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Picture of Circle Drawing Machine

This is a basic drawing machine that creates circles. It is based on a ruler and a 3D printed marker slider. The machine pulls the marker around a weighted center pivot to create a circle. By repositioning the marker along the length of the ruler you can draw circles of different sizes.

This was created to help support a 5th grade curriculum, but surely can be used at other grade levels. See the attached lesson plan for how you might use it in the classroom to explore measurement.

If you are looking for a machine for older students that demonstrates more complex mathematical and engineering principles, check out the Torus Drawing Machine.

Step 1: Materials

Picture of Materials

(x1) Continuous rotation servo (modified for direct drive)***
(x1) 12" Ruler
(x1) 3D Printed Marker Bracket
(x1) 3D Printed Wheel Hub (not pictured)
(x1) 3XAA Battery Holder
(x3) AA Batteries (not pictured)
(x1) Sharpie marker (not pictured)
(x1) 76mm Skate wheel
(x1) 3/8-16 x 3" Bolt
(x1) 3/8-16 Nut
(x20) 3/8" x 2" Fender Washer
(x1) 5.5mm male screw terminal power plug
(x1) 5.5mm female screw terminal power socket
(x4) Rubber adhesive feet
(x2) Self-adhesive zip tie mounts
(x3) 8" Zip ties
(x2) 4" Zip ties
(x1) Large sheet of paper (at least 12" square)

*** See Step 3 for more details about modifying a servo.

samayaraj13 days ago
Is it that hard to make a circles?
randofo (author)  samayaraj6 days ago
Seems like a waste of time and limited resources to make something complicated when a yardstick, a pin, and a sharpie would have worked just as well. And would have also been a teaching tool. A machine to draw a circle. LOL
chris.decke14 days ago
This instruction is with no doubt highly detailed, and the attention to detail is perfect. All instructions a clean, clear and laid out piece by piece . Videos are popular at the moment and I would suggest make a video if you already haven't. Well Done.