MTZ Shift Detector — ESP32‑S2 (LOLIN S2 mini) v1.1
Two AS5600 angle sensors (one per axis) -> classify tractor gear position Adds grid-based shifter model with range latch (I/II) and hysteresis. Manual override page allows forcing gear code for remote testing.
Exposes Modbus TCP holding registers and a minimal Wi‑Fi HTTP UI for calibration, status, manual override, grid calibration, and network settings.
─────────────────────────────────────────────────────────────────────────── Hardware notes (quick schematic snippet) ─────────────────────────────────────────────────────────────────────────── • MCU: LOLIN S2 mini (ESP32‑S2). Power via USB‑C 5 V; on‑board 3V3 LDO. • Sensors: 2 × AS5600 (address 0x36 each) on SEPARATE I²C controllers. I²C‑X: SDA=GPIO33, SCL=GPIO35 I²C‑Y: SDA=GPIO9, SCL=GPIO11 (Remappable if layout requires. Avoid GPIO19/20 — USB D−/D+.) • Pull‑ups: 2.2–4.7 kΩ from SDA/SCL to 3V3 on EACH bus near the MCU. • Decoupling: each AS5600 gets 100 nF + 1 µF close to VDD. • Magnets: 6–8 mm diametric, 2–3 mm thick; air‑gap 1.0–2.5 mm; align axes. • ESD/EMI: optional ESD diodes to 3V3/GND on SDA/SCL; twist SDA/SCL pairs. • Power: AS5600 VDD = 3V3. All logic is 3.3 V only.
─────────────────────────────────────────────────────────────────────────── Modbus TCP register map (all Holding, big‑endian 16‑bit; index=Hreg-40001) ─────────────────────────────────────────────────────────────────────────── 40001 RAW_X u16 (0..4095) [index 0] 40002 RAW_Y u16 1 40003 FILT_X u16 2 40004 FILT_Y u16 3 40005 GEAR_CODE u16 0=N, 1..9, 101=R1, 102=R2, 65535=unknown 4 40006 STATUS u16 b0:calib b1:magOK_X b2:magOK_Y b3:selector b4:wifiUp b5:fault_X b6:fault_Y b7:manual b8:gridMode 40007 AGC_X u16 6 40008 MAG_X u16 7 40009 AGC_Y u16 8 40010 MAG_Y u16 9 40011 UPTIME_LO u16 10 40012 UPTIME_HI u16 11 40013 FW_VER u16 0x0100 = v1.0.0 12 40014 ERROR u16 last error code 13 40015 OVERRIDE_CTRL u16 bit0: enable 14 40016 OVERRIDE_CODE u16 code (0..,101,102,65535) 15 40017 RANGE u16 0=unknown,1=I,2=II 16 40018 GRID_NODE u16 enum id of grid 17
Discrete Inputs (1xxxx) — one-hot mirror of GEAR_CODE for compatibility ─────────────────────────────────────────────────────────────────────────── DI0 (10001) = Neutral DI1 (10002) = Gear 1 DI2 (10003) = Gear 2 DI3 (10004) = Gear 3 DI4 (10005) = Gear 4 DI5 (10006) = Gear 5 DI6 (10007) = Gear 6 DI7 (10008) = Gear 7 DI8 (10009) = Gear 8 DI9 (10010) = Gear 9 DI20 (10021) = Reverse 1 (R1) DI21 (10022) = Reverse 2 (R2)
HTTP UI ─────────────────────────────────────────────────────────────────────────── • / : index links • /status : JSON live data • /log : text ring‑buffer log of gear changes • /grid : GRID calibration (selectors, N, six grid nodes) -> /api/grid/record?slot=SEL_I|SEL_II|X±1_Y±1|X±1_Y0|N -> /api/grid/save | /api/grid/load | /api/grid/clear : GRID calibration (selectors, N, six grid nodes) -> /api/grid/record?slot=SEL_I|SEL_II|X±1_Y±1|X±1_Y0|N -> /api/grid/save | /api/grid/load | /api/grid/clear • /manual : manual override enable/disable and force gear -> /api/manual/enable?on=0|1 -> /api/manual/set?code=0..9|101|102|65535 • /net : set Wi‑Fi password for SSID "Tracktor" and reboot
Build: Arduino IDE (ESP32 board core), select LOLIN S2 mini (ESP32‑S2). Libraries: built‑in WiFi, WebServer; install "Modbus-ESP8266".