ESP32 HeadTracker – Skyzone → AtomRC (ELRS / ESP-NOW) Overview Transforms Skyzone head-tracking PPM into PAN/TILT commands sent through ELRS (CRSF) or ESP-NOW, then drives an AtomRC gimbal using a second ESP32. Diagram: Skyzone HT (PPM)

│
▼
┌───────────────┐        CRSF/ELRS         ┌───────────────┐
│   ESP32 TX    │     ──────────────▶     │   ESP32 RX    │
│ (Goggles side)│                          │ (Gimbal side) │
└───────────────┘        ESP-NOW fallback  └───────────────┘
│                                                  │
└── PWM bench (optional)                           └── Servos PAN/TILT

Pin Mapping

TX (Goggles)

PPM input (Skyzone) → GPIO25 Mode switch A → GPIO32 Mode switch B → GPIO33 Button / Joystick UP → GPIO26 Pan servo (bench) → GPIO18 Tilt servo (bench) → GPIO19 ELRS CRSF TX → module → GPIO17

RX (Drone)

CRSF UART RX → GPIO16 ESP-NOW (WiFi STA) → internal Pan servo → GPIO18 Tilt servo → GPIO19

3-Position Output Switch (TX)

A=LOW, B=HIGH → Wired PWM (bench) A=HIGH, B=LOW → CRSF / ELRS (normal flight) A=HIGH, B=HIGH → ESP-NOW

Button Logic (TX – GPIO26)

Hold button: camera forced to center Release button: recenter (new offsets) Double click: NORMAL → RACING → TILT-ONLY → NORMAL → ...

Mode CAMERA MOUVEMENTS:

NORMAL : Pan+Tilt follow head tracker RACING : Pan=90°, Tilt=+20° up TILT-ONLY : Pan locked at activation, Tilt follows PPM

Angle Conventions

PAN: 0° = left 90° = center 180° = right

TILT: smaller value = up (sky) 90° = horizon larger value = down (ground)

========== Data Flow

1. MODE COMM: CRSF / ELRS Path (priority) ========================================= TX: PPM → filtering → degrees → CRSF RC frame → ELRS module RX: ELRS RX → CRSF RC frame → degrees → smoothing → servos

2. MODE COMM : ESP-NOW (WIFI) Fallback ====================================== TX: filtered degrees → ControlPacket → ESP-NOW send RX: ESP-NOW packet → checksum → targetPan/targetTilt → smoothing → servos

Priority: CRSF alive → use CRSF else if ESP-NOW alive → use ESP-NOW else → auto-center

Filtering (TX)

error = |target – current|

If error small: TARGEt GOGGLE POSITION IS CLOSE FROM CAMERA CURRENt POSITION gain = low update rate = slow

If error large: TARGET GOGGE POSITION IS FAR FROM CAMERA CURRENt POSITION gain = high update rate = fast

WHAT IS CLOSE? WHAT IS FAR?

PAN range: 2°→10° (gain 0.04 → 1.0) TILT range: 2°→5° (gain 0.01 → 1.0)

ControlPacket Format (ESP-NOW) struct { uint16 header = 0xA55A uint16 pan = filtered pan deg uint16 tilt = filtered tilt deg uint16 flags = bit0 = PPM valid uint16 checksum = XOR(header,pan,tilt,flags,0x55AA) }

Useful Serial Commands in CLI center = recenter debug = dump status test = servo sweep test (local) deadband X = set deadband (TX only)

Wiring ASCII

LINK : Skyzone → ESP32 TX : Skyzone HT PPM ─────────> GPIO25 Skyzone GND ────────────> ESP32 GND

LINK : ESP32 TX → ELRS GPIO17 (TX) → ELRS module RX GND shared

LINK : ESP32 RX → Servos GPIO18 → Pan servo GPIO19 → Tilt servo 5V/GND → from BEC

ESP-NOW MAC Setup :  x

 (FOR ESPNOW WIFI LINK WE USe board MAC adresse

1. Write this scrit in Arduino IDE and run. #include <WiFi.h> WiFi.mode(WIFI_STA); Serial.println(WiFi.macAddress());

2. Then Copy RX MAC into TX: const uint8_t ESP_NOW_PEER_MAC[6] = {xx,xx,xx,xx,xx,xx};

Files Summary HeadTracker_ESP32_TX_Gemini_by_ymanda.ino → goggles-side logic HeadTracker_ESP32_RX_Gemini_by_ymanda.ino → gimbal-side logic README.md → this document Auteur: Yannick Mandaba (Ymanda) Last edit: 27 NOV 2025