Stepper Motor Drawing Machine

Drawing machine using stepper motors and an Arduino controller.
Sketch for Arduino Uno listed below:
/*
free running pulse train generated on outputs 3,6, and 7
based on countdown of redcount, yelcount, and grncount.
*/
int yellow=6;
int red=7;
int green=3;
int redcount=125; // turntable
int yelcount=29; // yellow motor
int grncount=25; // green motor
int redvar=redcount;
int yelvar=yelcount;
int grnvar=grncount;
// the setup function runs once when you press reset or power the board
void setup() {
// initialize three digital pins as outputs
pinMode(yellow, OUTPUT);
pinMode(red, OUTPUT);
pinMode(green, OUTPUT);
pinMode(13, OUTPUT); //
digitalWrite(13,LOW); // turn off onboard LED
}
// the loop function runs over and over again forever
void loop() {
--redvar; // reduce redvar by one
if (redvar != 0) {goto redskip;} // skip motor pulse if redvar is not 0
digitalWrite(red,HIGH); // Step Red on
delay(1);
digitalWrite(red,LOW); // Step red off
redvar=redcount; // reset redvar
redskip:
--yelvar; // reduce yelvar by one
if (yelvar != 0) {goto yelskip;} // skip motor pulse if yelvar is not 0
digitalWrite(yellow,HIGH); // Step yellow on
delay(1);
digitalWrite(yellow,LOW); // Step yellow off
yelvar=yelcount; // reset yelvar
yelskip:
--grnvar; // reduce grnvar by one
if (grnvar != 0) {goto grnskip;} // skip motor pulse if grnvar is not 0
digitalWrite(green,HIGH); // Step Green on
delay(1);
digitalWrite(green,LOW); // Step green off
grnvar=grncount; // reset grnvar
grnskip:
delay(1);
}
---------------------------------------
Parts List
From Amazon
Arduino or Elegoo Uno R3 Controller Board $17
DRV8825 Stepper Motor Driver and Shield Boards (3 ea) $19
Nema 17 Stepper Motors (3 ea) $28
Lazy Susan Turntable Ring, 8”, TROOPS BBQ $18
Flange Shaft Coupling 5 mm (4 ea) $9
12 V 2A DC Switching Power Supply $8
Stabilo Point 88 Fine liner pens $12
Cardstock paper $13
From Home Depot
Aluminum Rod ¼” (2 ea) $11
Hinge $2
10-32 x 3” bolts and nuts for legs (4 ea) $5
Spare Parts in my shop
Aluminum T-Track for ¼”-20 T bolt or Hex head bolt
Ball Bearings
Hex Bolts and Wingnuts, ¼”-20
PVC Blocks
Set Screws 6-32
2x4 wood blocks
¾” pine shelving
Prototype Board
LEDs (3 ea)
270 Ohm Resistors (3 ea)

[@rusticagenerica]

Damn beautiful bearing system you have there.

[@beatrute2677]

nice, i use to love making spirographs when i was a dwarf

[@weirdsciencetv4999]

This is genius. I love it! Subscribed!!

[@MAS150MD200]

Awesome.

[@weirdsciencetv4999]

Have you considered programming some kinematics and making this an arbitrary shape drawing machine?

[@jeffg8232]

Oh, my goodness, this machine is arbitrary enough. Even small changes to the arm length or radius can make huge differences in the pattern. I often don't know if a good pattern is being drawn until it's almost finished. Even the starting position or phase of the two arm motors can make a difference. Sometimes it turns out a mess. I've learned to keep elaborate patterns from crossing the center of the table. That can generate a messy bulls-eye blob. I've shown examples of my good patterns. I've made lots of bad ones as well.
There are many kinematic drawing machines on RUclips using pendulums. Some are very clever and interesting. Check them out. Thank you for your comment.

[@weirdsciencetv4999]

@@jeffg8232 Yes, I have seen lots of kinematic drawing machines too. Just saying your kinematics as they are might already be capable of that, just with some code additions. It was just a question if you intended to do that personally, which the answer of course is ‘no’.

[@jozefnovak7750]

Super!

[@rusticagenerica]

You like PVC blocks :))

[@BrianBoniMakes]

Have you seen a Rose Engine also called a ornamental turning lathe or Guilloche? They are mostly known for making the patterns on the faces of expensive watches. Your drawing machine reminds me of these. It looks like you have no way to "preview" your program. As far as spirograph goes your examples look better than any plastic gear videos I've seen, Was this your idea? Well done!

[@jeffg8232]

I'll look up the ornamental lathe. I'm always interested in tools like that. My inspiration was the old Hootnanny toy I had as a kid, but I copied many elements from the Drawing Machine II by Photonflood on RUclips. His design has variable control of all 3 motors. I just made everything direct drive, and employed the Arduino as a controller. I also made it much smaller. You are correct that there is no preview. It's all trial and error. I make notes on my speeds and arm settings, and then make small adjustment to try to improve things. I've learned to not let the pen draw across the center of the page. After multiple passes across the center, it turns into an inky blob. Thanks for your comment.

[@rusticagenerica]

Dear God, the system looks complex :)