Asked — Edited

A Circle Script?

Hello there!

I have 2 servos: One for X axis and another for Y axis.

I am trying to build a script that will make the arm move in a perfect circle form, but having trouble with transforming a circle formula into the EZ script syntax.

Can you please help me?

Thanks, Roi


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I've been running this through my head and I'm not sure you can create a perfect circle with two servos and EZ-Script. It would look more like a diamond. Someone with more experience can correct me on this, but I believe you can only move one servo at a time.

Your problem made me think of the old Etch A Sketch toy. Drawing a circle on the Etch A Sketch was nearly impossible without moving both wheels at the same time.

You could get close, though. I think you need a script that increments each servo by one step, then switches the direction based on the apex of each quadrant. A simple idea on this would be to tell the servos: Up, Left, Up, Left, Up, Left, Up, Up, Right, Up, Right, Up, Right, Up, Right, Up, Right, Right, Down, Right, Down, etc. You'd have to work out the pattern, but that's the gist of it.

You could use parameters to gauge when to switch the direction of the servo. I'd think you'd need two parameters for servo direction (one for X, the other for Y) and a parameter to count the completed steps in each quadrant. Then you'd probably have four code loops. The first loop would run for a certain number of steps, reset the count parameter and update one of the direction parameters, then it would go to the next loop. The second and third loop would do the same. The fourth loop would just stop after the final step is counted.

I really wish I had an Etch A Sketch to attach two servos to so I could help test this with you. Its late, so my brain is turning to mush. I'll try to put a sample code together in the next day or so, if my rambling isn't clear enough. :)


Thanks Mc, Will be waiting to see what you come up with.

Wouldn't using a circles formula (with Sqrt and Power functions and loops and all) + using the Round function, get us closer to a sort of pixelated circle, rather than a diamond shape?

United Kingdom

I don't have time at the moment to do much but maybe this website could be of some use to you...


I assume you are using a standard pan/tilt bracket for a shoulder joint?


Try this...


# This is the starting degree (must be less than end degree)
$degStart = 0

# This is the ending degrees (must be greater than start degree)
$degEnd = 360

# This is the circle diameter
$diameter = 20


$deg = ($degStart / (180 / $pi))

$xPos = 50 + (Cos($deg) * $diameter)
$xPos = Round($xPos, 0)

$yPos = 50 + (Sin($deg) * $diameter)
$yPos = Round($yPos, 0)

Servo(d0, $xPos)
Servo(d1, $yPos)


IF ($degStart = $degEnd)



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Thanks a lot for all these great responses and for the script!