# ESP32-PICO-D4 (M5Stack Atom Lite) Port — Implementation Plan

> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.

**Goal:** Port the Sylvia Touch Relay project from ESP32-S3-Pico to ESP32-PICO-D4 (Atom Lite) with relay on G32, touch on G33 (pullup), SK6812 LED on G27, CDC-class USB detection in the Android app, and deploy via ADB wireless.

**Architecture:** Create side branch `esp32picod4` via git worktree. Replace platformio.ini S3 config with `m5stack-atom` board + FastLED library. Update pin definitions and LED code in main.cpp. Replace Android USB VID filter with CDC-ACM class filter. No DTR/RTS changes needed — the esp32-flash-lib handles it correctly.

**Tech Stack:** C++/Arduino (FastLED), PlatformIO (espressif32@6.7.0), Android/Kotlin (AGP 8.5.2, Gradle 8.14), ADB (wireless debugging)

---

### Task 1: Create sidebranch using git worktree

**Files:**
- Create: `.worktrees/esp32picod4/` (git worktree directory)

- [ ] **Step 1: Create and switch to sidebranch in worktree**

```bash
git worktree add -b esp32picod4 .worktrees/esp32picod4
```

- [ ] **Step 2: Verify branch is active**

```bash
git -C .worktrees/esp32picod4 branch --show-current
```
Expected: `esp32picod4`

---

### Task 2: Update PlatformIO configuration for PICO-D4

**Files:**
- Modify: `platformio.ini`

**Worktree path:** `.worktrees/esp32picod4/platformio.ini`

- [ ] **Step 1: Replace entire platformio.ini content**

```ini
[env:m5stack-atom]
platform = espressif32@6.7.0
board = m5stack-atom
framework = arduino
build_flags =
    -DESP32
    -DCORE_DEBUG_LEVEL=5
lib_deps =
    fastled/FastLED@^3.7.0
upload_port = /dev/ttyUSB0
upload_speed = 115200
```

- [ ] **Step 2: Verify m5stack-atom board exists in PlatformIO**

```bash
pio boards --json-output 2>/dev/null | python3 -c "import json,sys; boards=[b['id'] for b in json.load(sys.stdin) if 'm5stack-atom' in b['id']]; print('\n'.join(boards) if boards else 'NOT FOUND')"
```
Expected: `m5stack-atom` (or similar variant)

- [ ] **Step 3: Commit platformio.ini**

```bash
git -C .worktrees/esp32picod4 add platformio.ini
git -C .worktrees/esp32picod4 commit -m "feat: switch platformio config to m5stack-atom (ESP32-PICO-D4)"
```

---

### Task 3: Update firmware for Atom Lite (pins, LED, BLE name)

**Files:**
- Modify: `src/main.cpp`

**Worktree path:** `.worktrees/esp32picod4/src/main.cpp`

- [ ] **Step 1: Replace pin definitions (lines 10-12)**

Replace:
```cpp
#define SENSOR_PIN 38
#define RELAY_PIN  1
#define LED_PIN    46
```

With:
```cpp
#include <FastLED.h>

#define SENSOR_PIN 33
#define RELAY_PIN  32
#define LED_PIN    27
#define NUM_LEDS   1

CRGB leds[NUM_LEDS];
```

- [ ] **Step 2: Replace setup() LED init and blink code (lines 139-149)**

Replace:
```cpp
    pinMode(SENSOR_PIN, INPUT_PULLUP);
    pinMode(RELAY_PIN, OUTPUT);
    pinMode(LED_PIN, OUTPUT);

    for (int i = 0; i < 3; i++) {
        digitalWrite(LED_PIN, HIGH);
        delay(200);
        digitalWrite(LED_PIN, LOW);
        delay(200);
    }
    Serial.println("LED blink done, starting BLE...");
```

