Introduction: Mycroft Mark II 3D Printed Developer Kit Assembly

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To build a Mark II 3D printed Dev Kit you will need to first print the following parts on a FFF printer. In this build all parts are printed in white with the exception of the MKII Display Bezel, which is printed in Black. All of the STLs are oriented correctly for printing, but I suggest you combine and nest as many parts as possible in your chosen slicer to reduce print time. Only two parts need support, 7. Mark II Center Button and 11. Mark II Top, all of the rest can print without any supports.

  1. MKII Audio Chamber
  2. MKII Back
  3. MKII Body
  4. MKII Camera Shutter 1
  5. MKII Camera Shutter 2
  6. MKII Camera Shutter 3
  7. MKII Center Button (support needed)
  8. MKII Display Bezel
  9. MKII Display Housing
  10. MKII Grill
  11. MKII Top (support needed)
  12. MKII button (x2)
  13. MKII switch
  14. MKII wire holder
  15. MKII Door

The STL files can be downloaded here:

https://github.com/MycroftAI/hardware-mycroft-mark...

Step 1: Unpack Your Kit

Included in the Kit are the following items:

  • SJ201 Mycroft Audio Pi Hat
  • 1.5" Speaker Drivers
  • Power supply (12v 3A)
  • 10x M2.5 x 12 mm screws
  • 35x M2.5 Threaded inserts
  • 12x M2.5 x 10mm screws
  • 9x M2.5 x 6mm screws
  • 4x M2 Threaded inserts
  • 4x M2 x 8mm screws
  • 4 Blue Speaker Grommets
  • Raspberry Pi 4b 2GB
  • Raspberry Pi Heatsinks
  • Fan
  • USB Drive 16gb
  • 4.3" LCD touch Display
  • Display Cable (DSI)
  • Wire holder
  • 4x Grommet insert spacer
  • 4x Foam Microphone Gasket
  • Tweezers
  • Alcohol Wipe
  • Instruction Card

Step 2: Clean Up 3D Printed Parts

Remove any brim, raft or scaffolding from the parts. Make sure the mating surfaces are free of stringing or other print defects.

Step 3: Audio Chamber: Add Threaded Inserts

The Audio Chamber uses 10 m2.5 (3mm diameter x 4mm length) heatset threaded inserts. Using a soldering iron place the threaded inserts into the 8 mounting holes for the speaker drivers as well as the 2 holes for securing the wires. Once the threaded insert is heated it easy to push into the hole, be careful removing the soldering iron occasionally the threaded insert can stick to the tip of the iron.

Step 4: Display Housing: Add Threaded Inserts

Add 6 m2.5 threaded inserts to the Display Housing.

Step 5: Body: Remove the Scaffolding

The Mark II Body has a built in scaffolding (no extra support is needed during printing). The scaffolding needs to be removed. There is a support for the center of the arched door opening, and 4 supports for the Grill mounting bosses that are setback from the print surface.

Step 6: Body: Add Threaded Inserts

Add 11 m2.5 threaded inserts to the Body:

  • 4 for mounting the fan on the side
  • 1 for securing the door
  • 2 for moutning the top
  • 4 for mounting the audio chamber

Step 7: Grill: Add Threaded Inserts

Add 4 m2.5 threaded inserts to the grill.

Step 8: Top: Add Threaded Inserts

Add 4 m2 threaded inserts to the top. This is the only part that uses the smaller m2 screws and threaded inserts.

Step 9: Display Housing Assembly

To assemble the display housing you will need the following parts:

  • Display Housing
  • Display Bezel
  • LCD DSI 4.3" Display
  • Camera Shutter 1 (optional)
  • Camera Shutter 2 (optional)
  • Camera Shutter 3 (optional)
  • Camera (optional)
  • 8 m2.5 x 6mm screws
  • 2 m2.5 x 10mm screws
  • Alcohol wipe

On the Display Housing clean the square camera mount with the Alcohol Wipe to promote good adhesion. Next remove the paper covering the adhesive on the camera and place it in the square camera mount on the Display Housing. Next place the Camera Shutter 1 over the camera. Then stack Camera Shutter 2 on top of Camera Shutter 1 (Camera Shutter 2 is the sliding mechanism) Finally, place Camera Shutter 3 on top of Camera Shutter 2 and secure with 2 m2.5 x 10mm screws.

Next, remove the outer film from the screw mounts on the LCD display. These mounts are how the LCD display attaches to the Display Housing. Place the Display in the Display Housing with the thinner bezel facing up toward the camera. Then Fish the camera cable around the back of the display and out the back of the Display Housing. Use 4 m2.5 x 6mm screws to attach the LCD display to the Display Housing.

Last step, place the Bezel into the housing and align the hole with the camera. Secure from the back with 4 m2.5 x 6mm screws.

