Levitation, a 3D Printed Automaton Illusion

I feel truly blessed each and every time family, friends and/or followers send me links to videos of automata and challenge me to recreate the mechanisms involved. "Levitation, A 3D Printed Automaton Illusion" is one of those challenges, this one recreating the mechanisms behind "Laetitia Princess of the Air" by Pierre Mayer, a "levitation" illusion. I have no knowledge of how Mr. Mayer created his illusion, but my implementation of the mechanism seems to adequately duplicate his illusion using the classic "mirror(s) and string(s)" technique (albeit using an acrylic mirror for safety) as our grandkids thoroughly enjoyed it, and Lora and I hope you and yours do as well!

As usual I probably forgot a file or two or who knows what else, so if you have any questions, please do not hesitate to ask as I do make plenty of mistakes.

Designed using Autodesk Fusion 360, sliced using Ultimaker Cura 4.6.1, and 3D printed in PLA on an Ultimaker 3 Extended and an Ultimaker S5.

Supplies:

• Thick cyanoacrylate glue.
• Black polyester thread.
• Double sided tape.
• AWG28 Stranded Wire (green, blue, yellow, red and black).
• Soldering iron and solder.

Step 1: Parts.

I acquired the following parts:

• One reed switch (2 by 12mm, Gikfun 20pcs Reed Switch Normally Open N/O Magnetic Induction Switch Electromagnetic for Arduino (Pack of 20pcs) EK1621x2, on line).
• Four 3MM diameter by 1.5MM thick neodymium magnets (local hobby shop).
• One N2 style 35RPM 6VDC gear motor (on line).
• Two salvaged tea lamp LEDs and flames.(https://www.amazon.com/gp/product/B00T28FWVS/ref=ppx_yo_dt_b_asin_image_o00_s00?ie=UTF8&psc=1).
• One AAA dual battery holder with switch (on line).
• One sheet of mirrored acrylic (https://www.amazon.com/gp/product/B086W99Q55/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1).
• Two AAA batteries (my battery stash).
• 6" polyester thread (my wife's sewing kit, but don't tell her!).

I 3D printed the following parts at 20% infill:

• One "Adapter, Candle.stl" (.15mm layer height).
• One "Arm, Left.stl" (.06mm layer height).
• One "Arm, Right.stl" (.06mm layer height).
• One "Axle, Arms.stl" (.15mm layer height).
• One "Axle, Cam.stl" (.15mm layer height).
• One "Axle, Geneva, Driven.stl" (.15mm layer height).
• One "Base, Cover.stl" (.15mm layer height).
• One "Base.stl" (.15mm layer height).
• One "Body, Shoulder.stl" (.06mm layer height).
• One "Body.stl" (.06mm layer height).
• Two "Bolt, Frame.stl" (.15mm layer height).
• Seven "Bolt.stl" (.15mm layer height).
• One "Cam, Axle, Arms.stl" (.15mm layer height).
• One "Cam.stl" (.15mm layer height).
• Two "Candle Tower.stl" (.06mm layer height).
• One "Frame, Front.stl" (.15mm layer height).
• One "Frame, Rear.stl" (.15mm layer height).
• One "Gear, Motor.stl" (.15mm layer height).
• One "Geneva, Drive.stl" (.15mm layer height).
• One "Geneva, Driven.stl" (.15mm layer height).
• Two "Hand.stl" (.06mm layer height).
• One "Head.3mf" (.06mm layer height).
• One "Mirror.stl" (.15mm layer height).
• One "Mount, Body.stl" (.15mm layer height).
• Two "Panel, Long.stl" (.15mm layer height).
• Two "Panel, Short.stl" (.15mm layer height).
• One "Stage.stl" (.15mm layer height).
• One "Yoke.stl" (.15mm layer height).

This mechanism is a high precision print and assembly using at times very small precision 3D printed parts in confined spaces with highly precise alignment. I printed the parts using the Ultimaker Cura 4.6.1 "Engineering Profile" on my Ultimaker S5, which provides a highly accurate tolerance requiring minimal if any trimming, filing, drilling or sanding. However, prior to assembly, I still test fitted and trimmed, filed, drilled, sanded, etc. all parts as necessary for smooth movement of moving surfaces, and tight fit for non moving surfaces. Depending on your slicer, printer, printer settings and the colors you chose, more or less trimming, filing, drilling and/or sanding may be required to successfully recreate this model.

I carefully filed all edges that contacted the build plate to make absolutely certain that all build plate "ooze" is removed and that all edges are smooth using small jewelers files and plenty of patience to perform this step.

This mechanism also uses threaded assembly, so I used a tap and die set (6mm by 1, 8mm by 1.25) if required for thread cleaning.

Step 2: Base Assembly.