With:
```cpp
    pinMode(SENSOR_PIN, INPUT_PULLUP);
    pinMode(RELAY_PIN, OUTPUT);

    FastLED.addLeds<SK6812, LED_PIN, GRB>(leds, NUM_LEDS);
    FastLED.setBrightness(32);

    for (int i = 0; i < 3; i++) {
        leds[0] = CRGB::Green;
        FastLED.show();
        delay(200);
        leds[0] = CRGB::Black;
        FastLED.show();
        delay(200);
    }
    Serial.println("LED blink done, starting BLE...");
```

- [ ] **Step 3: Replace Serial banner and BLE device name**

Replace (line 125):
```cpp
    Serial.println("=== SylDa BLE Relay ===");
```

With:
```cpp
    Serial.println("=== Atom Lite BLE Relay ===");
```

Replace (line 151):
```cpp
    BLEDevice::init("SylDa_Server");
```

With:
```cpp
    BLEDevice::init("SyldaServer");
```

Replace (line 174):
```cpp
    Serial.println("BLE: advertising started as 'SylDa_Server'");
```

With:
```cpp
    Serial.println("BLE: advertising started as 'SyldaServer'");
```

- [ ] **Step 4: Verify main.cpp has no remaining S3-specific references**

```bash
grep -n "S3\|Atom Voice\|46\|G38\|G1\b" .worktrees/esp32picod4/src/main.cpp
```
Expected: no output (no matches)

- [ ] **Step 5: Commit main.cpp**

```bash
git -C .worktrees/esp32picod4 add src/main.cpp
git -C .worktrees/esp32picod4 commit -m "feat: port firmware to Atom Lite (G32 relais, G33 touch, G27 SK6812 LED, SyldaServer BLE)"
```

---

### Task 4: Update copy_firmware.sh for new environment name

**Files:**
- Modify: `tools/copy_firmware.sh`

**Worktree path:** `.worktrees/esp32picod4/tools/copy_firmware.sh`

- [ ] **Step 1: Change environment directory name (line 4)**

Replace:
```bash
BINARY_DIR="$(cd "$(dirname "$0")/.." && pwd)/.pio/build/s3lite-server"
```

With:
```bash
BINARY_DIR="$(cd "$(dirname "$0")/.." && pwd)/.pio/build/m5stack-atom"
```

- [ ] **Step 2: Commit**

```bash
git -C .worktrees/esp32picod4 add tools/copy_firmware.sh
git -C .worktrees/esp32picod4 commit -m "chore: update copy_firmware.sh for m5stack-atom environment"
```

---

### Task 5: Add CDC-class USB detection to UsbUtils.kt

**Files:**
- Modify: `android/app/src/main/java/com/eddy/atomrelay/UsbUtils.kt`

**Worktree path:** `.worktrees/esp32picod4/android/app/src/main/java/com/eddy/atomrelay/UsbUtils.kt`

- [ ] **Step 1: Add hasCdcDataInterface function**

After the `findBulkEndpoint` function (before the closing `}` of `object UsbUtils`), add:

```kotlin
    fun hasCdcDataInterface(device: UsbDevice): Boolean {
        for (i in 0 until device.interfaceCount) {
            if (device.getInterface(i).interfaceClass == CDC_DATA_INTERFACE_CLASS) {
                return true
            }
        }
        return false
    }
```

- [ ] **Step 2: Commit**

```bash
git -C .worktrees/esp32picod4 add android/app/src/main/java/com/eddy/atomrelay/UsbUtils.kt
git -C .worktrees/esp32picod4 commit -m "feat: add CDC-class USB detection for universal bridge support"
```

---

### Task 6: Replace VID filter with CDC-class filter in SettingsActivity.kt

**Files:**
- Modify: `android/app/src/main/java/com/eddy/atomrelay/SettingsActivity.kt`

**Worktree path:** `.worktrees/esp32picod4/android/app/src/main/java/com/eddy/atomrelay/SettingsActivity.kt`

- [ ] **Step 1: Remove ESP_VENDOR_ID constant (line 39)**

Delete:
```kotlin
        private const val ESP_VENDOR_ID = 0x303a
```

- [ ] **Step 2: Replace VID check in usbAttachedReceiver (line 67)**

Replace:
```kotlin
                if (device?.vendorId == ESP_VENDOR_ID) {
```

With:
```kotlin
                if (device != null && UsbUtils.hasCdcDataInterface(device)) {
```

