Engi and V reviewed the USB test PCB.

Mavleague presented new chassis concept renders

Design issues:

• need to space out privacy switches
• cnc chassis needs to be separated into multiple parts to be able to fit the PCB into the chassis for assembly
• TPU gaskets can be used for easy improvement of IP rating
• battery connector needs to be a standard small JST
• flash LED needs to be moved
• 90 degree LED flash diffusor idea
• data lines switch for USB idea

OliveOil wrote down a chassis development summary doc:

Date: 23/07/2026 Presented by: OliveOil & MavLeague
Status: Exploratory / Non-Final

This document outlines the first-stage design direction for the SPIRIT Phone chassis. The current vision prioritises a rugged, user-repairable, and modular aesthetic that empowers individual makers. The design is fluid; these renders and concepts are intended to spark feedback and guide prototyping, not to lock in final specifications. Close collaboration between the Chassis and PCB teams is essential moving forward.

• User Repairability: The device is designed to be easily disassembled by anyone with standard tools. Visible screws are a deliberate choice to signal this capability.
• Modularity: The chassis consists of three main parts: a central body (frame), a front panel, and a back panel.
• Visual Cohesion: A consistent language of shapes (circles, squares, and pill shapes) unifies the design.
• Rugged Durability: The form factor embraces a thickness of ~20–22mm to ensure durability and accommodate internal components, utilizing chamfers and fillets to improve ergonomics.

• Structure: Three-part assembly (Front Panel, Middle Frame, Back Panel) fastened with standard Torx screws (likely M2 or M3).
• Manufacturing Strategy (Recommended Hybrid Approach):
  • Main Frame: CNC machined aluminum for structural integrity and heat management.
  • Front/Back Panels: 3D printed using SLS in PA11 (Nylon derived from castor bean oil) for sustainability, complex geometry, and cost-effectiveness for individual makers.
• Fasteners: Visible countersunk screws. While shown as chrome silver, they can be anodized to match custom color schemes. Rear screws can be used to also attach accessories (e.g., lanyards), inspired by the Nothing CMF Phone.

• Form Factor: Intentionally rugged with chamfered edges on all panels and screen bezels to create a visual illusion of thinness.
• Colorway: Current concept features a Black and Yellow accent scheme to emphasize durability and a DIY ethos, though CMF (Color, Material, Finish) is open to change.
• Shape Language: Pill-shaped cutouts are used for speaker grilles (front) and the flash diffuser (back) to create visual hierarchy and consistency.

• Heatsink: A separate, machined piece for the Raspberry Pi Compute Module 5. It slots into the case to maintain fidelity and allow heat radiation. Note: Current heat sink cutouts size is likely too large and requires tuning.
• Display: Mounted to the back of the front panel using foil tape. This eliminates the need for complex extra retaining components for the thin/flimsy screen.
• Camera & Flash:
  • Dedicated cutout for the camera module.
  • Flash diffuser made from translucent plastic (Perspex, Polycarbonate, or 3D printed clear PETG) with an opaque filter to diffuse light evenly.
• Buttons: Power, Volume, and privacy-focused buttons feature accent colors (currently yellow) for distinction.

To improve usability and reduce thickness, the following changes to the PCB design are requested:

1. Battery Connector: Replace the current screw terminal with a push-fit connector. This reduces thickness and simplifies battery removal without tools.
2. SD Card Slot (actually SIM card slot): Relocate to the edge of the PCB to allow for an easy-access slot for on-the-go storage swapping.
3. Storage Architecture: Clarification needed on OS storage. Will the OS reside on the removable SD card, or is there onboard storage? If onboard, can users expand storage via a second removable module?

The following areas require further research, testing, or team alignment:

• Heatsink Integration: Should it remain a separate visible unit or be integrated further?
• Flash Diffuser Material: Final selection between Perspex, Polycarbonate, or PETG.
• Panel Manufacturing: Final decision on whether front/back panels should be strictly 3D printed or machined.
• CMF Definition: Finalizing color, material, and finish options beyond the current black/yellow concept.
• PCB Constraints: Specific dimensions and component placements needed from the PCB team to lock the chassis design.

• Prototyping: Create 3D printed mock-ups of the current design to test ergonomics and "hand-feel."
• Cross-Team Sync: Initiate close coordination between Chassis and PCB teams. No design should be locked without mutual agreement, as changes in one directly impact the other.
• Connector Redesign: Update PCB design to accommodate the push-fit battery connector.

