3D Printing

3D Parts

STL files for 3D printing are oriented to print "as-is" on FDM style machines. Original design source may be downloaded using the links below.

Slicing Parts

We 3D Printed the head with dual-extrusion so the eyes and mouth are dark when the lights are on. The model has a thin shell and it can be printed without any support material.

  • PLA filament 220c extruder
  • 0.2 layer height
  • 10% gyroid infill
  • 60mm/s print speed
  • 60c heated bed

Snap Fit Mount

The Circuit Playground Express PCB snap fits into the case. Insert the PCB at an angle to fit under the snap. Line up the stand offs with the mounting holes and press down to snap fit.

Threaded Parts

The top and bottom parts are designed to screw into the LEGO head.  The threads are mostly angled surfaces that 3D print without support material.

Design Source Files

The project assembly was designed in Fusion 360. This can be downloaded in different formats like STEP, SAT and more. Electronic components like Adafruit's board, displays, connectors and more can be downloaded from our Adafruit CAD parts GitHub Repo.

CAD Assembly

The components were modeled in the cad assembly. This animation shows where the electronics are mounted and how the top and bottom screw into the base.

Speaker Holder

The speaker holder will need to be super glued to the top stud. The speaker holder should be centered with the speaker grill on the top stud. 

Press Fit Speaker

The speaker is press fitted into the holder and has a snug fit. The sticky adhesive is not necessary so you can leave the protective backing on.

Installed Speaker Holder

A small notch in the speaker holders lip accommodates for clearances for the pico connector and wiring.

Speaker Placement

The placement of the speaker sounds best when it's facing up, pressed up against the speaker grill. When the top is installed the LEGO head sound is amplified and much louder.

Install CPX to Mount

Orient the USB port with the opening and line up the mounting holes. Insert the PCB at an angle to get underneath the snaps. Firmly press down to snap fit the PCB into place. 

Connect the Alligator Clips to CPX

Grab the JST cable and connect the alligator clips to pads. Red to 3.3V pad, white to A0 pad and black to GND pad. Be sure the alligator clips have a sturdy grip on the Circuit Playground Express.

Install Case to Head

Insert the JST cable into the bottom of the LEGO head and screw in the case. 

Connect STEMMA Speaker

Grab the JST cable from top of LEGO head and plug it into the JST port on the STEMMA Speaker.

Install Top to Head

Twist the top stud onto the LEGO head to install it.

USB Power

Use a microUSB cable with a data line. You can leave it plugged into a 5V USB wall adapter or computer's USB hub.

This guide was first published on Sep 25, 2019. It was last updated on Sep 25, 2019. This page (3D Printing) was last updated on Oct 14, 2019.