P1 SCARA Project

I have just started working on this SCARA robot and find it very interesting.

I have all the stepper motors working and now I'm trying to figure out how many steps make a degree of movement. This is all about the math or geometry.

So the reach of the SCARA arm is about 200mm so the process is to determine how many steps equals 90 degrees for both the arm and the elbow.

Once I have that I can use the law of cosines to position the arm any where on the grid.


2448 x 3264 - 2M


  • Nice platform. Did you 3d print the parts yourself?
  • I could have but it came as a kit with all the bearings and rods. Didn't want to mess with getting something wrong the first time. The belt on the arm is a little loose so they have an updated piece for that so I am printing that.

  • That looks fun.
    I hope you share a video once it's moving.
  • @Duane Degn,

    Careful what you ask for. I got the angles working so I can control the Shoulder and Elbow by setting the angle. Now I need to correct the Elbow because the Shoulder messes with the Elbow angle. Something is connected here.

    Here is a video with it in action using the Propeller Plug and Play board. SCARA on the move.

  • iseries wrote: »
    Here is a video with it in action

    Very cool. Thanks.

    I hope you keep adding videos as you make progress controlling it.

  • +1
  • My next issue was that because the pivot point where the Shoulder and Elbow are driven from cause the angle to change as the Shoulder moves I needed to correct for this in the Elbow.
    So if you request that the Elbow is 90 degrees from the Shoulder and the Shoulder is 90 degrees as well that you should end up with Elbow pointing straight up.

    Here is a video of the arm in action. You will note that because each stepper motor is in it's own cog they can all move together at once. Arm in Action

    3264 x 2448 - 2M
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