• Design Office Hours: Establish a bi-weekly 1–2 hour sync for design reviews, issue resolution, and task delegation.
• Iterative Testing: Use physical prototypes to refine dimensions (especially the heatsink and overall thickness) before finalizing any manufacturing files.

---

Note: This document represents a "Work in Progress." All elements are subject to change based on prototype testing and team feedback.

(voicechats between 2026-04 and 2026-07 where not summarized)

• Analyzed Librem 5 USB C 3.x implementation
• Found MUX and choke + ESD protector
• Found USB 2 MUX with built in ESD TS3USB221AQRSERQ1
• USE the PG_STAT register of the BQ25792 to drive the USB MUX

• Moved fast signal to outer layer for easier calculation of Z diff
• Stitching vias
• Talked about Engi's camsat

• Discussed EG25 in context of power saving features and usage.
• 16:30 GMT0
• Switch PCM signals between EG25/codec, OR better: use EG25 over USB.
• Found problems in the pwr layout

TODO for V

• Add 4.7k pullups in 0805
• Research via diameter impact on pricing with pcbway
• Ask pcbway about cost drivers file
• Inductor lines should be thicker
• Calculate usb diff pair for 72ohm

• Merged PCB layout change from Engineer
• Merged audio schematic by Engineer
• Fingerprint scanner driver issue
• Discussed weird pinephone schematics
• Got EG25 hardware design doc
• Created SPIRIT-org github organization

V todo list:

• Swap 3.3V to 1.8V in mic privacy switch
• Route pwr
• Review/find reviewer for audio
• Fix USB C footprint, move board cutout from footprint to main PCB
• Automate populating value and tolerance fields of components with python

• Driver team progress
• Power section schematics need double check, seems complete
• LCSC BOM reading problem probably caused by "$\mu$" solution: just use MPNs, and if some fail or are unavailable just do it by hand. Engineer tested this and it's fine. (This should be fixed in the symbols itself in the future)
• Engineer did phd level screen research
• Updated PCB layers descriptions

V's TODO:

• Research and decide on physical stackup
• Recalculate trace thickness for main power rails in Octave in /math
• Start routing the power PCB
• CM5 connectors should not be DNP, include them in power PCB

• USB C connector broken in 3D model
• Need to decide which I2C lane for TPS65023B
• Potentially swap battery connector for a smaller one
• Top left hole on PCB is misalligned with CM5, offset: X:-0.5 Y: 0.3 (image in audio chat)
• Flash LED is too low, use a THT LED with longer legs
• Rectangular LED around camera idea. Could be done as an LED array with difuser. Rejected as too complicated.
• Rails solution for addon mounting is mid.
• Simple hex screws for mounting addons, use the step at the bottom of the phone for alligment

Driver info:

• Using I2C0 for PMIC
• Using MIPI1 for Screen

• Merged Engineer PR
• Decided to disconnect RESPWRON
• SPIRIT mentioned on adafruit !!!
• meta Spirit Wanderer PR reviewed

• This note is intended for American team to read later
• New PMIC PR by Engineer merged
• Better flowchart by w-w using mermaid, draw.io or something else. Come back to the subject next week.

NOTES FOR AMERICAN TEAM 💙

Dear americans:

• GDabomination please export the 3,5mm jack 3D model you made last time as .step and make a PR adding it to the SPIRIT/EDA-kicad/component-libs/SPIRIT-3D-models directory. Please replace the old one and make sure the filenames are 100% identical. Please tell Mavleauge from chassis team when it is ready so he can fix the onshape project error. Thank you!

• We are looking for contributors for the Audio and GPSGSM schematics. (One person per schematic). Both of these schematics are high priority and they should be present in prototype 1 of SPIRIT. If there are any volunteers please ping V on discord. All major components are already chosen. audio issue GPSGSM issue

• Additionally a smart standard for external addons needs to be brainstormed and invented. I opened an issue with a brief description. In the past magnetic pogo pins have been proposed.