Step 10: Combine Display Assembly and Grill

You will need the display assembly, the grill, and 4 m2.5 x 12mm screws. To attach the display to the grill align the Camera ribbon cable (CSI) and Display ribbon cable (DSI)with the slot in the grill. Feed the ribbon cables through the slot. Align the grill with the 4 mounting holes on the Display Assembly. Attach the Grill to the Display Assembly with 4 m2.5 x 12mm screws.

Step 11: Attach the Display Assembly + Grill to the Body

Using 4 m2.5 x 8mm screws attach the Display Assembly + Grill to the Body.

Step 12: Top Assembly

To assemble the Top Assembly you will need:

  • Mark II Top
  • SJ201
  • Mark II Center button
  • Mark II Button (x2)
  • Mark II Switch
  • 2 foam microphone gaskets
  • 4 m2 rubber dampening mounts
  • 4 m2 x 8mm screws

Remove the SJ201 from the static bag and add the 4 m2 rubber dampening mounts to the 4 holes in the SJ201. Next use 2 of the foam microphone gaskets and apply them to the underside of the Top piece aligned with the microphone holes.

Next set the top face down and place the center button, two buttons, and switch into their respective openings. With the Top placed face down and the switch/button opening facing away from you the switch is on the left. Carefully place the SJ201 onto the Top and make sure the switch is aligned. Secure the SJ201 in place with 4 m2 x 8mm screws.

Step 13: Assemble the Audio Chamber

To assemble the audio chamber you will need:

  • The audio chamber
  • 2 1.5" speaker Drivers
  • 10 m2.5 x 10mm screws
  • 1 wire holder
  • Hot glue gun and hot glue

Place the left Speaker Driver cable through the left opening and thread the speaker wire connector through the opening in the back of the Audio Chamber. Secure the Left Speaker Driver with 4 m2.5 x 10mm screws. Repeat the process for the right speaker driver securing it with 4 m2.5 x 10mm screws. Make sure the wire are on the correct side (the Left wire will be slightly longer) and glue the wire holder in place with hot glue sealing the wires to create an air tight seal. Secure with 2 m2.5 x 10mm screws.

Step 14: Add Heatsinks to the Raspberry Pi

Add heatsinks to the Raspberry Pi 4 as shown

Step 15: Flash Mycroft Software Onto the USB Drive

Download the image here

Windows/MacOS/Ubuntu If you are using Windows, MacOS or Ubuntu use the Raspberry Pi Imager to flash the custom image you downloaded onto the provided USB drive.

NOTE: You must choose the "Use Custom" option and select the image you downloaded.

Once complete put the USB drive into the Raspberry Pi USB 3.0 port as shown.

Step 16: Combine the Top Assembly and Raspberry Pi 4

Combine the Top Assembly and Raspberry Pi 4 with the 40 pin connector.

Step 17: Attach the Fan to the Body

With the Wires facing the top and the label facing out attach the fan to the Mark II Body with 4 m2.5 x 12mm screws.

Step 18: Attach the Top Assembly to the Body

Connect the Display Ribbon Cable (DSI) to the Display Connector (DSI) on the Raspberry Pi 4 on the edge of the board near the SD Card slot. Make sure the connectors are facing toward the center of the Rapsberry Pi board and not toward the edge. The cable needs to twist 180 degrees for proper alignment. Attach the optional Camera cable (CSI) to the Camera connector (CSI) on the Raspberry Pi 4. Again, make sure the connectors are oriented correctly. See the photo for proper orientation. Connect the 4 pin Fan cable to the SJ201, it's a directional connector with a key, it can only be assembled one way.

Carefully place the ribbon cables between the Raspberry Pi and the Grill. Slide the Top Assembly into place, it will friction fit into two slots on the body. It will be later secured in the back with two screws.

Step 19: Place the Audio Chamber Into the Body

Add the 4 Blue Grommets (for anti-vibration) to the hooks in the Audio Chamber. Place the two Grommet Insert Spacers in the upper two grommets. Carefully slide the Audio Chamber into place, the Grommets should meet up with the 4 Audio Chamber mounting bosses on the Body. Secure the top two mounts with 2 m2.5 x 12mm screws. The bottom will be secured through the Back piece.

Step 20: Attach the Back to the Body

Using 4 m2.5 x 12mm screws attach the Back to the Body. The top two holes will sandwich the Back, Top, and Body securely together. The bottom two holes will sandwich the Back, Audio Chamber, and Body securely together.

Step 21: Add the Door

Using one m2.5 x 6mm screw attach the door to the side of the body.

Step 22: Add Feet

Add feet to the bottom of the Body. The feet we are using now are replacement laptop feet with a diameter of .7"

Replacement Laptop feet

Step 23: Assembly Complete!

You're all done, now it's time to enjoy your Mark II 3D printed Dev Kit. Before you get started visit account.mycroft.ai to create an account. You will need an account to pair your device. Next, plug in the power supply and follow the prompts to set up wifi and pair your device. Happy hacking!