RE: Put one of these on your bot

I’m going to try and do this post up right. And explain everything better than what I have been doing. This is in RE to put one of these on your bot. I couldn’t help but try to make it out of all vex stuff just as soon as I saw that first post. Now I remember back in the day that radio shack had a robotic arm that my brother and I used to play with all the time. That was sometime in the mid to late 80’s. It was a game, so little orange balls were included as well as some tubes to put the balls in, and some boxes to stack them up with. It was a truly awesome toy to play with. So thanks for that post. Now it’s not complete and I’m thinking that I won’t finish this particular one due to some of the problems I’m running into. But version 2 is already in the works with the disassembly of V1.0. Now I’m going to show the different aspects of it and also tell about what is going to be different in V2.0.


This is where the shoulder will be joined to the bot and its controller. I decided that this should be done for freedom of movement. If I had placed the controller on the base then I would have wires twisting up and tangling and well pathing would be harder as well. So this arm got a chest to host its brains. This can be seen in the pictures that accompany this post. Now I wanted the arm to have 360 ‘ motion so I bolted a gear to some standoffs and placed a motor and 12 tooth gear to travel the torso around the stationary gear. To me that is the best part the freedom of motion.

Going to square out the chest a bit more and redo the main structure support columns.


I picked a corner of the torso that had the least of the electronics in it. And started on my gear box I knew the arm was going to be heavy so I tried for a high torque rating. Using the 1x25 flats I started to build the first ‘bone’. The elbow is at the end of it. There is not much more about it.

Well this is a problem. First the gear box will be changed to a higher torque ratio 

than what it already is. 12 inch long steel is heavy especially when you’re supporting it at the edge. So the changes will be from steel to aluminum standoffs. Much lighter and I feel it might be a bit more versatile. I’m looking at making a different type of joint all together similar to that of a servo bi-ped.


Well this joint is a bit difficult with space so some of the gearing was placed on the outside of the arm.

The arm needs to be wider than the ½” that it is. I’m also looking into rebuilding the supports like in the shoulder.


Now this joint was the most difficult to design and work. It flexes both up and down as well as rotates 180 ‘. I figured that there would not be so much weight lifting on the wrist area so I left out the gear ratios and went straight to the motor / servo. And it’s going to need a claw upon I have not decided how it should grasp and what type of movement it will require.

This is going to be a bit tough because it’s almost as simple as I feel that I can make it with the vex parts. I might get frisky and bend some more parts which I would hate to do. Will add final gripper assembly.


The base is a bit unstable. For starters the chest rises up 3 inches from the base which it only needs to be an inch max. Then, there is the fact that the steel supports are not placed properly nor are they bolted down sufficiently had plans on placing tank treads upon it but with all the instability this bot is having I didn’t think that would be a wise decision even though there were outriggers in the plan. I don’t have any pictures of my out riggers which I will need to do so everyone can get an idea on how they can possibly help stabilize their bots when they are no longer traveling. Lets not forget that movement will be controlled by a secondary vex controller which will be controlled by another indivual.


Well for starters the tank tracks will be installed then from that I can work on securing the base plate for the torso and setting up the outriggers. Modify my transmitter so that I have 2 toggle switches on the upper 2 corners that can be flipped to change my frequency so that one controller has 4 frequency’s and is able to control 4 processors. But that’s going to be a bit in the future. I want to learn a bit more how this all is set up. I might even be able to use a different crystal type.


This has been one of the most challenging bots I have built though in the first few hours I had all but the elbow and wrist completed. I suppose that is the reason for my lack of support structures. Building this bot has also opened up my imagination. What possibilities could come of this. Well take off the wrist and put a bucket and you got a back hoe. It has generated so many ideas that I might not want to build V2.0 but instead one of my other ideas. I would really like to implement the screw slide into one of my bots and I feel the arm bot could almost do this with an extending reach. But that is more research and development. I can’t wait till this outage is over and I get December off I don’t think I will ever leave my workshop.

Base and supports

Movement joints

Palm controls and movement

Wow This Is A M A Z I N G!!

first of all, i found a flaw that might brake it. the counter weight cant be to heavy or it will topple over backwards, and second of all, the arm looks a bit to long for the counter weight to handle. is that why there is someone in a picture holding it down? just asking!!!:smiley: :smiley:

I know just the solution:)
you have an arm in the counterweight section, and have that adjust the weight property’s on the x, and y axis’s or

_______ -this arm is down(least counterweight):o

_______ __ -This arm is horizontal(most counterweight):rolleyes:(boom)


_______ | -this arm is up(least counterweight)

:confused: ??? you ask (beats me I just suggested it!!)

or you could just put a chain and hull the counterweight over to adjust!!:cool:

dang i knew i forgot something to talk about in my description. will post more on why someone was holding it and why the counter weight was the way it was.

That looks like some good work so far! :slight_smile:

In the future, it may be easier if you directly Upload your images to the Gallery here on on the Forums, especially if you have a lot of pictures. :wink:

wow thats kool how it has a wrist and stuff are you going to ad a hand so it canj grap things?

yeah, that look sweet!! :open_mouth:

do you think you could make a video? i would like to be able to see something like that in motion.

first my internet got taken away at work. so no more mid day posting. alas the counter weight system was a series of gross miscalculations. V2.0 will have a much better counter weight system but i’m not so sure that i will be able to make it adjustable but that will be ok. and the reason there was someone holding it was behind the platform it was resting on was a 8 foot drop and thats something that i didn’t want to fall and kill my cat. it is pretty stable there are a few instability issues floating with it but for the most part when it was resting on flat level surface i could fully extend and swing it 360’ but any way it looks like i’m going to need to invest in a video camera. thanks alot for the support…torn between the robotic arm and a screw actuator bot … flips a coin

I was planning on using hydralics (double acting) when christmas comes to make a long arm :slight_smile:

WOW!!! ok so i got motivated this evening and totally redid the whole base. now for the cool part.

V2.0 Base
Installed Tracks and increased the width of the base nearly 7 inches. Lowered the stationary gear to get a better C.O.G. (center of gravity). While doing so I worked on a few of other thoughts that poped into my head while at work. Now I want swivel tracks that piviot independant one another. So with that in mind I set out to match up some springs. I have like 5 or 6 kits of various spring sizes… never know when you will need one. Anyway, So I got thisbright idea about dampers and well it’s not the greatest idea, but it works, just not for a 6lb arm. I reattached the now unproportional arm and the bot didn’t even wiggle anymore. so here is the new pics of the base.