Brushless motors in the lego world - general topic

[janssnet]

19 hours ago, gyenesvi said:

If it was a bigger/heavier build, 4-wheel drive, with large grippy tires, then I could easily imagine that gear connection skipping.

Do you have some links to the motor/ESC you used? Are the motor mount holes 16mm apart? And what's that connector trick you use for the motor cables? Looks interesting!

Would be good to do a load test for this mount. Let's see if I can come up with something coming weeks.

And yes agreed, when the load/weight increases, you would need a gear train, ideally with some planet gears to divide the torque properly.

The motor is a very simple 1750kV outrunner. Mounting holes M3 - 16mm apart, of course :) 

Advantages of this motor: cheap, no cooling required (under normal conditions) and the motor shaft can be shifted, allowing you to mount the motor on the front or rear side.

https://nl.aliexpress.com/item/4000121770043.html?spm=a2g0o.productlist.main.13.57bd7392rPapJu&algo_pvid=4f7ea6c9-bad3-4525-9324-cb00b53439e6&algo_exp_id=4f7ea6c9-bad3-4525-9324-cb00b53439e6-6&pdp_npi=4%40dis!EUR!3.89!3.89!!!4.09!!%402103847817019402965684078e398d!10000014597782070!sea!NL!173983871!&curPageLogUid=JhLCITsdifaM

Regarding the connector trick ... well spotted ;) If you use 3.5mm bullet connectors and isolate them with heat shrink tubes, most of the time, you end up with a connector that fits the 4.8mm LEGO hole perfectly. Depends on the thickness of the tube.

 

Edited December 7, 2023 by janssnet

[Krzychups]

Hello!

I have made a lego 5x7 frame with bearings. I don't know if someone has done something similar because I am new. I use those bearings. At the moment the bearings are not glued. I haven't got a 3d printer so don't ask about 3d print settings. If there is something to improve feel free to tell me!

A tip: if you don't know the dimensions of bricks:

• export the brick (the file) in Studio 2.0 as collada file (.dae),
• import the collada file in Blender,
• go to modeling and use the tool "measure".

Download stl file here.

You can see more photos on my Flickr.

dimension tip by Krzysztof Czech, on Flickr

20231215_210538 by Krzysztof Czech, on Flickr

20231215_210351 by Krzysztof Czech, on Flickr

 

Edited December 16, 2023 by Krzychups

[Aurorasaurus]

4 hours ago, Krzychups said:

I can't upload the .stl file because it weighs too much, can you help me, thanks?

 

you can put it on bricksafe and send a link

[Bensch55]

On 12/15/2023 at 9:19 PM, Krzychups said:

I don't know if someone has done something similar because I am new

Yep: https://tf-engineering.at/diffcase/

Printed in SLA to have an injection-mould like surface finish.

[Tekhneblr]

On 10/27/2023 at 10:29 AM, janssnet said:

Great subject folks!

In case you're looking for (more) inspiration how to mount BLDC motors to LEGO, please find a few additional suggestions hereunder.

 

‎LEGO BLDC.‎001 

‎LEGO BLDC.‎002 

‎LEGO BLDC.‎003 

‎LEGO BLDC.‎004 

 

 

Hello!
Thanks for these great ideas!
Where did you find the "in-wheels" motors (E) ?
Tekhne

[Brano]

Hello!

I would like to ask I bought geek servo, 2s brushed esc, 2s battery, rc tx/rx

And I am not able to controll motor and servo together (really strange behaviour) please check video and advice. I am new to rc components but not to LEGO. Am I missing something? 

Thank you for you time and advises.

[Ryokeen]

@Brano

First i would try to switch channels, just to see if there is anything wrong with the receiver.
Then you can check the manual of your reiceiver/transmitter, as some need to set endpositions for an esc.
Then there is the possibility of a faulty esc.
Might want to post which esc you use ?
 

[Brano]

@Ryokeen esc is A2 30A ESC Motor Speed RC ESC 2KHz Forward Reverse Brush https://a.aliexpress.com/_EyDb5kD

I tried 3different(cheap) esc and behaviour very similar...

I will try to check options on rx/tx(options are st_rev/th_rev, st_dr/th_dr, st_trim/th_trim)

Also i noticed when i turn servo to left/right -> xl lego motor beeps 5times (via pwm?)

Thank you

 

 

 

Edited January 12, 2024 by Brano

[janssnet]

First thing that comes to mind is that the ESC is not 'armed' properly. Meaning that the ESC has not gone through the initialising process properly when being turned ON, and therefore doesn't know which PWM values are 'neutral'.

Please have a look at the ESC's manual (if available) to learn about 'arming the ESC'.

Sometimes these ESCs want to receive a max throttle signal at start.

 

 

[Brano]

@janssnet i tried different esc and according to yt videos no arming is needed for these escs. But i tried max throtle, min th and max and min 😀 no success.

Motor works ok, servo works ok but when i touch servo-> motor is no longer working i must turn off/on esc and motor works until i again touch servo...

Simply they are not able to work together...

 

Edited January 12, 2024 by Brano

[FriedlS]

That is crazy. Maybe your geek servo is faulty.

