From 4ac775a13da5a9b026be2f652cc56b3c2e6a8116 Mon Sep 17 00:00:00 2001 From: Mikkeli Date: Mon, 12 Oct 2026 15:12:03 +0900 Subject: [PATCH] =?UTF-8?q?BOM:=20WT61=20being=20fitted=20on=20Dupont=20wi?= =?UTF-8?q?res;=20realign=20button=20optional=20(push=20button=20+=2010=20?= =?UTF-8?q?k=CE=A9)?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Co-Authored-By: Claude Opus 5.5 Claude-Session: https://claude.ai/code/session_01DDwfd6Ki8UfG4hK6W5YpJz --- docs/BOM.md | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) diff --git a/docs/BOM.md b/docs/BOM.md index 7bb06e5..c01a07f 100644 --- a/docs/BOM.md +++ b/docs/BOM.md @@ -98,7 +98,7 @@ type: reference ## WitMotion WT61 IMU -**Status: planned.** Moving from the smart-serow motorcycle unit, where an Arduino reads it; not fitted yet. +**Status: being fitted (2026-10-12)** on Dupont wires, moved from the smart-serow motorcycle unit, where an Arduino read it. Final mounting and connector to follow. | Field | Value | |-------|-------| @@ -120,7 +120,7 @@ type: reference | GND | 6 | | TX | 10 (UART1 RX) | | RX | 8 (UART1 TX), needed only to send config commands | -| *Realign button* | 7 (GPIO09, `PAC.06`) to ground on 9, with 10 kΩ pull-up to 3.3 V; planned, pin to confirm | +| *Realign button (optional)* | 7 (GPIO09, `PAC.06`) through the button to ground on 9; 10 kΩ from 7 to 3.3 V (pin 1). Pin to confirm | Everything sits in header pins 1–10, so one 2×5 connector can carry it. Pins 3/5 (I²C bus 7) carry the UPS monitor. @@ -144,7 +144,10 @@ Everything sits in header pins 1–10, so one 2×5 connector can carry it. Pins - **Output is low-pass filtered at 10 Hz** by default, even at 100 Hz output. Fine for vehicle motion, but it smooths out bumps and vibration. A gyro rate under 0.122 °/s reads as 0 (static threshold). Both are set only from WitMotion's PC software; there is no serial command for them. -- **Realign button (planned):** a press levels the frame to gravity (the mounting rotation, from averaged accelerometer readings) and sends +- **Realign button parts (optional, not fitted):** one momentary push button (normally open) and one 10 kΩ resistor. The resistor pulls + pin 7 up to 3.3 V, so the pin reads 1, and a press grounds it to 0. Realigning starts from the tablet app first; the button adds a way + that works without the tablet, triggering the same command. +- **Realign:** a press levels the frame to gravity (the mounting rotation, from averaged accelerometer readings) and sends `FF AA 52` to zero yaw. The result is stored on disk, not redone every drive. Refuse while moving (gyro or GPS speed); record raw data plus a realign event, so a bad alignment can be corrected afterwards. Align on level ground: a slope becomes part of the mount. - I²C mode (`FF AA 62`) exposes the raw MPU6050 only (no angles) and needs 4.7 kΩ pull-ups. Not used.