next: external sensors

Hardware upgrade

ā† home

Phone-only has hit its ceiling: there's no absolute heading reference, so the slip estimate drifts and we keep patching the symptoms. A small Raspberry Pi reading a fused IMU + 10 Hz GPS (streamed to the phone over Wi-Fi) fixes that at the source ā€” and opens up a lot more.

what it unlocks
šŸ§­
Trustworthy slip ā€” finally
The BNO085 reports absolute heading directly, so Ļˆ stops drifting. The Ā±180Ā° runaway, the wrong-pointing arrow, the band-aids ā€” all gone at the source. Slip becomes ground truth, not an estimate we keep patching.
šŸ›°
10Ɨ sharper line
10 Hz GPS (vs the phone's 1 Hz) means the map line, course auto-detect, named zones, and slide boundaries get an order of magnitude more precise ā€” corner-by-corner scoring you can actually trust.
āš™
What the car is doing
OBD/CAN adds RPM, throttle, and wheel speed. Wheel-speed vs GPS-speed = wheelspin / longitudinal slip. Throttle trace = on/off-throttle through each corner. The inputs behind the slide, not just the slide.
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Fuel for the learning-engine
Clean, high-rate, multi-channel data is the training signal. With it YAW can learn his per-corner baseline, give anticipatory coaching, and drive a real progression plan toward FD ProSpec ā€” the moonshot.
the build ā€” start here (~$170, works on any car)
Raspberry Pi 42 GB (4 GB fine) Ā· $45
Full USB ports + Wi-Fi to stream to the phone. Sweet spot ā€” Pi 5 overkill, Zero 2 W needs adapters.
microSD 32 GBA1/A2, SanDisk Ā· $8
OS + on-board CSV log backup.
USB-C power bank10,000 mAh Ā· 5V/3A Ā· $20
Clean power; isolates the Pi from car electrical noise and survives engine cranking.
ā˜… BNO085 9-DoF IMUAdafruit Ā· STEMMA QT Ā· $20
Absolute fused heading (no gyro drift) + 100 Hz motion ā€” fixes the slip/heading problem at the source.
Qwiic cable + SHIMno soldering Ā· $5
IĀ²C connection for the IMU.
ā˜… u-blox NEO-M9N GPS10 Hz Ā· USB-C Ā· w/ antenna Ā· $70
10Ɨ the line & course resolution of phone GPS ā€” sharper zones + slip fusion.
Case, fan, mountsvelcro, zip ties Ā· $25
Keep it cool and rigidly mounted.
before ordering OBD ā€” check the car

RPM / throttle / wheel-speed need the ECU to cooperate. If the S14 runs a stock-ish ECU, an OBDLink SX (USB, ~$30) works. If it has an aftermarket ECU (Haltech / Link / MaxxECU ā€” common in drift builds), standard OBD-II usually won't respond ā€” you'd tap the ECU's CAN stream with a PiCAN2 HAT (~$50) instead. Confirm what the car exposes before buying that piece. The IMU + GPS work on any car regardless.

priority
  1. Now: Pi 4 + power bank + SD + BNO085 IMU + NEO-M9N GPS (~$170) ā€” fixes slip/heading on any car.
  2. Then: OBD or CAN, once you confirm the ECU.
  3. Later: steering-angle encoder, brake-pressure sensor, tire-temp IR Ɨ4, Pi camera.
šŸ›° Connect (when it's built)ā† Home

Full wiring + setup lives in the repo under pi/ (BOM.md, README.md, install.sh). When the parts arrive, install.sh sets it up and the phone connects via Settings ā†’ relay URL.