TODO list for V

• Continue reviewing the power schematic
• Delete old spirit symbols in favor of components
• Delete library merger
• Delete/fix in EDA-kicad/design-block-lib-table (lib (name "SPIRIT-symbol-libs")(type "KiCad")(uri "${KIPRJMOD}/component-libs/SPIRIT-symbol-libs")(options "")(descr ""))
• VRTC capacitor change to 4.7 uF
• Fuse between Battery and BQ, consider resetable fuse
• In contrib guide mention "good first issues"
• Start routing power section PCB
• If no one wants to volunteer for GPS GSM or audio make an announcement on Discord/YT

• Congratulations!!! We have been mentioned in 2 articles this month!!! Jeff Geerling commented on the article on hackaday.
• USB C footrprint bugged, no big deal, easy to fix
• 35mm jack 3D model problem
• 2 meetings per week idea
• TODO vote for a time and set new weekly meeting for american contributors
• TODO update wiki
• TODO similar projects wiki by tymk
• pibrick can be used for inspiration https://amarullz.com/2025/07/16/pibrick-a-building-block-for-handheld-computing/
• Engineer finished power, will be reviewed and merged next week (!!!).
• TODO fix spirit symbols lib throwing erros, probably just delete it. SPIRIT-symbols is the new library
• TODO check if there's 2 symbols for MP3429 and fix. Check if deleting standalone symbol doesn't break anything.

Nema PR 86

link

TODO Simulate buttons encoding system with low quality resistors and check if all combinations are readable by the GPIO. Falstad can be used.

TODO add symbols, footprints, models as per contrib guide

new LED driver suggestion

LED driver files

New much more powerful LED has been suggested, no link provided yet

V: my take on this: I think it makes more sense to leave the LED situation as is i.e. use the smaller LED and use the current MOSFET driver along with optional PWM to change the brightness. PWN can also solve the potential heat issue in my opinion. Old LED heat dissipation assuming 40% efficiency $\large \displaystyle P=0.6 \cdot 3.3V \cdot 0.350A = 0.63$ W $\large \displaystyle \implies$ probably no heat issue

Electronics

Found eda files for new power driver, pasted .zip in chat

Instead of shutting down the camera consider disabling it pulling pin 11 on the connector down with a switch. This is cheaper and solves the camera rediscovery issue, caused by full camera reboot

PMIC EN pin and others in that corner of the cm5 connector are potentially very useful, research should be done.

pr 84 will probably be rejected however it points out some potential problems. We didin't analyze it fully

Other

Cool cnc mill (:::

Ignore hinge mechanism for now as it is low priority

Would be nice to form independent teams

Perhaps we could have voicechat at different times so people from other time zones/lifestyles can join

• New popup camera concept presented
• Is screen standardized? Not a problem because the models are parametric
• Disconnectable wireless camera concept??? Perhaps make it as an addon.
• Addon pogo pins need to be on the side probably
• Mount addons into rails with latches? Screws?
• Multiple versions released e.g. no addon connector version, rail version, magnetic addons version etc.
• Brass, bronze or other cool metal buttons can be made for fun
• Threaded inserts or custom Mavleague screw
• Open source laptop / tablet https://source.mnt.re/explore/projects/starred
• Adapt to MNT ecosystem
• Use one gpio for all buttons, resistor encoding / I2C
• Potential problem: submodules need to react gracefully to power disconnect. Needs to be tested. Can be fixed with a coprocessor.
• Coprocessor can provide deep sleep/hibernation functionality. "Fake off" function.
• TODO test if camera can be powercycled without rebooting OS

• Olive is an industrial/technical designer (based)

• Sourcing protective glass is a problem. Found gorilla glass stock ~300x300mm ($100) https://www.mcmaster.com/4205N18/

• Gorilla glass standardized? (no) Find alternatives

• 3d print jig for gorilla glass grinding

• Use existing glass protectors with adhesives.

• "Parts passports", provide document for users stating source and info about all components

• Rethink some chassis stuff, 3d renders (mav & oil)

• Save chassis versions as it progresses

• Processor bump chamfer now fits your finger comfortaly!!!

• Effect lenses, e.g. fish-eye

• TODO: make design brief for chassis (and also potentially motherboard other subsystems)

• Post it on the wiki

• Connecting the screen (TOP055FHDTOOCTP01) to the frame is a lil' problem. Olive found a solution

• Olive made a design inspiration Pinterest board https://pin.it/1S6aAGIii

• PHA bioplastic, hydrophobic, foodsafe, biodegradable filament (literal bacteria lol) can be used for the chassis

• Weekly voicechat meatings (extremely good idea) thursday 19:30 GMT+1