- [ ] **Step 3: Replace VID check in usbPermissionReceiver (line 85)**

Replace:
```kotlin
                    val device = usbManager.deviceList.values.firstOrNull { it.vendorId == ESP_VENDOR_ID }
```

With:
```kotlin
                    val device = usbManager.deviceList.values.firstOrNull { UsbUtils.hasCdcDataInterface(it) }
```

- [ ] **Step 4: Replace VID check in usbDetachedReceiver (line 101)**

Replace:
```kotlin
                if (device?.vendorId == ESP_VENDOR_ID) {
```

With:
```kotlin
                if (device != null && UsbUtils.hasCdcDataInterface(device)) {
```

- [ ] **Step 5: Replace VID check in startKeyExchange (line 208)**

Replace:
```kotlin
        val device = usbManager.deviceList.values.firstOrNull { it.vendorId == ESP_VENDOR_ID }
```

With:
```kotlin
        val device = usbManager.deviceList.values.firstOrNull { UsbUtils.hasCdcDataInterface(it) }
```

- [ ] **Step 6: Replace VID check in startFlashing (line 256)**

Replace:
```kotlin
        val device = usbManager.deviceList.values.firstOrNull { it.vendorId == ESP_VENDOR_ID }
```

With:
```kotlin
        val device = usbManager.deviceList.values.firstOrNull { UsbUtils.hasCdcDataInterface(it) }
```

- [ ] **Step 7: Verify no remaining ESP_VENDOR_ID references**

```bash
grep -n "ESP_VENDOR_ID\|vendorId.*==" .worktrees/esp32picod4/android/app/src/main/java/com/eddy/atomrelay/SettingsActivity.kt
```
Expected: no output

- [ ] **Step 8: Commit**

```bash
git -C .worktrees/esp32picod4 add android/app/src/main/java/com/eddy/atomrelay/SettingsActivity.kt
git -C .worktrees/esp32picod4 commit -m "feat: replace USB VID filter with CDC-ACM class detection"
```

---

### Task 7: Compile firmware

**Files:** N/A (build artifacts in `.pio/build/m5stack-atom/`)

**Work tree path:** `.worktrees/esp32picod4/`

- [ ] **Step 1: Clean and compile**

```bash
pio run -d .worktrees/esp32picod4 -e m5stack-atom -t clean
pio run -d .worktrees/esp32picod4 -e m5stack-atom
```
Expected: `SUCCESS` at end of output

- [ ] **Step 2: Verify build output files**

```bash
ls -la .worktrees/esp32picod4/.pio/build/m5stack-atom/firmware.bin \
       .worktrees/esp32picod4/.pio/build/m5stack-atom/bootloader.bin \
       .worktrees/esp32picod4/.pio/build/m5stack-atom/partitions.bin
```
Expected: all 3 files exist with non-zero size

---

### Task 8: Copy firmware binaries to Android app assets

**Files:**
- Modify: `android/app/src/main/assets/firmware/` (destination)

**Worktree path:** `.worktrees/esp32picod4/`

- [ ] **Step 1: Run copy script**

```bash
bash .worktrees/esp32picod4/tools/copy_firmware.sh
```
Expected: lists 4 files (bootloader.bin, partitions.bin, firmware.bin, boot_app0.bin)

- [ ] **Step 2: Verify boot_app0.bin is also present**

```bash
ls -la .worktrees/esp32picod4/android/app/src/main/assets/firmware/boot_app0.bin
```
Expected: file exists

- [ ] **Step 3: Commit binary assets**

```bash
git -C .worktrees/esp32picod4 add android/app/src/main/assets/firmware/
git -C .worktrees/esp32picod4 commit -m "feat: add Atom Lite firmware binaries to Android assets"
```

