# Walkie One 28.1 / R3.4 - start here

Website version **28.1** = engineering **R3.4 Print Prototype**, prepared 14 September 2026. R3.4 filenames are intentional. This is the R3.3-derived branch; keep it separate from 28.2 and earlier R3.2 A files.

Current page: https://walkieone.com/cad-handoff/concept-28-1

1. Read `Walkie_One_28_1_R3_4_Engineering_Handoff.pdf` for the current scope, parts, materials and open checks.
2. For P1S / 0.4 mm / PLA printing, use `Walkie_One_28_R3_4_PRINT_THIS.zip`. Open its four main 3MF projects individually in Bambu Studio. Print each once at 100% scale. The 21 STL files are alternatives, not an additional set.
3. Optional plate 05 contains two optical fit proxies. F01 rim and F02 talk grip have separate flexible-material STLs; the rigid PLA profile does not reproduce their function.
4. For CAD review, use `Walkie_One_28_R3_4_REFERENCE_ASSEMBLY_NOT_FOR_SLICER.step` or the full-reference F3D. STEP and STP are the same interchange format. This full assembly contains purchased/reference geometry and gauges; do not fabricate every body.
5. Use the 25 individual current STEP/STL IDs in `Part_Schedule.md` for the print-design parts; `Walkie_One_28_R3_4_PRINT_PARTS_ONLY.f3d` isolates those parts for Fusion.
6. Record physical results in `First_Article_Checklist.md` before approving an assembled build or supplier process. Use `Release_and_Verification.md` to identify exact CAD files.

## Current scope

Rigid case: 78 x 150 x 24 mm. Electronics and controls retain the R3.3 layout. The rim/buttons project beyond that envelope; the printed grille bezel projects 1 mm farther forward than R3.3.

No extra 0.40 mm switch-seat shims or paired 0.10 mm stop shims: they are integrated. P03/P06/P07 integrate their cosmetic caps. Mesh, screws, electronics, pads and films are purchased/nonprinted components.

This is a frozen geometry checkpoint for prototype printing and engineering review. The 1 mm structural wall screen and slicer checks passed; this does not establish installed switch, complete harness, optical, RF, thermal or production-process qualification. Future edits must receive a new revision and new files.

## Open the files in this ZIP

- [Engineering handoff PDF](Documents/Walkie_One_28_1_R3_4_Engineering_Handoff.pdf)
- [Printability explainer PDF](Documents/Walkie_One_28_R3_4_Printability_Explained.pdf)
- [Exact printer ZIP](Printing/Walkie_One_28_R3_4_PRINT_THIS.zip)
- [Printer setup instructions](Printing/START_HERE.txt)
- [Full reference STEP for CAD review](CAD/Walkie_One_28_R3_4_REFERENCE_ASSEMBLY_NOT_FOR_SLICER.step)
- [Part schedule](Documents/Part_Schedule.md)
- [Assembly and purchased parts](Documents/Assembly_and_Nonprinted_Parts.md)
- [Materials and colour targets](Documents/Materials_and_Colour_Targets.md)
- [Changes video](Video/Walkie_One_28_R3_4_Changes_Explained.mp4)

`CAD/Individual_STEP` contains the 25 print-design STEP parts. `Printing` contains the five projects and role-separated STL files. `Verification` holds digital checks; use the dated handoff to interpret inherited reference evidence. `3D_Preview` and `Images` are display assets, not fabrication files.