Has anyone used brush motors for multirotors?

Has anyone used brush motors for multirotors

Probably Why do you ask? [e.g. weight of motors, control of motor types, efficiency, life time, noise production etc...?]

Brushless motors are used (almost?) exclusively for this type of machine since they have a better power/weight ratio than a brushed motor. I suspect that performance and flight duration would be substantially compromised with brushed motors.

I fly quad and hex copters and have never seen brushed motors used all for the same reasons given by @goom.

Tiny DC motors are used in the very small micro quads, and indeed in the micro helicopters, but just about everything else is brushless these days, for very obvious reasons.

Whats the connection to PICAXE ?

Brushless motors are a type of 3 phase motors, so speed control is much more precise and stable under varying loads.
That is the reason most quads/multirotors of any size use brushless, in addition to the above statements.

thnx for all the replies - yes, I know it's almost all brushless -- NOW those expensive ESC's - do we have picaxe programs
to drive (thru appropriate drivers) the brushless motors. I want to start writing my own programs. I have written
pgms for STEPPING MOTORS. So back to the software and hardware necessary to sequentially activate those COILS
on the STATOR. However is my picaxe fast enough ? I use 14M2.

Where do you buy "expensive ESC's"??? You can buy many a high current ESC (electronic speed controller) for $10US or less on HobbyKing website.

Why try to reinvent such a ubiquitous device?

thnx TEX - $10 does sound better than I have seen -- I really enjoyed
a primer for *newbies* which was referencing HOBBYKING --
I disagree with u a little -- REINVENTING things can be the greatest fun
of all (take it from an 86 yer old ) - the universe is our plaything !
thnx

larryatheist said:

I have written
pgms for STEPPING MOTORS. So back to the software and hardware necessary to sequentially activate those COILS
on the STATOR. However is my picaxe fast enough ? I use 14M2.

Click to expand...

I would start by assuming you need a reasonably powerful Microcontroller, programmed in assembler or C.

Driving a brushless motor is a good deal more complex than just switching the coils in the right sequence, for instance you need some form of feedback to know the rotor possition and make approriate changes to the way the coils are driven.

I have been looking into this a little bit, but never considered using picaxe connected to the motor directly (i.e. through transistors). There are driver ICs out there that seem simple enough for a host MCU like picaxe to operate. Here are a few:

http://www.marvell.com/power-management/fan-controllers/assets/Marvell-88EM2269-01-Product-Brief.pdf
http://ww1.microchip.com/downloads/en/DeviceDoc/25003B.pdf

These are tiny, but I'm sure google can help you find more once you get acquainted with terminology and what to look for.

With that said, re-inventing things often is THE fun .


Good luck,

Edmunds

"Re-inventing" doesn't describe what we all end up doing. I believe the word used should be "re-applying." Yes, there is satisfaction in re-applying "things" to function in ways that are different. Of course, we see it all the time on this forum.

larryatheist said:

So back to the software and hardware necessary to sequentially activate those COILS on the STATOR. However is my picaxe fast enough ? I use 14M2.

Click to expand...

That's hard to answer without knowing exactly how the motors are to be driven and controlled and how much work you have to do to achieve what you want, how many motors are to be controlled and what else you are expecting your PICAXE to do.

The less a microcontroller has to do the better it will usually be at doing what it does. Having separate PICAXE for each motor and a central controlling PICAXE may be the best approach.

It might be possible to go down to 08M2's for some tasks, or conversely might require going up to 20X2 for higher operating speed, or even an over-clocked 28X2. In some cases the task may be too extreme for any PICAXE to handle.

thnx SRNET -- I am listening to a need for fast micro-controller and avoiding interpreter Basic because of its slowness. also verifying position of coils ala server motors.
By the way my take on these things is autonomous flight sine RC, software in control. My HELLO WORLD will be start motors, ascend five feet,hover one minute, descend ,
land, shut engines. However, easy to talk the talk, but harder to walk the walk !

thnx HIPPY
Don't know if u read my last post - it may answer some of ur questions.
In all my experiments I just want something to work - even cameras are not on my mind.
Certainly not aerobatics! some will say sine RC ur illegal. Depends on the range of
my experiments. Same way u can xmit radio sigs under 100 milliwatts.

EDMUND mentions drivers. My favorite has always been ULN2003 or variations.
it sinks half an amp

larryatheist said:

By the way my take on these things is autonomous flight sine RC, software in control. My HELLO WORLD will be start motors, ascend five feet,hover one minute, descend ,
land, shut engines.

Click to expand...

So you also need stability control as well ?

I doubt a PICAXE is fast enough, although this role for a PICAXE is often suggested on here.

Maybe if you could make the PICAXE run somewhere between 100 and 500 times faster ?

larryatheist said:

thnx SRNET -- I am listening to a need for fast micro-controller and avoiding interpreter Basic because of its slowness. also verifying position of coils ala server motors.
By the way my take on these things is autonomous flight sine RC, software in control. My HELLO WORLD will be start motors, ascend five feet,hover one minute, descend ,
land, shut engines. However, easy to talk the talk, but harder to walk the walk !

Click to expand...

Larry, Forgive me for sounding like the proverbial wet blanket but I'm still not convinced that you grasped the size of the task that you are attempting.

The only way that these devices can stay in the air is through some quite incredible software, which takes thousands of hours to develop.

The stability of the craft is what takes all of the work. Think about how you would apply constantly changing proportionate control of multiple motors in response to the output of a thee-axis accelerometer.

thnx INGLE -- I do realize there is sacrosanct tons of software - this is wonderful ! algorithms for movement of multirotors, just for one thing, have been around. But also
the long string of sensors - say from SPARKFUN (and the great BREAKOUTS - doing some of the nasty work of I2C serial stuff) pressure, range finders, magnetometers,compass, gps, ir obstacle detectors -of course this is scary! Just talking to u guys is allowing me to savor (or savour) all the technology that's gone into drones and multirotors and their ubiquitous presence ! If EDMUNDS is listening, my wife ILZE was born in RIGA sept 1, 1941. Greetings.