For base assembly, I:

• Pressed the gear motor into the gear motor mount hole in "Base.stl".
• Pressed two of the magnets into the base assembly magnet mount holes.
• Pressed the remaining two magnets into "Geneva, Driven.stl" such that the magnetic polarity matched that of the magnets in the base assembly.
• Threaded "Axle, Cam.stl" into "Cam.stl".
• Positioned the cam assembly as shown then snapped "Yoke.stl" into the tracks in the base assembly and around the pin on the cam.
• Threaded "Geneva, Drive.stl" onto the cam axle such that when the pin on the cam was fully down, the pin on geneva drive was fully right, then secured the axle to the cam and geneva drive with small dots of cyanoacrylate glue.
• Bent one end of the reed switch as shown.
• Slid the reed switch into the base assembly (the final position will be set later).
• Pressed "Gear, Motor.stl" onto the motor output shaft.
• Soldered a red wire to the motor "+" terminal.
• Soldered a black wire to the motor "-" terminal.
• Soldered green wires to each end of the reed switch, then secured the wires to the base assembly using small dots of cyanoacrylate glue.
• Attached the battery holder to the base assembly using double sided tape, running the battery holder wires as shown.

Step 3: Top Cover Assembly.

For top cover assembly, I:

• Attached "Stage.stl" to "Base, Cover.stl" using three "Bolt.stl".
• Attached the momentary push button switch to the cover.
• Soldered a yellow wire to the LED anode lead then insulated it with heat shrink tubing.
• Soldered a blue wire to the LED cathode lead.
• Pressed the salvaged flame into "Adapter, Candle.stl".
• Pressed the wired LED assembly into the flame.
• Routed the wires through the top of "Candle, Tower.stl", then pressed the LED assembly into the top of the tower.
• Repeated this process with the remaining LED, adapter and candle tower.
• Inserted the wires through the small holes in the top cover assembly, then attached both LED assemblies to the top cover assembly using small dots of cyanoacrylate glue.

Step 4: Mirror and Mirror Frame Assembly.

For mirror and mirror fame assembly, I:

• Positioned "Mirror.stl" over a sheet of mirrored acrylic.
• Marked the outside edges and center hole on the mirror using an indelible ink pen.
• Cut the outline of the mirror using sharp shears.
• Drilled the center hole using a 7.4mm drill bit (or hobby knife, use a backing if drilling).
• Removed the protective cover on the face side of the mirror.
• Placed the mirror in "Frame, Front.stl".
• Placed "Frame, Rear.stl" over the front frame assembly.
• Secured the frame assembly to the base assembly using two "Bolt, Frame.stl".

Step 5: Wiring.

For wiring, I:

• Slid the top cover assembly over the base assembly and secured it in place using four "Bolt.stl".
• Soldered two blue wires, one on each terminal, to the pushbutton switch.
• Soldered the battery case black wire, one of the pushbutton blue wires and one of the green reed switch wires together then insulated with heat shrink tubing.
• Soldered the battery red wire and the candle yellow wires to the motor red wire.
• Soldered the remaining reed switch green wire, the candle blue wires, the remaining push button blue wire and the motor black wire together then insulated with head shrink tubing.
• Secured the wiring in place using small dots of cyanoacrylate glue, making sure the wires remain clear of moving parts.

Step 6: Body Assembly.

For body assembly, I:

• Positioned "Cam, Axle, Arms.stl" into "Body, Shoulder.stl", slid "Axle, Arms.stl" into position making sure the cam was centered on and perpendicular to the axle, then secured the cam to the axle with small dots of cyanoacrylate glue.
• Attached "Arm, Left.stl" and "Arm, Right.stl" to the axle using cyanoacrylate glue, making sure the arms rotationally aligned with each other on the axle, and that the arms easily rotated.
• Glued the shoulder assembly to "Body.stl" using small dots of cyanoacrylate glue.
• With the arms in the full down position (on the body knees), glued a 6" piece of black polyester thread to the top of the cam such that the thread followed the cam towards the rear of the body assembly.
• Threaded the free end of the polyester thread out the rear hole in the body assembly, then pulled the thread to make sure the arms raised and lowered freely.
• Attached "Head.3mf" to the body using small dots of cyanoacrylate glue.
• Attached the two "Hand.stl" to each arm using a small dot of cyanoacrylate glue such that the palms were up and the thumbs were out.

Step 7: Final Assembly.

For final assembly, I:

• Threaded "Mount, Body.stl" through the mirror and into "Yoke.stl".
• With the batteries installed and the power switch on, operated the push button to make sure the mechanism cycled then stopped, making slight adjustments to the reed switch position as needed for correct operation.
• Manually rotated the gear motor gear until the mirror was at its top most position.
• Threaded the polyester thread from the body assembly through the body mount.
• Pressed the body assembly on the body mount then secured in place with a small dot of cyanoacrylate glue, making sure the thread was free to move the arms up and down and the body base would not catch on the frame when lowering.
• With the mirror at its top most position, used a small clamp to hold and adjust the thread such that the arms were up but not over center.
• Glued the thread onto the frame rear with cyanoacrylate glue.
• Using double sided tape, secured one of "Panel, Short.stl" to each end of the assembly.
• Using double sided tape, secured one of "Panel, Long.stl" to the front and rear of the assembly.
• Applied a generous supply of light machine oil to the polyester thread via the body mount.

And that is how I 3D printed and assembled "Levitation, A 3D Printed Automaton Illusion".

I hope you enjoyed it!