12DOF-Q-3 Quadruped whith GeekServos

[oracid]

Here is a new video with a new quadruped.
Here, the goal is to offer a quadruped very easy to make, thanks to GeekServos which are Lego compatible while being RC servos with standard connections.

 

[grum64]

This is fascinating. It moves really nicely and is much more manoeuvrable than I thought it’d be. At the same time I can’t help feeling a little creeped out by it. All in all though I think it’s terrific.

[gyenesvi]

Very nice use of those servos, it really shows how far the limits of lego building could be pushed if the proper electronics were given in a more easy-to-use packaging.

[2GodBDGlory]

I've got a general GeekServo question to ask, and because there doesn't seem to be a dedicated topic for those, I guess I'll ask it here.

For a long time, I've been wanting to get myself a high-powered (11+V) electrical setup with proportional controls for Lego motors, but I don't want to spend lots of money on a Buwizz. What I do have, though, is a 3D-printed 3S Lithium battery box (3x 18650 cells) and a setup of parts originally from a mid-range RC car. My goal is to run Lego motors from the control circuit board of this car, powered by my 3S battery, which should be easy enough, but the servo has been my issue. I've got the servo that originally came with the RC car setup, but it's not really a convenient shape to use with Lego, so I've been wanting to figure out a better solution. GeekServo came to mind a while ago as an ideal solution, but the issue is that my circuit board has a five-wire connection to its servo, while GeekServos only run on three. I'm not very knowledgeable about how servos generally work with their wire setup, but I'm wondering if two of the five wires on my board can be ignored to run a GeekServo off of it.

Is this a question any of you are able to answer?

It'd be quite a nice solution for me if I could get it to work.

[oracid]

Thanks guys for your support.

Yes, @grum64, I understand your sentiment. Robots can be the worst and the best, but isn't our worst enemy most often ourselves.
@gyenesvi, Lego is an amazing medium for creativity, but it's just pieces of plastic. Why make it a dogma borrowed from religiosity?

I forbid myself nothing. I cut, I paste, I print and above all, I use everything that could easily increase my creative ambition.

[oracid]

Hi @2GodBDGlory. I'm not sure I can help you, but allow me a few remarks.
- Unfortunately, servos rarely work in 3S (11V). In your car, there is probably an electronic circuit that lowers the voltage to 5V.
- if your wires are colored, there is certainly a red wire and a black wire for the servo supply. You must connect these 2 wires to the red and black (brown) wires of your Geekservo.
- now, there are 3 wires left that you must successively connect to the orange wire of the Geekservo and test each time.

I hope this will help you a bit.

[Dave42]

HI @oracid, and others ;)

I´d just got one Seervo & 2 Motors from Greek, but i´m complete new to "normal" RC-stuff. Do you kown about a HP from Greek ? I´ve search the net, but i only find Sellers.

 

I´ve seen a Truck driving with the Greek stuff, and it runs about a 100 times better than sbrick or buwizz.

 

[gyenesvi]

44 minutes ago, Dave42 said:

I´d just got one Seervo & 2 Motors from Greek, but i´m complete new to "normal" RC-stuff.

What do you mean by Servo & 2 Motors? I have been wondering about these Geekservos, whether they can be used as regular motors, not only as (angular) servos, is that the case? It seems to me that some of the non-grey colored variants are 'continuous rotation servos', which I guess is synonymous to 'speed servos' (you can regulate the speed instead of angle), and would be good for driving cars? I could not find much info about it, only some aliexpress description which I don't really trust. Could that be something like speed servo mode in PU motors?

@2GodBDGlory, this link was recently posted in another thread about connecting Geekservos, it may be useful for you: https://dronebotworkshop.com/servo-motors-with-arduino/ . I'd also be really interested in putting together a minimal drive-steer system with LiPo batteries, control circuit and Geekservo motors.

[oracid]

There is the Grey GeekServo which is a real 360° servo that I have done a thread here, https://www.eurobricks.com/forum/index.php?/forums/topic/190129-geekservo-real-360°-programming/

And there is a Green GeekServo which is a continuous rotations servo, you can see an example here, https://www.eurobricks.com/forum/index.php?/forums/topic/191444-rolling-robot-chassis-ugv-to-start-in-robotics/

There is too a Red GeekServo which is not a servo but a DC motor.

 

[gyenesvi]

2 hours ago, oracid said:

There is the Grey GeekServo which is a real 360° servo that I have done a thread here, https://www.eurobricks.com/forum/index.php?/forums/topic/190129-geekservo-real-360°-programming/

And there is a Green GeekServo which is a continuous rotations servo, you can see an example here, https://www.eurobricks.com/forum/index.php?/forums/topic/191444-rolling-robot-chassis-ugv-to-start-in-robotics/

There is too a Red GeekServo which is not a servo but a DC motor.

 

Thanks for those links and the explanation, that sounds really interesting. So what's the practical difference between the Red end Green ones? Is it that the Green one allows more precise control due to the position sensor (like the PU vs PF L motor for example)? What's the advantage of the Red DC motor then? Is it more powerful? Different speed?

