Xiaomi Cyber dog geared motor ~$60

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I’m sure you could hop on alibaba and find something, or at least the planetary gearbox, probably for $5. Pair it with a gimbal motor for $15 bucks (5 on aliexpress, but those are random motors, however they are similar enough it’s reasonable to change a cad file to match them as needed). Then I would print the casing with CF reinforced Petg or something (higher heat resistance). Probably adapting the interface to the gearbox would be the hardest part. And the output of the gearbox to your application.

But sure if you can get these it looks good for some stuff, until you can’t. I just generally object to the pattern that I often see in hobby communities of grabbing consumer stuff. When it’s just individuals, you really have no choice. but with a community, and the prototyping for electronics boards and even limited mechanical stuff (3d printing and a good selection of parts), we have options, now. We don’t need those nasty polluting people that keep designing things to break, or not as much anyway.

To be fair there are a few cases of repurposing that went fairly well and you can get a pretty good price point esp for used items if there are a lot kicking around on the used market. Still I dislike the casino roller coaster nature of the whole thing. The really good stuff comes from patient construction of good stuff, like simplefoc and hopefully the boards for it that are in the works.

Exploring the idea of a printable harmonic gear might be legit. Perhaps with very fine layer heights to get a smooth surface (I am doing a part with 80 micron layer height right now and have done 50), adequate lubrication and cf reinforced filament it would be practical to concoct a good actuator starting with a gimbal motor. I’m not the person to do that though because I don’t know anything about these actuators, I have become something of an expert on cheaply printing relatively good mechanical parts though.

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To play the devil’s advocate for a minute: communities are made by 1% contributors and 99% lurkers/users. Once the few critical contributors stop their work or move on to other areas, two things happen: either the project dies or it forks into multiple irrelevant streams. In a few cases, the forks take off and become better, more frequently it’s a slow death. I used to own a few Devo RC radios (for drones/RC models), and the open source DeviationTX was incredibly useful, ran on the highest number of radio hardware and supported the highest number if protocols. Around 2017 started shrinking, and by 2019 was completely dead. Yes, in theory, I could build my own fork, in practice it’s a major work to just get something building.

People, even hobbyists, have a problem they want to solve. Then they start looking for tools to achieve their goal. Today, SimpleFOC is awesome if you have a lot of time, are willing to find out which board t buy, then find a motor, then find the gears. Almost nobody has time to 3D print the gears and assemble a working unit. But even with open source drawings and a shopping list, either the cost is very high or the specific motor needed is not available anymore. Look at the smatknob project GitHub - scottbez1/smartknob: Haptic input knob with software-defined endstops and virtual detents which was dead for the longest time until Sparkfun stocked the motors. The moment that stops, Smartknob will be unfeasible for most people.

Having a $60 off the shelf motor today with the risk of disappearing is much more appealing to most people than a kit composed of an open source driver that might or might not be available, plus a lot of 3D printing using hard-to-find filament and a motor that might not have the same specs, and still spend much more than $60. The fact that I can manufacture my own driver board if I wanted or source a different motor then adapt all the 3D printed files, is simply not a good enough reason to switch from the $60 motor.

Hacking consumer electronics available at bulk prices is one of the advantages of today’s economy. I’d rather spend some time figuring out how to port SimpleFOC onto the Xiaomi controller, then use their motor, than spend the time on a fully open source solution. In 5 years, chances are, neither will be available to buy anyway.

I see where you are coming from, and I have a lot of respect for your position. But it’s not what the majority of a community usually wants. Give them a $60 motor and a youtube video on how ot hack it, and they will be much happier.

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IDK the real internals of ebike hub motors, but the smaller ones come with a planetary gearbox, too. But in their case the housing (orbit) rotates.

//edit here’s another surplus motor for cheap
but it comes without Hall-sensors

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Until it goes away, that’s the thing. Then the cycle repeats, and there are long periods where people do not in fact have what they need.

