Testing Teaching Pendant - Dancing Robot

We are working to create a teaching pendant for the LittleArm 3D printed robot. While we were doing some tests music was playing so we rolled with it. Enjoy

We Just Launched on Kickstarter

We have been working to turn the 3D printed robot into a kit. We are almost there.

We have launched a Kickstarter to get the funds needed to start producing the LittleArm in greater quantity. Please check out the LittleArm Campaign and be one of the first to get the kit.

But of course always feel free to download the parts and code to make your own.

Installing and Running Python on Windows

For those that use Windows.

In order to run the python programs on this website for the LittleArm (3D Printed Robot Arm) you will need Python installed. And if you want to use it from the command line you will need to add it to your environmental variables

Here is a tutorial on how to install Python and then run it from the command line. 

For those that do not like to read, here is a video of the process.

Instead of running our programs from the command line, you may also simple start up Python IDLE and then open and run the python programs from this website. That is a more intuitive and graphical method.

Here is our own video on installing python and running the programs in IDLE

Tutorial: Training the Robot Arm using the Python Gui

We have had the capability to train the robot for a while now. Here is the code used in this tutorial.

The interface is already pretty intuitive, but some of the application may not be clear. Soon we will make a video of how to launch the GUI and get it working on windows.

In the meantime have fun training the robot. And please share what you make it do on the forum

There are two tutorials, the long version and the short. Use the one you need.

Long Version

Short Version

Demo: Most Useless Machine

We are working on putting together a bunch of demos for tutorials and videos. This is one of the first. It is our take of the "World's Most Useless Machine."

We used the training function to get the motion down. In the future we may create an Vision system that can detect objects that the robot can just move.

Graphical Arduino Programming

Hey Everyone,

We have built a decent foundation of code for everyone to start making some cool programs. But that code is still standard computer code (C and Python). We would like to make easier for those who are new to programming to work with the 3D Printed Arm.

Here is a Block-Based Graphical Arduino Programmer, Blockly, and it is online so you can use it anywhere to program Arduino. We will create a tutorial very soon of how to program a set of sequences with this program.

We will also convert several of our basic Arduino Programs to Blockly as soon as we can. And we are working on getting a web interface up so that you don't have to go through the hassle of setting up python on your computer.

Another alternative to Blockly is BitBloq


Parallel Execution of Joint Motions

Normally when you make a robot, you don't want it to move one joint at a time. Usually you want something more fluid where several joints are moving in tandem.

While it is impossible to have parallel execution on the arduino, the illusion of parallel execution can be achieved.

It is done by moving each joint only a few degrees and then moving the next joint a few degrees. Since the delays between the movements are milliseconds it appears as if all the joints are moving at once.

This code was tested using the Training Program created in the last post.  The user control the arm to some position they want it to be at and then records that position. Then when there are several positions the arm will move directly to each point.

For those familiar with engineering, what we have created is a very basic PD controller.

What is great about this parallel movement is that while before when we did training we may have had to record single joint movements to ensure that the arm didn't collide with the table. Now that is not as much of a worry since all the joints can move to their desired positions simultaneously.

Code for this post for Parallel Joint Movement

//Primary Function for Simultaneous Servo Motion
int servoParallelControl (int thePos, Servo theServo ){
    int startPos = theServo.read();        //read the current pos
    int newPos = startPos;
    int theSpeed = 9;
    //define where the pos is with respect to the command
    // if the current position is less that the actual move up
    if (startPos < (thePos-5)){
       newPos = newPos + 1;
       return 0;
   else if (newPos > (thePos + 5)){
      newPos = newPos - 1;
      return 0;
    else {
        return 1;

Training the Robot: Record a Motion Sequence and Play It Back

Record Sequence and Playback Code

A robot is not very useful unless a person can work with it easily. While it is not difficult to put in commands for where the servos should be positioned, it is much easier if you can direct a robot to where it needs to be and have it remember that action.

That is what this program is for. Using the GUI one can move the 3D printed robot arm through a series of motions, recording each step, and then have the robot repeat the seqence. It is a great piece of software for just creating quick demos. Or for kids to learn how programming works sequentially.

The next step will be to modify to the arduino code so that is changes all of the servo positions seemingly simultaneously. Right now it moved the shoulder then the elbow. This is a little slow and un-elegant. The next iteration will have them all moving at once.

See the video below to watch how to train the robot.

Demo: Pick and Place

Here is a very simple example of using the servo control function that was created early just to have the robot perform a set of preprogrammed tasks.

In order to get the positions I used the gui program to take it through the sequence. I recorded the positions and then entered the sequence into the arduino code.

In the future I will add a recording feature to the python code so that the user can use the gui to move the arm through positions and then just have it repeat the motions automatically.

Here is the Pick and Place code

For any other resources visit the Project Links Page

If you don't want the file you can copy and paste the code below

#include <Servo.h>  //arduino library
#include <math.h>   //standard c library

#define PI 3.141

Wiring Diagram: Arduino 3DOF Arm

Here is a basic wiring diagram for the 3DOF arduino robot arm. All the parts for the diagram can be found on the Project Links Page