wow, you did some great work with the MCU timings. You may need a FPGA or CPLD to meet tighter timing constraints, but maybe the FETs will be enough for this. It will be interesting to see this project take off.

Great job, not easy to make that motor spin. A lot going on. I don't where you find the time to do all this while working on your advanced degree. Your going to be an excellent engineer.

Useful project, let me learn more and more and this is the most important thing.

Hey this landed perfectly for me, thanks for the level of detail and great process

This is great. I would love to see more about getting your custom ESC closer, or even superior to the commercial one.

things like current limiting and BEMF feedback had been recurring problems in my hand-made motor drivers. I had tried doing BEMF sensing/... via discrete transistors (ex: 2n3904) but with limited success (don't have opamps or trimpots; mostly tried biasing things via voltage dividers). recently put this on hold as this stuff eats a lot of money and components (more so when accidentally blowing up comparably expensive MOSFETs and similar). I had admittedly had more success for some stuff basically just using stepper motors and computed duty-cycles and speeds. for fastest speeds with steppers, generally had best results with both phases active at a time and using a variation of reverse-sawtooth waves (square was better for torque but limited to low speed, sine wave made motors run quieter and cooler, but had neither great speed nor strong torque). in code, could switch between driving waveform and duty cycle values and similar based on target speed (except on some MSP430s I was using, where the drivers were pretty limited due to the 2kB ROM size limit).

"And that's a subject for another video!" this means the tutorial will come up soon (2022)😉

This was a really interesting pair of videos. Great job explaining everything. I'd be interested in a high power high voltage ESC design for E-bikes or similar

Sir what level of knowledge 😲

Great video waiting for part 3 👍

And this is why people need to learn to solve problems with circuitry other than microcontrollers...

I made very basic raspberry pi ESC with python. This video solve my problem that motor get stuck when it is in high speed.

>>> made own 3 phase controller from osc ( 74hc14 / 555 ) 74hc393 ,74hc138 74hc30 - 2n7000 - got plenty of these if it 'blows' - not a problem

"Hm it doesn't work but it should. Fuck it, I'm just going to hard code it with a timer." This is programming in the field of automation.

the inability to achieve high RPM also comes from the limitations from MCU. To achieve high rpm, Phase Advance method is used. Microchip has a nice application note on sensorless control

Great Scott, I think you might want to to consider lighter motors and a different structural material, considering wood has a high wind resistance therefore require more thrust

Great Stuff. Nice mix of basic and High Level. Great Quality!!! More please

waiting for that more powerful ESC that you were talking about at the end of the video.

that was cray cray! But well done on doing it!

Ok, take my subscription, you genius, you!

Cool project! I watched the video several times to understand how to control a BLDC motor. I always confused ist with a synchronus motor which needs three sine waves. But i'll use an other microcontroller. I don't really like Arduino because the most people never reads datasheets or know how a microcontroller works. They simply use all the libraries without understanding what's happening. I'll use a PIC18F4431 microcontroller that has a special hardware to control BLDC motors, with integrated timer for the rotation frequency and another one for the PWM.

Great Video !!! Comparators bounce like a button causing many interrupts in zero crossing areas, i couldn't find a stable solution for that. Ps. Please use something plastic while showing oscilloscope screen, screwdriver will scratch it.

That's why I just get ESCs off the shelf, very interesting try on your part though.

Just buy a BLHeli_32 ESC and be done with it. That being said, thank you very much for clarifying the basic operation of ESCs in a fairly simple manner. Keep up the great videos!

love from INDIA. Great work nicely explained.

i want to be able to control a Hoverboard motor using my own components, and now i at least know that hall sensors are not necessary, but will be handy when controlling it

I like this now I am a big fan of yours

I dont have any idea what he did in the video but I watched the all of it😂 Like if you agree

Heatsink the DIP package and it might work better. Great videos!

@phu cao Peak current are momentary and they don't damage the devices till you reach maximum peak current rating and every power device has peak and continuous ratings.

Why don't use arrays for the states, instead of switch with functions?

Considdering that most quadcopter esc's are 12A or more each, and your build will weigh much more than most racing quads then i would suggest that you beef it up to handle atleast 12A if you want to have some power left to save yourself from a hard crash. Most of the times my quads have been broken were when i didn't have enough lift to pull myself out of a bad situation.

Still waiting to see the better version esc; and very good video 💛

Great videos, concise and packed with juicy info....! Even though I have experience with microcontrollers and driving motors, not being an electrical engineer, I can't profess to understand everything here on a first viewing. Probably benefit from a slowing down by a factor of 2... 😜

This project is so cool! Really informative debugging!

It's a very good video , I like it a lot .You did a very good job

I watching your videos, craving for a new one! Thanks for the surprise 😊

You just saved my thesis.

Communication take place after 30 degree of zero crossing. Not at the zero crossing

@9:28 Is it time for that video, yet? Really interested in utilizing reverse as well as seeing what kind of power is possible with these mystical new components.

@GreatScott! your work is fantastic, but scary when you one realize that his/her school project relays it.

I understood just enough to be awestruck!😂

I've seen a lot of your videos... But now my brain hurts a lot

was eagerly waiting for your video ,good job

“Instead of the measuring bullshit” hahah

Best xplanation BLDC Moter and ESC circuit

Greatly appreciate your details..Many Thanks, God Bless 🙌

was going to say you needed external switching mosfets.... that IC was never going to handle the load

Another great video, Scott! ;)

Scott, I think I may have found an error in your explanation or I don't quite understand it. At 0:56 you show how you activate the corresponding low-side FET to short the coil with itself, reducing the current flow. If A-HI was high and turned off at threshold value, switching it off makes sense because it stops the current flow. However, opening A-LO makes no sense in that case because the current would be allowed to flow in the direction you've drawn anyway, because of the body diode of the MOSFET. It seems to me that, instead of what you were explaining there, you would like to switch the high-side MOSFET at threshold value, and switch it on again once the waiting time has passed, and leaving the opposite FET on to allow current to flow. Activating the corresponding FET does not make a difference (because of the body diode), and disabling the opposing FET could create a spike in voltage that could kill your FET (I do think the body diode of the opposing high-side FET allows this to dissipate but if not, breakdown voltage is easily achieved). However, maybe I didn't understand your explanation right. Could you give me an explanation on this matter?