But I guess the thing is they don’t actually need it, it’s just a hobby, so it’s fine.

But the core of what I’m saying is that the total quantity of labor effort is basically the same either way, over the longer term. And the plan-steer-do approach does tend to actually work better, whatever you are after, than the reverse-engineer-shimmy-into-a-role-lose-everything-pine-for-a-long-time-repeat approach.

BTW sparkfun doesn’t usually stock the motors, they are usually out of stock. And the thing is the way he did that is exactly the approach I am arguing against and the approach I suggest would have avoided his issue entirely, and been a lot less work. I have read closely on that project and it’s history as I was working to track down a good motor.

He did the same thing and made the same mistakes at multiple levels. The motors he chose were random motors he could get for cheap, but he was not careful to be sure he could get more in the future. He designed around them then his design was useless later on, but also he didn’t do a modular job with the design all the way down, thus it was a big deal to redo the CAD files to change to a different motor.

He also could have just contributed to SimpleFOC from the beginning and then used that as a module. Instead he re-invented a lot of the stuff and just put it in his own code as a big hairball, which nobody else can use for much (unless they know a lot about it already and can pluck the sections of code out).

He may or may not have done basically the same thing with other components like the screen etc., IDK, I haven’t looked at that section of things.

It’s great there is a community around that though, I would never have expected that, but with the labor effort that goes in they could have done a hell of a lot better stuff.

edit: apparently they got those motors back in production, but it was like more than a year where it was as I describe.

p.s.

I guess the whole focus on only taking made in china type things and working backwards, and always being confined by that paradigm is a sort of forfeiture of our own abilities. It’s the forfeiture of potential, as if we didn’t know how to do anything or have the ability to do such things.

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My feeling on this discussion is that most of our users are not designing products around SimpleFOC, but rather projects. Please correct me if I am wrong.

For someone making a product, your point of view makes a lot of sense, @Anthony_Douglas .
But for someone who is just doing their project, usually for fun or for learning, its a big ask to want them to contribute, and to want them to make a motor themselves that they can get for $60. Even if it’s not available in a year, why would the project-maker care? By that point they’re done and working on their next project…

But above all, I don’t think it’s an either-or situation. I think some of us can buy $60 motors, because that’s right for them, and others can work on a Canadian/US self-produced motor, because that’s what they feel is right for them.

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There are some interesting examples of hobby communities collaborating on good stuff which then rained down benefit on others in the community. Bl_heli_s is a case right at hand, even. I just think it’s a good idea.

I can certainly see the tendency not to in action, not denying that tends to happen or the underlying mechanisms, but honestly the mechanisms are largely a cultural thing/what people choose to do and how they do it. Grab easy stuff and burn it up, producing trash in the process… then repeat. Everybody for themselves, get some jollies quick and cheap and move on. It’s not really working out for anyone.

I don’t believe in the idea that doing X for fun in a way Y is unassailable.

I see something even worse in the 3d printing community. A hyper focus on cheap crap on the one hand, on the other they spend actually a lot of money, mostly producing trash “for fun”. I honestly don’t think they are having that much fun anyway, they just don’t even know how to have fun. Even the slightest suggestion of actually undertaking the challenge of trying to transition to compostable plastic for instance, as a hybrid fun and also worthwhile idea, is met with surprising rage and even hate, even if it doesn’t cost a dime long term.

IMO even hobby undertakings are enhanced by community, collaboration, and actually accomplishing something over time…

I’m not advising against grabbing some cool motors while you can, but spending a lot of time reverse engineering them baffles me, because the same skill set can be applied in an even more fun and rewarding way… In a way it’s all good, but actually that’s the thing, not really because there is a lot to do and not everybody is on cloud nine. If we already lived in some kind of post scarcity world then ok, but this polarity with trying to do things on the cheap on Monday because we can’t afford to have fun, then wasting tons of time and money on Tuesday does not strike me as the road to happiness.

