Asked — Edited

I Want To Make Jd Longer Out Of 5 Servos Instead Of 2

Hello, I want to make JD's legs and arms with 3 or 4 servo each. Has any one try making JD with Longer arms and legs, I'm wondering also how JD will move with more servos ? Please HELP Thank you.


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I am so confused by this post, but I think that you are asking how you would make the wires longer on the servo motors?

There are extenders in the store for this. From the question and how it is asked, I am not going to recommend that you make cables. I would buy the extenders.


Thank you so much I appreciate it :)


Note: these extender cables are commonly available at any hobby store that services the R/C community. If you are ordering items from EZ-robot anyway, then add them to your order, but the tracked shipping from EZ-Robot is too expensive for a $2 commonly available part. You aren't taking money out of EZ-robot's pocket by doing that. They sell these kinds of parts as a convenience to their customers, not as a profit item.



Has anyone actually made their JD taller and walking gaits function successfully / correctly ?


These thoughts went through my head also, but I decided that trial and error is the mother of learning and decided that I would just answer the question as I interpreted it.

I seriously doubt that what he is trying to do will work. servos have a certain strength and the further you get from the servo, the higher the strength that is needed. When you add in the weight of the servos along with the distance that the servos are from one another, I am pretty sure that you would ultimately come to the point that the robot wouldn't be able to move its upper servo, and thus not be able to move its leg forward or backward. He may have some design that he isn't sharing but I suspect that he will run into issues.


I'm trying the same thing, my plans include 5 servos per leg (foot, ankle, knee, thigh and hip) and 4 for each arm. Also a pan and tilt for the head and thinking of including the same for waist. But, legs first, then arms. Just need get the cash flow to buy servos.


oh okay :) how is it going so far


I would add the 4in1 sensor so that you can have some scripts running to detect if it is falling over and move to a known stable position or stand back up.



Hello, Instead of using Jd, I used some of the .stl files from "Poppy". I found them to be light and strong. I installed regular servos in place of the Dynamixel servos normally used. I only moved the arms and shoulders and I also had 2 waist servos. It kind of worked but I found the servos to be weak. The spine was not real rigid, but it could hold itself up. (Waist, shoulders, arms and neck) The whole assembly really needed a lot of torque. I don't think you could ever make the whole thing really stand or walk.

Poppy was made for poses, not real standing and movement. I may go back to it to see if I can do more with arm and torso movement someday. Maybe legs too.

If you want the servo conversion tray info and on how I made the pivots let me know. I will dig around and see if I can locate pictures and .stl files

Ron R


@Everyone... Guys, seromo is just a kid remember.... albeit a really smart kid:) You should tailor your responses accordingly...



The key to JD and EZ robots in general, is the ability to modify and try things. You have an idea which should be tried. My advice is to realize that JD has a certain amount of power in the servos. Also his balance is maintained by big feet.

I think you should build his legs first but consider his feet may need to have light weight shoes to help maintain balance. You could remove the arms for now and use those servos for tests. later you may need arms to help maintain balance.

The Auto Position panel can give you the ability to set movement. Making small movements at a time will allow you to see if he can walk the way you want.

Try making it work and post your progress.

Ron R


Just a thought, if you have the ez bit blocks, you may need to try to widen Jd's hips to get a better stance.

But, Remember, a lot of additional weight is not good.