Before

FC_ESP32 Flight Controller

An ESP32-WROOM-32 based flight controller designed for 1S brushed quadcopters.

Features

• MCU: ESP32-WROOM-32 (8MB Flash)
• IMU: MPU-6500 (SPI interface)
• Motor Drivers: 4x AO3400 MOSFETs for brushed motors
• Optical Flow: UART interface for MTF-01P sensor (JST SH1.0 4-pin)
• Power: 1S LiPo input, TPS63001 Buck-Boost for 3.3V, TPS61070 Boost for 5V (USB/Optical flow)
• USB: USB-C connector with CH340C USB-to-UART bridge
• Expansion: I2C and UART1 breakout headers (2.54mm pitch)
• Battery Monitor: Built-in voltage divider for telemetry

Hardware Setup & Pinout

• Motors: J4, J5, J6, J7 pads (AO3400 driven)
• Optical Flow (J2): pin 1 GND, pin 2 +5V_FLOW, pin 3 ESP32 TX (GPIO17 → sensor RX), pin 4 ESP32 RX (GPIO16 ← sensor TX). Verify the actual sensor cable orientation.
• I2C Expansion (J8): VCC, GND, SDA (GPIO4), SCL (GPIO22)
• UART1 Expansion (J9): VCC, GND, TX (GPIO14), RX (GPIO32)
• Programming: CH340C DTR/RTS auto-download circuit; no physical Boot/Reset buttons are present in the generated BOM.

Current status

The subsequent datasheet review found B.Cu tracks inside the ESP32 antenna region, power-layout concerns and incomplete flight features despite clean ERC/DRC. See BAO_CAO_KIEM_TRA_MACH.md and validation/datasheet_audit/LOG_KIEM_TRA.md. The independent antenna check fails; do not interpret the routing checks below as proof that the design is ready to operate or manufacture.

PCB routing and final ERC/DRC/parity checks passed on 2026-09-14 (KiCad 10.0.6): zero violations and zero unconnected items. Motor solder pads moved 1.5 mm inward; J2 faces outward. See validation/FINAL_REVIEW.md and validation/final_3d.png. Not released for manufacturing or flight. Motor pitch is 66.8 mm, prop diameter 40 mm, board thickness 0.8 mm. Components are on the front; copper routing uses both layers. Firmware motor actuation is disabled by default; see firmware/README.md.

Reproducible hardware workflow

Use system Python with KiCad 10 pcbnew, sexpdata and Shapely installed. The generator replaces the working PCB and therefore discards its routing. Back up a routed board before regenerating.

/usr/bin/python3 tools/build_fc.py
/usr/bin/python3 tools/prepare_route.py
# Route the new FC_ESP32/FC_ESP32.dsn with Freerouting and save FC_ESP32.ses.
/usr/bin/python3 tools/import_route.py
/usr/bin/python3 tools/finish_copper.py
python3 tools/validate_fc.py

build_fc.py now includes clearance-preserving placement and updates the BOM and design coordinates. Session import validates placement before replacing copper. The legacy critical_routes.py and repair_connections.py contain assumptions from the older layout and are not part of this workflow.

On the current machine, prefix system-Python commands with PYTHONPATH=/home/pnt/miniconda3/lib/python3.14/site-packages. This path is environment-specific. Generation was verified in an isolated copy; all 72 component placements, orientations, values, footprints and nets matched.

The current SES predates the final repairs: do not import it onto the final PCB. validation/final_routed.kicad_pcb preserves the reviewed routing. tools/repair_c3_ground.py documents the deterministic final copper repair from validation/only_c3_ground_remaining.kicad_pcb to its candidate output.

Open FC_ESP32/FC_ESP32.kicad_pro for review. Validation records current ERC, DRC, netlist parity and source hashes in FC_ESP32/validation_summary.json and returns nonzero on errors. Reports do not replace current/thermal analysis or bench testing. gerbers/ contains stale outputs, not an approved release.