When searching for the the different colors (there's also a blue one), it seems to me that there are some gearing differences (speed / torque) among the continuous rotation ones (blue: 90 rpm, green: 160 rpm, red: 180 rpm), and the red also seems to exist in a regular and continuous servo version (all on aliexpress).

Also, it looks like these motors could be stacked onto one axle (techincally connected with a 2L axle), to form a bigger 3x6x5 motor from two 3x3x5 motors. Can you confirm that? Have you tried something like that?

Edited July 26, 2022 by gyenesvi

[grum64]

5 hours ago, oracid said:

I understand your sentiment. Robots can be the worst and the best, but isn't our worst enemy most often ourselves.

How right you are 👍🏻

[oracid]

The Green is a servo. That means that it has an internal electronic driver like any servo. It can be drived with an RC servo signal. So you can use it on a shield with the Servo Arduino library.
With value from 90° to 0°, it goes in a direction, and with value from 90° to 180°, it goes to the reverse direction. The speedest is 0° and 180°.
The Red and the Blue are DC motors with only 2 wires. They are not servos. The Blue has more torque but less speed than the Red.
You can't drive them like RC Servo. You can connect them to a Shield to a PWM pin to modify the speed, but you can't modify the direction.
If you want to, you need an external DC motor driver and  2 pins connection.
Hope this help you.

 

2 hours ago, gyenesvi said:

Also, it looks like these motors could be stacked onto one axle (techincally connected with a 2L axle), to form a bigger 3x6x5 motor from two 3x3x5 motors. Can you confirm that? Have you tried something like that?

I know nothing about this.

[gyenesvi]

Thanks for the info, that makes sense! I guess it will be best to buy some of these and start to experiment with them :)

6 hours ago, oracid said:

I know nothing about this.

The motors have axle holes on both sides right? So you should be able to put an axle into them into two ends. I believe you can put a 2L axle into one hole, and put another motor onto the other end of the 2L axle, this way coupling two motors, creating a bigger, stronger motor (of course you also want to connect them with pins). And the other axle hole on both motors will still be free to use as output. It makes sense to try that with the continuous rotation motors (though it could also be useful with the angular servo to have a really strong servo). I hope this works, as it seems to have great potential.

[oracid]

13 minutes ago, gyenesvi said:

I hope this works, as it seems to have great potential.

It's possible with 2 motors, even 2 Lego motors, I've done it before, but with 2 servos (angular or continuous rotation), I think it would be more complicated. No two servos react exactly the same. There could be opposing stresses that would accumulate and in the end destroy the 2 servos.
But it would be interesting to test this, indeed. I will do that, one day. Good idea !

 

[2GodBDGlory]

17 hours ago, oracid said:

Hi @2GodBDGlory. I'm not sure I can help you, but allow me a few remarks.
- Unfortunately, servos rarely work in 3S (11V). In your car, there is probably an electronic circuit that lowers the voltage to 5V.
- if your wires are colored, there is certainly a red wire and a black wire for the servo supply. You must connect these 2 wires to the red and black (brown) wires of your Geekservo.
- now, there are 3 wires left that you must successively connect to the orange wire of the Geekservo and test each time.

I hope this will help you a bit.

Thanks for the help; that's probably about the best I'm going to get anywhere, given that the five-pin servo seems to be only used in proprietary designs.

You're right about the servo running on only 5V; maybe I should have mentioned that.

Yeah, I do have those red and black wires, so that would be a good start.

Being rather cheap, I don't really want to buy one and then find out that it doesn't work, but luckily, I'm heading to a buddy's house this weekend, who has a standard three-pin servo for an Arduino. If he's fine with it, I'll plan on testing my controller with that standard servo, and assume that results with a GeekServo would match it.

 

15 hours ago, gyenesvi said:

What do you mean by Servo & 2 Motors? I have been wondering about these Geekservos, whether they can be used as regular motors, not only as (angular) servos, is that the case? It seems to me that some of the non-grey colored variants are 'continuous rotation servos', which I guess is synonymous to 'speed servos' (you can regulate the speed instead of angle), and would be good for driving cars? I could not find much info about it, only some aliexpress description which I don't really trust. Could that be something like speed servo mode in PU motors?

@2GodBDGlory, this link was recently posted in another thread about connecting Geekservos, it may be useful for you: https://dronebotworkshop.com/servo-motors-with-arduino/ . I'd also be really interested in putting together a minimal drive-steer system with LiPo batteries, control circuit and Geekservo motors.

Ok, thanks! I'll take a look at that link. It might get too technical for me, though!

[EDIT] It didn't get too technical, and was definitely worth reading to expand my general electrical knowledge! I'm not sure whether it'll directly help me with this problem, but I don't know yet.

Edited July 26, 2022 by 2GodBDGlory

[glowytheglowbug]

absolutely love your builds i might try something like that thanks for the code!