---

### Task 9: Build Android APK

**Files:** N/A (build output `android/app/build/outputs/apk/debug/app-debug.apk`)

**Worktree path:** `.worktrees/esp32picod4/android/`

- [ ] **Step 1: Build debug APK**

```bash
JAVA_HOME=/home/linuxbrew/.linuxbrew/opt/openjdk@21/libexec ./gradlew assembleDebug
```
Expected: `BUILD SUCCESSFUL`

- [ ] **Step 2: Verify APK exists**

```bash
ls -la app/build/outputs/apk/debug/app-debug.apk
```
Expected: file exists with size > 1MB

---

### Task 10: Connect Android phone via ADB wireless

**Files:** N/A (ADB system tool)

- [ ] **Step 1: Load adb-wireless skill**

Use the `adb-wireless` skill to establish a wireless ADB connection to the Android phone.

- [ ] **Step 2: Verify ADB connection**

```bash
adb devices
```
Expected: `<ip>:5555` listed as `device`

---

### Task 11: Install APK on phone

**Files:** N/A (app deployment)

- [ ] **Step 1: Install APK**

```bash
adb install -r .worktrees/esp32picod4/android/app/build/outputs/apk/debug/app-debug.apk
```
Expected: `Success`

- [ ] **Step 2: Launch the app**

```bash
adb shell am start -n com.eddy.atomrelay/.MainActivity
```

---

### Task 12: Flash firmware to Atom Lite via Android app

**Files:** N/A (manual device action)

- [ ] **Step 1: Connect Atom Lite via USB-OTG to the phone**
- [ ] **Step 2: Open the app, tap settings gear → "Firmware Flashen"**
- [ ] **Step 3: If app doesn't auto-detect, unplug/replug the Atom Lite while the dialog is open**
- [ ] **Step 4: Wait for flash to complete (progress bar reaches 100%)**
- [ ] **Step 5: After flash, disconnect USB — the Atom Lite should reboot with green LED blink 3x**

---

### Task 13: Provision HMAC key via app

**Files:** N/A (manual device action)

- [ ] **Step 1: Reconnect Atom Lite via USB-OTG to phone (NOT in download mode — just power on normally)**
- [ ] **Step 2: Open app → Settings → "Sleutel Uitwisselen"**
- [ ] **Step 3: Wait for toast "Beveiligingssleutel gelezen" or provisioning**
- [ ] **Step 4: If key was newly generated, verify Serial monitor shows "HMAC key stored in NVS"**

---

### Task 14: Verify BLE connection and relay control

**Files:** N/A (manual verification)

- [ ] **Step 1: Power on the Atom Lite (with relay and touch sensor connected)**
- [ ] **Step 2: Open the Android app — verify it auto-connects to "SyldaServer"**
- [ ] **Step 3: Verify status shows "Connected"**
- [ ] **Step 4: Hold HOLD button — verify relay activates (click or multimeter)**
- [ ] **Step 5: Release — verify relay deactivates**
- [ ] **Step 6: Touch sensor on G33 — verify relay also activates**

---

## Self-Review

**1. Spec coverage:**
- Sidebranch `esp32picod4`: Task 1 ✓
- Compile for ESP32-PICO-D4: Task 2 ✓
- Pins G32/G33/G27: Task 3 ✓
- SK6812 LED with FastLED: Task 3 ✓
- BLE name "SyldaServer": Task 3 ✓
- CDC-class USB detection: Tasks 5, 6 ✓
- DTR/RTS no changes: Confirmed in research, no task needed ✓
- Bundle binary with Android app: Task 8 ✓
- Build APK: Task 9 ✓
- ADB wireless deploy: Tasks 10, 11 ✓
- Flash + provision + test: Tasks 12-14 ✓

**2. Placeholder scan:** No TBD, TODO, or incomplete sections. All commands are concrete with expected output.

**3. Type consistency:** `hasCdcDataInterface(device: UsbDevice): Boolean` defined in Task 5, used consistently in Task 6 with `UsbUtils.hasCdcDataInterface(device/it)`.