Look here:

 

 

Edited January 12, 2024 by FriedlS

[Brano]

@FriedlS I have tried 2 new geek servos, 2xl motors, bugy motors 3different esc... Everytime behaviour is quite the same... Am I crazy? 😀 What Am I doing wrong?

[Ryokeen]

@Brano rly weird. As you switched motors, esc and servo, the only constant is the transmitter and receiver. What i've noticed is that first if you use throttle the esc lights up so it get's a signal. After you used the servo, it does not or get random signals. I once had a similar behavior when i used the wrong channel on the receiver. I had a simple power switch attached that can be switched with a servo signal. It behaved very randomly cause i had it on a channel on the receiver that was not actually in use on my transmitter(6channel receiver, 4 channel transmitter). So that or some transmitters have mix modes for tracked vehicles where chan1(throttle) and chan2(steering) are mixed to drive 2 esc. Maybe check if your transmitter supports that and has that enables.
Else i could only guess that the transmitter/receiver pair is faulty.

[oracid]

Sorry if I'm missing the point.
I'm missing something in the editing of the first video.
I can clearly see the 3-strand cable from the geekServo to the receiver, but I cannot see the 3-strand cable from the ESC to the receiver.
Could you make a new video, but spreading out the connections so that we can better see where the cables leave from, and where they arrive.

[Brano]

@Ryokeen I bought tx/rx as a bundle(new) 4ch rx and tx.  According to website it should support mixed channels but i didnt receive user manual...  I have tried every option but without success

 

@oracid new video uploaded

 

[oracid]

Thank you for the video.

Nothing obvious !

Did you try with 2 or 4 servos ?

 

 

 

[Brano]

@oracid i have 2 new geek servos behaviour is same with both servos.

[oracid]

Can you give the link of the shop where you bought the RX/TX ?

[Brano]

@oracid

https://a.aliexpress.com/_EHlSM2Z

 

[oracid]

This video looks very cool, but there is not much information on the pairing procedure between the transmitter and receiver.
Fortunately, this BIND procedure is described in 3 points near the bottom of the page of the link you sent.
I don't know this type of radio control, but I think that even if you have already done it, I invite you to start the BIND procedure again, scrupulously following the 3 points.

[Brano]

@oracid yes i tried it several times... Nothing work

[Ryokeen]

@Brano honestly at this point i think the transmitter/receiver is faulty. Also the ALI-express site seems to contain wrong information. The video you posted states that the transmitter uses AFHSD and not like on ALI FHSS. Also ali states that the receiver got a gyro in it and states there is an lcd display. Sooo kinda sus.
Anyways if it got a gyro in it, that can cause issues as some gyro systems not only correct the steering but also the throttle. And if the gyro is faulty, then yea.
I would suggest filling a complain on ALI and get a new set, i mean you swapped everything except the transmitter and receiver and checked the manuals. If it still doesn't work chances are high that those parts are faulty.

Else you could try out turning off the break function on the esc(the small soldered on lever), but i doubt that will fix anything

Edited January 13, 2024 by Ryokeen

[Brano]

@Ryokeen yes i tried break switch... No success.

I ordered brushless esc and also motor i will try this maybe it will work.  If not next step will be new rx/tx 😭 

 

[Krzychups]

Hello, 

I have tried to design a gearbox with bearings for an A2212 brushless motor. These are my beginnings with Autodesk Inventor. I have been having problems fitting the motor to the lego for a while. I have a motor from ZENE but want to do something with an old motor. 

It is possible to use a gear ratio of 12:36, 8:40 or 24:24, this is not the final version. I'll probably finish it when I go through a quick course on using the program (probably up to 2 weeks). You will also need a different shaft for the motor, as the pinion-shaft attachment is on the other side (look at the photo). I've made few mistakes - 100% infill (long print time, more weight) and I also need to redesign it because a lot of filament goes down to print the supports, I didn't dry the filament and I forgot to make the larger thread holes. 

20240120_121512 by Krzysztof Czech, on Flickr

a2212 gearbox 2 by Krzysztof Czech, on Flickr

a2212 gearbox 3 by Krzysztof Czech, on Flickr

a2212 gearbox 1 by Krzysztof Czech, on Flickr

I also redesigned the 5x7 frame with bearings. My first version was competently badly made.  Now it is much better.

20240111_181552 by Krzysztof Czech, on Flickr

5x7frame by Krzysztof Czech, on Flickr

As for the size of the bearings I can very easily change the size of the bearings if someone needs different holes. I'll try to make my parts out from nylon.

I'm curious what you guys think about these. Maybe something is badly done or do you have a different design idea?  More photos on my Flickr
Greetings

Edited January 21, 2024 by Krzychups

[Ryokeen]

Great job so far, especially the 5x7 frame.
For the A2212 motor mount, i'm not sure if 8:40 is needed or suited as the abs 8 thooth gears are not the strongest. Maybe that changed but i'm paranoid and try to avoid them or use metal ones :D
Else i like to have several gear ratio options .
But you might consider making that mount as closable parts. So that the gears are sealed from the outside. That way you prevent stones/sand getting in and also make it possible to have some lube in those gears without it flying around.