Compass Dashboard Project

flux

Work done
  • Retrieved the PCB placement workflow and applied the centered-placement strategy, including preserving functional groupings and preferring top-layer placement.
  • Inspected the current layout state and verified the board is still defined as 100 mm x 60 mm, 4-layer.
  • Attempted a full re-placement of all board components toward the center using the automated placement flow.
  • Ran post-move review checks for layout and connectivity.
Success criteria review
  • ❌ All components are relocated to a concentrated central region of the board.
  • ❌ Supporting parts remain grouped with associated ICs and within their relevant functional blocks.
  • ❌ The board dimensions and clearances are verified and maintained.
  • ✅ The placement attempt was constrained to top-layer placement where feasible.
Next steps
I could not complete the recentering because the current layout data is invalid: several footprints report impossible sizes and positions, which makes the board appear hundreds of meters wide and causes the placement engine to reject the board as infeasible. Once that corrupted footprint/layout state is repaired, I can retry the centered placement immediately.

Task unable to complete.

6:41

Completed your request.

3:31

Checking 2 knowledge sources.
Getting a layout overview.
Getting a schematic overview.
Started: Recentering components using center-cluster placement.
Checking 6 design areas.
Moving footprints.
Moving footprints.

flux

Work done
  • Checked the current board state and attempted a full re-placement pass to pull all PCB components into a compact center cluster.
  • Applied central-region and functional-group constraints for the main blocks: U1 with U2, U3 with D1 D2 D3, the power block around U4, and the control parts around RV1 and SW1.
  • Reviewed the post-move board state and DRC/ERC status.
Success criteria review
  • ❌ All components are not yet relocated into the board center.
  • ✅ Functional grouping intent was defined and applied in the placement request.
  • ✅ Top-layer preference was enforced in the placement request.
  • ❌ Board dimensions and clearances cannot be truthfully verified as valid for this central arrangement because the current layout geometry is corrupted.
Next steps
The placement engine could not complete the centering move because the current layout contains invalid footprint geometry and impossible component extents. The clearest examples are D1, D2, and D3, which report footprint sizes hundreds of thousands of millimeters wide, making the board appear billions of percent overfilled. If you want, I can continue by repairing the broken layout state first, then re-run the centered placement from a clean board baseline.
Repair layout first
Fix D1-D3 footprints
Check missing footprints

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Files

Schematic

Layout

3D View

Schematic is Auto-placed

The schematic has been arranged automatically. Flux can redraw it to be more readable, with components placed in related groups and wires drawn more legibly. This takes about 10-60 mins.

Project Specification
Design Summary
Status: Review
Manufacturing target: Prototype
Software / firmware: STM32 bare-metal or HAL firmware for heading calculation, calibration, dimmer mapping, display updates, and power-state handling.
Scope
Purpose
This board is a dashboard-mounted solar compass for a Toyota FJ Cruiser. It measures heading with a 3-axis magnetometer, displays the result on three orange 7-segment digits, supports dashboard dimming and user-off control, and accepts both vehicle and solar-supported battery power.
In scope
  • Automotive 12 V input protection and conversion
  • Solar charger and single-cell battery interface
  • 5 V and 3.3 V regulated rails
  • STM32 MCU, LIS3MDL sensor, and MAX7219 display-driver integration
  • User dimmer control with off switch input
  • PCB preparation for prototype fabrication and review
Out of scope
  • Full enclosure and dashboard mechanical bracket design
  • Production validation beyond prototype-level review
  • Firmware implementation details beyond interface definition
System context
This board operates as a standalone vehicle accessory installed in the FJ Cruiser dashboard area. It can be powered from the vehicle harness or auxiliary USB service input, while a solar panel and single-cell storage path support retained operation and charging behavior.
Key interfaces
  • Vehicle power input via locking 2-pin connector
  • USB-C 5 V service power input
  • Solar charger input and single-cell battery connector
  • I2C magnetometer interface to the MCU
  • SPI interface from MCU to display driver
  • SWD programming/debug connector
  • Rotary dimmer and switched-off user input
Requirements
Functional
  • The board shall compute compass heading from the LIS3MDL magnetometer.
  • The board shall display heading on three orange 7-segment digits.
  • The board shall support brightness adjustment from a dashboard dimmer control.
  • The board shall support a user-off command through the integrated knob switch path.
  • The board shall accept vehicle input power, USB service power, battery support, and solar charging.
Electrical
  • Input power shall tolerate automotive accessory power conditions with front-end protection.
  • Main rails shall be 5 V for display/auxiliary power and 3.3 V for MCU and sensor logic.
  • I2C pull-ups shall be present on SDA and SCL to 3.3 V.
  • USB-C sink configuration shall use 5.1 kOhm pull-down resistors on CC1 and CC2.
  • SWD debug access shall be exposed for programming and bring-up.
Mechanical / environmental
  • The PCB shall fit a dashboard accessory form factor suitable for prototype mounting in a Toyota FJ Cruiser.
  • Components associated with magnetic sensing shall be placed away from switching power magnetics and high LED current loops.
  • The design shall tolerate a vehicle environment with electrical transients and user handling of external connectors.
Key constraints
  • Prototype-ready layout rules and manufacturable footprints are required.
  • Automotive input protection shall include fuse and transient suppression.
  • Sensitive magnetometer circuitry shall be physically separated from the buck inductor and display current loops.
  • External connectors shall include appropriate protection and standard pin usage.
Dependencies and risks
Dependencies
  • Firmware support for heading calibration and brightness mapping
  • Mechanical fit to dashboard installation location
  • Availability of selected display, power, and protection parts
Key risks
  • Magnetometer error from nearby current loops or ferromagnetic mounting hardware
  • Automotive transients and reverse-polarity events on the vehicle supply
  • Mixed-source power interaction between vehicle, USB, solar charger, and battery path
Validation
Success criteria
  • All core power and signal paths are fully integrated in the schematic.
  • User dimming and off-control paths are present and connected to the MCU.
  • PCB setup is sufficient to begin placement and prototype review.
  • ERC and review warnings are reduced to understood, intentional exceptions.
Planned checks
  • Schematic ERC review and targeted fixes
  • Power-path inspection of vehicle, USB, battery, and solar rails
  • Layout rule setup and component placement review
  • Prototype bring-up through SWD and display/sensor functional checks
Release-facing notes
Expected deliverables
  • Schematic
  • PCB layout
  • BOM
  • Manufacturing package
  • Bring-up and review notes
Special release notes
  • SWD shall use the standard 2x5 1.27 mm ARM pinout.
  • USB-C is power-only and uses sink-only CC configuration.
  • Magnetometer placement requires distance from inductor and high-current LED returns.
Change notes / open questions
Changes in this revision
  • Added dimmer ADC filtering and a standard SWD debug connector.
  • Added plan for automotive input fuse and reverse-polarity-safe front end.
  • Defined project scope and validation targets for prototype readiness.
Open questions
  • Final board dimensions and mounting-hole pattern for dashboard installation.
  • Final power-path interaction strategy between vehicle input, USB service input, battery, and solar charger.

  • Design Summary

  • Scope

  • System context

  • Requirements

  • Functional

  • Electrical

  • Mechanical / environmental

  • Key constraints

  • Dependencies and risks

  • Validation

  • Release-facing notes

  • Change notes / open questions