Parts.

I acquired the following parts:

• One 3.7vdc 100ma Lithium Battery (https://www.adafruit.com/product/1570).
• One JST PH 2-Pin Cable (https://www.adafruit.com/product/3814).
• One N20 6VDC 100RPM gear motor.
• One micro switch (Uxcell a12013100ux0116 High Knob 3P 2 Position 1P2T SPDT Vertical Slide Switch, 0.5 Amp, 50V DC, 50 Piece, 3 mm).

I 3D printed the following parts at .15mm layer height, 20% infill, and no supports:

• One "Axle, Eyes.stl".
• Two "Axle, Leg.stl".
• One "Base.stl".
• One "Cam And Axle.stl".
• One "Cam.stl".
• One "Chassis.stl".

Either:

• One "Eyes, Black.stl".
• One "Eyes, White.stl.

Or:

• One "Eyes.3mf".

Then:

• One "Gear, Crown, Axle.stl".
• One "Gear, Crown, Motor.stl".
• One "Heart.stl".
• Two "Leg.stl".
• One "Tie.stl".

This is a precision print and assembly model using at times very small parts and in very tight spaces. Prior to assembly, test fit and trim, file, sand, etc. all parts as necessary for smooth movement of moving surfaces, and tight fit for non moving surfaces. Depending on you printer, your printer settings and the colors you chose, more or less trimming, filing and/or sanding may be required. Carefully file all edges that contacted the build plate to make absolutely certain that all build plate "ooze" is removed and that all edges are smooth. I used small jewelers files and plenty of patience to perform this step.

The model also uses threaded assembly, so I used a tap and die set (6mm by 1) for thread cleaning.

Chassis Assembly.

To assemble the Chassis, I performed the following steps:

• Soldered the switch and JST connector the the motor so that the motor, when viewed from the axle end, rotated clockwise.
• Pressed the motor assembly into "Chassis.stl".
• Pressed "Gear, Crown, Motor.stl" onto the motor shaft.
• Positioned "Gear, Crown, Axle.stl" into the chassis assembly, over the small chassis side hole.
• Slid "Cam And Axle.stl" into the large chassis side hole, through the axle crown gear, and out the small chassis side hole.
• Pressed "Cam.stl" onto the cam and axle such that it was 180 degrees out of phase with the cam on the cam and axle.
• Secured one "Leg.stl" to the chassis assembly using one "Axle, Leg.stl".
• Repeated the previous step for the remaining leg and leg axle.

Final Assembly.

For final assembly, I performed the following steps:

• If you printed the eye black and white components separately, press the two "Eyes, Black.stl" into "Eyes, White.stl".
• Positioned the eye assembly into "Heart.stl".
• Secured the eyes to the chassis assembly using "Axle, Eyes.st" such that the pivot arms of the eye assembly rested on the pins on the legs.
• Pressed "Base.stl" onto the chassis assembly and secured in place using two small dots of glue (use small dots such that if disassembly is required, the dots can be cut away).
• Slid the base assembly into the heart assembly and secured in place with two small dots of glue between the upper edge of the base assembly and the hear (again the small dots are cut away if disassembly is required).
• Plugged the battery into the JST connector and slid the battery into the heart.
• Glued "Tie.stl" to the base assembly.

I applied power to the model, and off it walked looking for a Valentine!

And that is how I 3D printed my "Valentine Heart Pinwalker."

I hope you enjoyed it!