Introduction: How to Build a Simple Robotic Arm From Lego Mindstorms NXT?

Today, I will tell you how I built my robotic arm from Lego Mindstorms NXT.

In fact, I wanted to build a robotic tripod for my camera. I found out, that it's more difficult then it looks. After some experimenting I build this simple robotic arm.

I you want to build it too, you need:
- Lego Mindstorms NXT kit
- a computer
- time...?

There are only two rules you have to follow while building ANY robot:
1. rule: KISS (Keep it simple, stupid!);
2. rule: "The triple-F" rule a.k.a. FFF (Form following function!)

Step 1: Constructing the Base

The base is probably the simplest part of the robot to build. It's just a platform from the robot to stand on. You have to make sure, that it's long and wide enough. The center of gravity must be somewhere on top of the base, if possible, in the middle. Else wise, the robot will fall.

The base (in our case) are just a few beams that support the robot. More advanced robotic arms have motors in the base. These motors than move the arm, without moving themselves. Usually, the base has a motor that rotates the arm, but my arm rotates itself.

You can be much more creative with the construction of the robot then I was.

Step 2: Building the "rotation Module"

This is one of my rare robots that are built from modules. My robotic arm has three modules; one of them is the "rotation module".

It's very simple. It rotates the arm left and right and supports the other two modules. It's based on Matthias Paul Scholz's 90 degree join at:
http://mynxt.matthiaspaulscholz.eu/robots/motor90/index.html

Step 3: Building the "tilt Module"

The second module is the "tilt module". It's placed on the top of the "rotation module". Basically, we have a large gear (which doesn't turn) and a small gear which is driving around the big one. The gear ration is 1:10. That way, the arm can be more precise.

On top of this module there is a small platform, to which the claw is attached, but more about the claw later!

Attaching the two modules together couldn't be simpler. They are held together by a single shaft/axle, around which the "tilt module" spins. The arm can tilt for nearly 90 degrees, that's a lot!

Step 4: The Claw Module

This is the simplest of three modules. All it does is open and close the most basic kind of claws. This module is attached to the platform on the "tilt module".

I'm really sorry, but I'm afraid that I can't tell you much more about it. Pictures tell everything...

Step 5: Attaching the Sensors and Wiring

I used three sensors: light sensor, touch sensor and sound sensor.

The light sensor (Port 3) is located on the claw and lets the robot know, if the ball is there or not (and can recognize the "color" of the ball). The other two sensors are located on the platform of the "tilt module". Touch sensor (Port 1) serves as a sort of a button for me to press while the sound sensor (Port 2) measures the noise level (so I can give the robot commands with a clap for example).

At first, I wanted to include the US sensor as well, but I realized that it's relatively useless. You can still see it on one of the photos, but I removed it afterwards.

Now all that is left to do is the wiring. You must make sure that the wires do not disturb the movement and function in any way. You must also consider wire lengths for each sensor or motor.

Wiring (my robot):
- touch sensor -> Port 1
- sound sensor -> Port 2
- light sensor -> Port 3
- "rotation" motor -> Port A
- "tilt" motor -> Port B
- the claw -> Port C

Step 6: Attaching the NXT Brick

The NXT brick plays the vital role in Mindstorms NXT robotics, so you have to have it somewhere on the robot (or at least somewhere close). In my case only two brick hold together the NXT brick and the robot's base. It's very practical to have it on the base of the robot, 'cuz that makes the robot much more stable.

Step 7: Decoration and Finishing Touches

When you are pleased with how your robot works, you can put some effort into robot's looks. (Just remember the Triple-F rule!) I usually just put some of those odd orange bricks on the robot and that is usually that.
You can be much more creative...

Step 8: Programming

There are 5 programming languages you can use: NXT-G (default language), NXC (not exactly C), Robolab, Robotc, pbLua and NXJ. I used NXT-G (however I a bit tired of NXT-G and that's why I am trying to run away from Mindstorms...).

You are very free with your programming, that's why I won't talk about the programming any more.

Step 9: THE END

So, that's that! Here is a short video!


http://www.youtube.com/watch?v=VrfNUhzBoww

Comments

author
Legoawesome made it!(author)2015-06-03

nice

author
ChuC1 made it!(author)2015-02-26

Is there any part you can substitute for the curvy claw grabby things? I dont have any

author
muhammadfawadazim3 made it!(author)2014-10-30

Hello, how you all, i am working on a project that is a humanoid robot on lego mind storms nxt 2.0.i am doing coordinate based locomotion . can any body help me in developing the nxt 2.0 software program for the purpose, please.

author
gogoguy made it!(author)2014-08-07

That is very cool!!

author
SwaggerFul+Swellow made it!(author)2013-06-24

I'm so gonna build this! I plan on getting a NXT set in the next few months. So excited!

author
cerebender made it!(author)2013-03-02

Did you use an education set to build this? Because this can't be built with a 2.0 set without a ton of modifications or by trying to use some Technic parts. Also, the link you provided is now invalid, so there is no way to follow those instructions. It would help if you put a disclaimer at the beginning of the instructable to let people know this is old and not complete, and what kind of Mindstorms set is needed (or added-on parts) in order to build it. That way, no one will start building this and then realize they can't complete it (like I just did).

