WEEK 5
Head Assembly (19 Servos)
Complete head with all 19 servos, working eyes with iris, cameras + mic installed.
Est. Hours
35h
Est. Spend
$0 (parts arrived Week 1)
Tools Required
soldering ironRaptorX scannerCA glue + acceleratorepoxysandpaper (400-800 grit)Arduino MegaPCA9685
CAD FILES
head_shell_assembly.sldasmeye_gimbal.sldasm
PRINT FILES
iris_mechanism.stleye_gimbal_frame.stlcamera_bracket_cf.stl
Goal
Complete head with all 19 servos, working eyes with iris, cameras + mic installed.
The head is the most detail-intensive part of J5. It comes in Month 2 because: (1) you’ve practiced print post-processing on track covers, (2) you’ve done basic servo wiring on the RC system, (3) you’ve learned scan-verify on the torso. Now apply all those skills at higher precision.
Day-by-Day Tasks
| Day | Task | Method | Notes |
|---|---|---|---|
| 1-2 | Finish head shell post-processing | Sand 400→800, final primer coat | Should be smooth to the touch. No visible layer lines. |
| 2 | Assemble head shell sections | CA glue + accelerator, then epoxy structural seams | Multi-part prints bond together. Use CA for tack, epoxy for strength. Clamp and let cure 24hr. |
| 2-3 | Build eye assemblies | 3D-printed iris mechanism (Hytech76 STLs), SG90 servo, LED ring | Print iris parts in multi-color (black interior + metallic ring). Servo-driven diaphragm. Test open/close. |
| 3 | Install 89mm aluminum eye tubes | Epoxy into head shell | Alignment CRITICAL. Use RaptorX to verify tube parallelism before epoxy cures. |
| 3-4 | Build eye gimbal | 2 servos per eye (HS-645MG), 3D-printed gimbal frame | L/R + U/D per eye = 4 servos total for eye movement. Test range of motion before installing in head. |
| 4-5 | Install remaining head servos | HS-645MG x4 (flaps, pop), HS-485HB x5 (nose, basket, vents), SG90 x6 (antenna, radar, mic arm) | 15 more servos. Wire to PCA9685 board. Label every servo wire. |
| 5-6 | Wire all head servos to PCA9685 board(s) via I2C | Soldering, JST connectors | First serious soldering work. Practice on spare wire first. Clean joints, heat shrink every connection. |
| 6 | Install Pi Camera between eyes | Mounting bracket (CF print) | Camera looks through the space between the eye tubes. |
| 6-7 | Install ReSpeaker 4-mic array | Mount in “ear” position | Wire to Pi 5 via USB. |
| 7 | RaptorX: Full scan of completed head | RaptorX | Verify eye alignment, servo clearances. This scan is your head reference for any future repairs. |
| 7 | Test all 19 head servos | Arduino + PCA9685, sweep test script | Every servo moves to min/center/max. Fix any binding, clearance issues, loose linkages NOW. |
Skills Practiced
Precision 3D print assembly, soldering (20+ joints), servo gimbal alignment, scan-verify at tight tolerances.
Print Queue
Arm covers → fingers → RaptorX dovetail mount → misc adapters