For the last few months, my polargraph has been a perfect companion during the long hours I've been chained to my workstation. It would pleasantly grumble its way all day, providing just enough distraction to keep me from going nuts from the monotony of work. My wife even commented that there was something relaxing about the sound of it, and since she frequently works about 10 feet away from me, it was important that it didn't bother her.

Then something awful happened.

I started experimenting with Rasterbator and StippleGen.

Since then, the nearly constant sound of whining servo gears has been increasingly getting on my nerves. 10,000 PenUp commands and 10,000 penDown commands for one drawing, 6,000 for the next....grind...grind....grind.

On top of that, Sandy even added "cleverer pixel skipping routines" (yes, I'm the one who requested it), adding more pen lifts for "normal" polargraph drawings, too.

I googled "quiet servos", shopped around, read the postings of various forums, and considered greasing the gears. Then the obvious occurred to me.

I opened the arduino sketch and found the lines that contain the settings for the servo commands:

// Pen raising servo
Servo penHeight;
int const UP_POSITION = 180;
int const DOWN_POSITION = 90;
int const PEN_HEIGHT_SERVO_PIN = 10;
boolean isPenUp = true;

I knew my servo didn't need to rotate that much to lift my pen off the paper, and didn't have to go all the way back to 90 for the pen to touch the paper. After some trial and error, I settled on:

int const UP_POSITION = 130;
int const DOWN_POSITION = 105;

That's quite a difference -- 25 degrees versus 90. Now my pen lifts are a very brief "psst" sound.

My machine just finished a 20 hour drawing, and the cute little "psst" sounds rarely drew my attention.

There was problem I don't understand, however. It seemed the pen was landing with more force than before, sometimes with an audible "thunk" sound followed by a gondola wobble. Perhaps I just never noticed it before? Even so, I'll take that and the slight damage it does to the pen tip over that...that sound.

Since the *thunk* sound doesn't happen every time, I'm now wondering if it happens because of the herky jerky way servos sometimes start their movement. Now that the servo horn is moving only 25 degrees, that might be within the "jerk zone".

SKILLS.