Hey guys
question for the hardware guys.
How can I run a brushless motor without a ESC ? like a CD-Rom brushless motor.
Can I do it with an arduino + h-bridge or maybe an ULN2003A??
Thanks

something like this:
https://youtube.com/watch/...

Oh, and Add HDDs motors on the list... don't know how to drive those too...

in the end you WILL end up with a diy esc solution

you will have to time 3 wave at equal frequency & different phase

bam, you have an esc, albeit maybe a single frequency/speed one

BAh.... There is always a way.

Found it:

https://instructables.com/id/...

when I was about to give up :D

and with my fav h-bridge, the L293D

@GyroGearloose in case you didn't buy in yet, I remember using "HiLetgo A3967" for controlling CD stepper motors when attempting to build a 3D Printer: https://tinkernut.com/portfolio/...

@JoshBent Hum, easydrivers are wasted in this case... and would only "tick" one in every 4 steps. I prefer the L293D solution.

@FrodoSwaggins Well, I already ordered one today after starting this post.
Still, relying on an esc may be the best way, but for some projects may not be the best option. And it's way funnier to find ways to do so, like with the L293D that I've been working with.

Buy Esc or build esc ... i think it depends on your aplication .. if you want to use it for high speed low torque and the torque should not change wildly - small ESC is fastest solution.
But if you want position controll or high torque and/or low speeds like for rc car or simmilar, you need position feedback and those esc are expensive and mainly for bigger motors. In that case your best bet is build. But bldc driver logic is tricky. GreatScott on youtube has nice series on basic esc driving or if you want advanced and butter smooth motion i would highly recomend this blog
http://build-its-inprogress.blogspot.com/...
Look around there and you 'll find great stuff about motor driver theory and practice.

@Chill Thanks :D Already bought my first ESC, but still, ESC is no fun, connect a wire, write some code and that's it...
And, If I want to make a project with an Arduino, 4 brushless and such, I would need to spend 10€ extra in ESCs...
There must be another way to drive them...
ULN2003A doesn't work because it outputs GRD, but I only need to know the opposite of the ULN2003A (that outputs positive) to drive 2 brushless with one chip, plus a shift register maybe...
The idea is, If I'm scrapping, I shouldn't use extra resources that triple the project cost...

@GyroGearloose i can hook you up with some literature that would help if you want. From what you said the most basic trapezoidal controll with 3x half bridges is what you can go for. Simplest, not so effective but it'll get you spining ( badum tss ) :D.

@Chill Thanks :p not a reading guy myself (have memory problems), but could you specify some trapezoidal controls for me to check out?

I've never actually used BLDC's myself, but from what I've read, they require 3-phase AC. Whether that needs to be sine waves or if it could be square waves from MOSFET's, I honestly don't know.. but it'd be interesting to experiment with. Maybe @Fast-Nop or @7400 know more about this. If you end up trying to feed a BLDC motor with square waves, please let me know the results!

Edit: also CD-ROM motors are likely brushed/permanent magnet DC motors despite being advertised as BLDC. They run directly off of the 12VDC rail after all. My 50V power supply also has a fan that advertises itself as brushless.. while in reality it's just a glorified case fan. So that's also just running on 12VDC, without any fancy ESC required 🙂

@Condor phew, motor stuff was in my studies more than 20 years ago, and I've pretty much forgotten all of it except stupid DC motors with brush.

@Condor you don't actually need true sine 3 phase AC .. its just the most efective. My side project now is creating bldc controller like VESC but simpler. To replace steppers in my printer and potentially make reeeeally small actuators with position feedback.
And those fans are actually brushless, they dont have brushess, if you get one apart you will see some chips at their stator base that do the switching ( comutating ) also some hall sensors as feedback position, basically they have ESC built in. Brushless in this case is standart since its long life - no brushes to wear off, even the cheapest ones,
old CD-roms are mostly brushed yes, maybe for the cd spining bit you can find brushless, but HDD are awesome little brushless motors with goergous bearings, just for low torque & load.

@GyroGearloose paper research is where you will find the most information, at least try this https://maccon.de/fileadmin/...
first 7 pages or if even that is too much GreatScott videos are as easy as it gets, also search the difference between Y and delta winding configuration .. some HDD may be in delta and those hobby bldc are mostly Y.

@Chill interesting, thanks for the input! Out of curiosity however, how does the effectiveness get affected with e.g. square waves? Is it less efficient (due to a square wave being pretty brutal to a motor I guess), does it affect the longevity, …? As for the built-in ESC and hard drives, so far I've only opened up simple permanent magnet DC motors and some hard drives. Gotta say, the inside of a hard drive is just marvellous. The smoothness of the platters, the detail on the heads, the beauty of the bearing.. nothing short of amazing how they can even build such marvels of engineering, at a price point of ~€50/TB nonetheless.

@Condor Have to agree... Have around 20 HDDs and CD/DVDs, some already scrapped. That's why I have so much interest in running this little shits with the stuff I already have... especially the cheap stuff...

ok, a question, is there any chip like the ULN2003A that returns positive?
The ULN200A receives a positive signal and outputs GND (7 In, 7 Out) and uses an outside source for the output (500ma each Out).
Is there such chip like the ULN2003A that outputs in Positive (5v to 12v)?

@GyroGearloose: From the top of my head, there's the UDN2981, which is not quite as ubiquitous as the ULN2003/ULN2803. There are probably a lot more.

@Chill: Do you know about ODrive? I stumbled across this one some time ago and it sounds like what you want to achieve.
https://hackaday.io/project/...
Anyway, can you sign me up for updates on your project?

@Condor: Thanks for the tag! All I did with BLDCs so far is bolt new MOSFETs to an ESC, though. So I can't say anything about the control and stuff.

@7400 Thanks... Didn't find the UDN2981 all that useful but turned my search to "pnp darlington array" ... (ULN2003A is a NPN darlington array).
Btw you probably wanted to say UDN2891A, that is a pnp darlington array lol
fuck electronics and their numeric system.

Found it.
ULN2803A
The pnp for the ULN2003A

I have hard time fit everything I want to say to 1000 chars since i've been researching this for past few months , I'm definetly not an expert on topic and motor controll is huuuge topic :D just curious on the power potential of bldc motors

@Condor its just that your torque will not be smooth ... it wil have some ripple that may cause problems in some aplications if its not timed well ... also it will be quite noisy, you can hear that in hobby motors for drones planes etc. but there it is ok because you have high speeds and relatively stable load.
But you can be sure that for products like fans and/or hdd they did their research and chose the right thing and did it well :)
Well if you find dead fan give it a go, its quite different than dc from cd-rom.

@7400 yes i found them also in my research. If i had the money i would just buy their product slap it on printer and its done. But I have in mind aplications where it would be big overkill. Also there are mechaduino and uStepper - closed loop for steppers, that is my plan B if this BLDC path turns out expensive or difficult or just above my free time. For now i dont have any blog page or project log setup but if there will be some great step forward i will tag you here.

@GyroGearloose I'm a bit late since you already bought your first ESC but check if its blheli - compatible. blheli is custom firmware for ESC some come right out of the box with this firmware some not but are compatible, so you can burn them with this firmware and others neither. If your board is compatible you can change some interesting values and tweek how your ESC drives the motor.

@GyroGearloose: The ULN2803A still has NPNs, but eight channels where the ULN2003A has seven.

@7400 OH fuck.... That number really looked familiar....
Oh well...
More NPNs...
just have like 70 chips now.