author
cerebender made it!(author)2013-03-02

Did you use an education set to build this? Because this can't be built with a 2.0 set without a ton of modifications or by trying to use some Technic parts. Also, the link you provided is now invalid, so there is no way to follow those instructions. It would help if you put a disclaimer at the beginning of the instructable to let people know this is old and not complete, and what kind of Mindstorms set is needed (or added-on parts) in order to build it. That way, no one will start building this and then realize they can't complete it (like I just did).

author
klarsen3 made it!(author)2011-07-10

where do you get that little thing that powers it and has the controls on it

author
GEORGE41708 made it!(author)2012-08-10

its the mindstorms ntx brick, its the "brain" for the whole robot, it comes with the nxt kit

author
FrodoandSam made it!(author)2012-06-01

I feel like this would probably be more fitting for the NXT Builder's Log, but it is definitely AAAWWWEEESSSOOOMMMEEE!!!

author
jwoo2023 made it!(author)2011-04-09

man! I have a NXT 2.0 not a 1.0
ㅠ_ㅠ

author
zmxninja made it!(author)2011-04-15

me 2 :(
u can still do just change programming

author
zmxninja made it!(author)2011-08-26

pretty simple to correct all u have to do is use the weird longshortturnlittlepiecethingymaajigy for claws if u gmd lol u probally wont understand what im sayig. just basically make a few subs for pieces

author
jwoo2023 made it!(author)2011-04-20

no its just that the parts used are different, sound sensor, gears, claws...
well not claws because we have the angle thing.

author
electro+centaur made it!(author)2011-08-09

There are no detailed instructions

author
the_burrito_master made it!(author)2008-07-11

I want the lego nxts *sob so bad *cry

author
TeacherOfTheWays made it!(author)2008-07-11

agreed *cry*

author
the_burrito_master made it!(author)2008-07-11

yeah... *sob*

author
118118 made it!(author)2008-08-15

me too *waaaah*

author
the_burrito_master made it!(author)2008-08-15

I'm still sobbing ;'(

author
hassannaeem101 made it!(author)2008-08-19

*cry* too expensive :(

author
the_burrito_master made it!(author)2008-08-20

yeah sob sob

author
dombeef made it!(author)2008-12-30

I have one

author
the_burrito_master made it!(author)2008-12-31

yeah every one but me seems to....

author
dombeef made it!(author)2008-12-31

lol

author
the_burrito_master made it!(author)2008-12-31

you shut up! jk, jk

author
dombeef made it!(author)2009-02-15

NEVER!!!!!!! lol

author
the_burrito_master made it!(author)2009-02-16

now you shut up!!!. jk again....

author
dombeef made it!(author)2009-02-22

what does JK meanbut, NO YOU SHUT UP! lol lol lol lol

author
the_burrito_master made it!(author)2009-02-25

JK means just kiddin'. SHUT THE POO UP ALREADY!!!!

author
dombeef made it!(author)2009-02-25

Naw....SHUT THE CRA~(lol) UP!

author
Jimmacle made it!(author)2010-12-02

Wow. You people post 5000 comments telling each other to shut up? RAISE MONEY AND BUY AN NXT (OR 2 LIKE ME) AND PLAY WITH IT!!! IF YOU NEED HELP JUST ASK ME! I mean it.

author
dombeef made it!(author)2010-12-06

I HAVE ONE!!! PLEASE DONT USE CAPS WITH EVERY WORD YOU USE!1!!
and i dont need hepl

author
Jimmacle made it!(author)2011-05-29

You definetely need some spelling help... Anyhow, I was ticked off from you two spamming the comments.

author
dombeef made it!(author)2011-05-29

Congratulations for replying to a 5 month old post. Even then, that was a while ago.

author
Jimmacle made it!(author)2011-05-30

Do I get a medal? :3 Anyway, I was off Instructables for a while.

author
444fox made it!(author)2010-05-29

STOP CRIING AND BY ONE

author
Mad+Cat made it!(author)2008-08-20

i have it ;)

author
looking4ideas made it!(author)2008-08-21

Im geting it

author
Koolraap made it!(author)2008-08-29

I've got two :P plus an rcx 2.0 :D

author
YummyPancakes made it!(author)2008-08-29

Ooh, beat me at the RCX! I have two NXT's as well, retail version. There are also a bunch of 'em at my school. Teacher lets us play with 'em every Thursday.

author
Koolraap made it!(author)2008-08-31

copycat ! our i used to be in a team that competed world wide, we placed 3rd in the Netherlands :D the worldwide competition is called first Lego league, ask your teachers if you may compete with a team at school, u might get lucky :D

author
YummyPancakes made it!(author)2008-09-12

That's actually what I was talking about. I've been doing it for the past year, actually. Last year's challenges were easy, this year's ones are HARD! Oh, and guess what our team name is.

author
YummyPancakes made it!(author)2008-09-12

Oh, err, sorry if I was straying off topic a little there.

author
looking4ideas made it!(author)2008-09-16

whats ur teams name? The Pancakes?

author
YummyPancakes made it!(author)2008-09-20

No -- lol, you're going to crack up at this -- It's The Flaming Fumachus (Mexican curly mustache style).

author
roksraka made it!(author)2008-09-21

guys! my instructable is not a forum!!!

author
looking4ideas made it!(author)2008-10-22

U rnt the boss of us! or RU?

author
Koolraap made it!(author)2008-10-22

who cares :P still fun around here

author
looking4ideas made it!(author)2008-10-23

People lets go for a record. The longest reply chain that stays on topic of the Instructable

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