Open source brushless motor controller

It’s been a long time coming, but efforts to create Open Source brushless motor controller are finally paying off.

The Open-BLDC project aims to create an open source motor controller for the brushless motors usually found in remote control airplanes, helicopters, and quadcopters. Normally, these motor controllers – usually called electronic speed controllers – can’t supply more than a few dozen amps, and are usually only controllable via a servo signal.

The Open-BLDC goes far beyond the capabilities of off-the-shelf ESCs with up to 200 amps of output, TTL level serial input, and the ability to use regenerative breaking.

While the Open-BLDC project is far from complete, the team working on the hardware hopes to add I2C, CAN, and PPM interfaces, along with speed and torque control.

There is no word on when, or even if, the Open-BLDC will ever be available for sale, but with the features it has it would be welcomed by just about any builder constructing a gigantic RC vehicle.

27 thoughts on “Open source brushless motor controller

  1. “Normally, these motor controllers – usually called electronic speed controllers – can’t supply more than a few dozen amps”

    Not true. Most brushless controllers found in the r/c industry can handle 50+ amps with 150+ being common place.

    1. For en electric car, we need much much more!

      Think more like 100,000 Watts of peak power. Your typical brushed golf carts can take 200-400 amps just to get going. Peaks in EV are often well over 200 amps for about a minute.

      I would however strongly suggest reading up on this beautiful project to learn how to build your own BLDC controller for an EV.

      1. True, but the EV design I’d like to experiment with would have four smaller motors. This controller might be just large enough, I think.

      2. 100 kilowatts is quite a lot of power compared to most DIY EVs, though I could see commercial cars using that much or more. A 200 amp controller should be more than enough for a golf cart or even a small car, assuming it can handle enough voltage.

    2. It might be enough for an electric bicycle/scooter – I’d want a fair bit more power and safety margin for anything I’d consider taking on busy streets.

  2. Cool project from an ace team, but as far as I can tell there’s been no action in the past 18 months. Why was this highlighted today?

    1. I concur. Since i’ve been looking into building my own brushless motor controller, i’ve come across this project. Just like many open source software (i know this is hardware + supporting software) project, this is on ice or near death. Interesting project (past and present) regardless and much can be learned from, but doesn’t change the project’s overall ‘health’.

      1. Yes you are right the Open-BLDC project was in hibernation for quite a while. (about one and half years) But I intend to revive it again. (working on that goal since about three months again :D ) I don’t know why the Hack a Day guys decided to feature OBLDC today either. But I am glad they did, good source of motivation.

        Also Open-Source projects heavily depend on the amount of people involved. Open-BLDC is a very small project with only very few people. It did not reach the critical mass of involved people yet to survive the moments when few of the community members are busy with other things.

        We are happy to see more people actively involved in pushing the project forward! Just drop me a note! :D

  3. Open-BLDC is no longer being developed and this ‘news’ is more than 2 years old. The author moved in a different direction, switching to CLogic.

    1. It is being developed again. Look how old the github commits are. Not enough time to keep the wiki up to date though. That is right. :D Drop me a note if you want a wiki account to help with that! :D

  4. Wow that is a very old post of mine. :)

    Currently we are working on a bit different goal. Trying to bring more sophisticated control and interfaces into more hands by making a cheap small controller for small quads: http://open-bldc.org/wiki/Strip

    And also a motor simulator that can run the controller firmware software in the loop. To make development and debugging easier.

    But yes one could use a later version of OBLDC called CLogic as a replacement for the control board in Castle Creations motor controllers. But that is not the main focus at the moment. :)

    Join us in #open-bldc on freenode or the mailinglist. :)

    Cheers Esden

    1. That looks like a much better size. When I saw the photo I was like. “Too large, too heavy”

      (I fly model gliders where brushless motors with light weight motor controllers and battery packs are often used to get in the air in a simple way)

  5. Uhhh, 200 amps? What? At what voltage? — I have to use 16 gauge wire on my reprap for 4 amps @ 12V. I’d be pretty surprised if that little thing could pump out 200 amps continuously at even 3 volts (that’s 600 watts!)

    1. That was my first thought too, after looking at this tiny board with even tinier wires attached.

      Maybe it’s only for brief transients, the same way cheap car audio amps are rated.

      1. The rating is not related to the power stage shown in the picture of the article. It is related to the CLogic Open-BLDC logic board mounted for example on the Castle Creations Phoenix ICE 200 power stage. :) With adequate cooling this setup actually can dump 200A continuously into a motor. The powerstage in the picture can only handle about 25A.

  6. I found osmc very cool, there’s lots of example pcbs in the files section. Though yahoo sucks.

    http://tech.groups.yahoo.com/group/osmc/files/

    Open bldc is a great project but I don’t think it’s suited to rc cars, or particularly easy to build. I could be wrong though!

    If I was gonna order one from a pcb house tomorrow it would be this one:

    http://danstrother.com/2011/01/12/brushless-dc-motor-controller-board/

    While low current it might cope with a 17.5t motor with a hsf attached to the pcb…

    How do you make pcb tracks take 150amp At 7.4v or 11.2v? Do you split across many layers or something? Because you can only solder to one layer. Most calculators show the traces would have to be 1m wide or something stupid like that!

    I’ve seen people soldering wire to their tracks but that’s too ghetto for my liking!

    1. Most of those calculators determine acceptable widths for long runs. If you minimize the distance that the current has to travel (and maybe add some heatsinking/airflow for good measure), you can get far higher numbers than those tools suggest.

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