Not that I’m trying to impose anything on anyone, just saying.

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Not everyone has the same skill sets. For a mostly software guy like me with no 3D printer or mechanical fabrication tools, reverse engineering somebody else’s electronics and porting something like SimpleFOC is enormously more appealing than an open ended project where I cannot contribute much, and where I can’t build what I need today.

If I wanted to build, say, a robotic arm, today I’d buy a Xiaomi motor and see how hard it would be to port SimpleFOC to it. Look at the efforts to port SimpleFOC to the hoverboard controllers (Candas&others). It’s purely software and benefits the community, even if there are a lot of different incompatible hoverboard controllers.

BLHeli started as a project to replace crappy ESC firmware with better ones. If anything ,BLHeli disproves your point :wink: The BLHeli people didn’t start by designing and building better ESCs, but as way of hacking the early, cheap Chinese ESCs. Over time, they influenced the electronic designers to build better hardware optimized for BLHeli. BLHeli is the equivalent of hacking the Xiaomi motor.

I agree with your aspirations that it would be better in an ideal world, but people skills and timelines make a difference in how they approach a problem.

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Slightly more expensive than anticipated, but now on Aliexpress for £75/ $88

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~Bump~
Does anyone have news about the motor? Build quality, backlash or connectivity of the controller?

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I see people on Twitter playing with it, mostly Japanese users: x.com

I think they are all using the standard driver/ CanBus comms? GitHub - CmST0us/CyberGearKit: CyberGearKit is a framework of communicating to xiaomi CyberGear.

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@Karl_Makes_Music didn’t you order some of these? did they come?

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Yes but stuck at customs.
Lack of CE markings. They will release it but unknown when

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@Karl_Makes_Music

Which exactly is stuck at customs? The xiaomi motor? Any link to the product?

Cheers,
Valentine

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Sorry yes I mean cybergrear Xiaomi motor.
I’ve gotten it via my middleman in HK. So it was not direct purchase from link

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@Karl_Makes_Music
I am willing to order one, and see if it could be reverse engineered for SimpleFOC, and even build a PCB driver to replace the original if it cannot be re-flashed with SimpleFOC, usually this takes a weekend for me.

Give me a link, I’ll order one.

A PCB driver for something like that would fit around $10, probably based on the QVADRAN so seems like a good compromise.

Cheers,
Valentine

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Now we’re talking :slight_smile:

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The price has risen since I first saw it on Ali…

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Did you find anything about the communication protocol?

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I ordered one and got it a few days ago.

The instruction manual contains a link to a zip file with some documentation, but it’s all in Chinese.

https://kpan.mioffice.cn/webfolder/ext/3UN9fi%24e4us%40?n=0.28807380129881804
The password is QDD1

This contains:

  • A 3D model of the motor
  • A PDF with some documentation about the motor and the CAN protocol
  • A debugger application. This works with a very specific Serial to CAN adapter which uses an AT command set that doesn’t seem to be documented online. I ordered one of the adapters, but it will probably take some time to arrive
  • Firmware images for the MCU in the motor

I attempted to talk to the motor, but accidentally sent what I think is a encoder calibration command, which seems to have wiped some configuration from the MCU. It seems fixable, but I believe I would have to use the debugger application. Will need to wait for the Serial to CAN adapter to arrive.

There is also an implementation of the protocol in this repo CyberGearKit/Sources/CCyberGearProtocol/src/cyber_gear_protocol.c at main · CmST0us/CyberGearKit · GitHub

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Here are some photos from inside the motor, it seems very nice. There is a plastic cover on the back that is removable with 4 screws, contains the PCB which is also removable with 4 screws. The magnetic encoder is mounted on the bottom of the PCB.

Here are some photos of the insides of the motor: https://photos.app.goo.gl/6uJsaHoJMCjojpV56

It has a GD32F303 inside, which is (mostly) compatible with the STM32F303. It should be very possible to port SimpleFOC to this board

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