# DoorCounter

Retail door traffic counter using M5Stack TimerCamera-F (ESP32 + OV3660). Counts entries/exits via overhead camera CV, passively scans BLE foot traffic, and reports hourly to `logs.research.bike`.

## Hardware

- **Device**: M5Stack TimerCamera-F (ESP32-S, OV3660, PSRAM, WiFi/BLE)
- **Mount**: Overhead, camera pointing straight down, centered above doorway
- **Power**: USB (any phone charger)

## Firmware

Built with PlatformIO. Target: `timercam`.

```bash
cd firmware
pio run -t upload --upload-port /dev/ttyUSB0
```

### What it does

| Module | Behavior |
|--------|----------|
| CV pipeline | 5 fps, 96×96 grayscale, blob tracking, directional traversal count (origin→destination, once per track) with per-direction cooldown safety net |
| Detection LED | Single blink on entry, double blink on exit (preserves upload/no-WiFi status LED) |
| BLE scanner | Continuous passive scan; deinits during hourly upload to free heap |
| Reporter | Hourly HMAC-signed POST; 60s boot report for fast connectivity check |
| Provisioning | Captive portal AP on first boot for WiFi setup |
| OTA | Arduino OTA; operator push via `ota_push.py` |

### Reporting intervals

- **First report**: 60 seconds after NTP sync (connectivity check)
- **Subsequent reports**: every 3600 seconds

### Directional counting

Each tracked blob fires at most **one** event over its lifetime, and only
when it has genuinely traversed the frame — specifically, when its spawn
position and current position are both at least `CV_TRAVERSAL_MARGIN_PX`
(14 px ≈ 15% of the 96×96 frame) from the line, and on opposite sides.

- Top half → bottom half traversal = **entry**
- Bottom half → top half traversal = **exit**

A blob that appears near the line and wobbles across it does not count
(both positions are within the margin band). A blob that fully traverses
then reverses under the same track also does not double-count (the track
is flagged `counted`). If tracking churns — the track dies mid-traversal
and respawns on the other side — a new track with a new spawn on the
crossed side is the normal path to a correct count.

See `firmware/lib/cv/cv.h` for margin and `cv.cpp` for the crossing logic.

### Crossing cooldown (safety net)

On top of directional counting, each direction enforces a cooldown between
counted events. Default: `CV_CROSSING_COOLDOWN_FRAMES = 5` (≈0.8s at 5 fps).
Entries and exits maintain separate cooldowns, so a real entry immediately
followed by a real exit still counts both.

## Operator Setup

### 1. Flash firmware

```bash
cd firmware
pio run -t upload --upload-port /dev/ttyUSB0
```

### 2. Provision device identity

```bash
python tools/flash_device.py \
  --port /dev/ttyUSB0 \
  --device-id dc-0042 \
  --location-id retailer-123 \
  --hmac-secret <32-byte-hex> \
  --wifi-ssid "StoreWiFi" \
  --wifi-password "secret"
```

WiFi credentials are optional — if omitted, device starts captive portal on boot.

> **Re-provision after firmware uploads.** Flashing firmware via
> `pio run -t upload` may clear the NVS partition on this board. If the device
> boots into a ~1 Hz LED blink (the "not provisioned" fatal state) after a
> firmware update, re-run `flash_device.py` with the same credentials. See
> [Troubleshooting](#troubleshooting).

### 3. OTA updates

```bash
python tools/ota_push.py \
  --host dc-0042.local \
  --firmware firmware/.pio/build/timercam/firmware.bin
```

## End User Setup

1. Mount device overhead, camera pointing straight down
2. Plug into USB power
3. Connect phone to `DoorCounter-Setup` WiFi
4. Browser opens automatically → enter store WiFi password → done

**LED indicators**: Red = no WiFi · Blue = counting · Yellow = uploading · Brief flash (×1) on entry · Brief flash (×2) on exit

## API

Endpoint: `http://logs.research.bike`

| Endpoint | Data |
|----------|------|
| `POST /api/v1/camera/events/batch` | Hourly entry/exit counts |
| `POST /api/v1/events/batch` | Hourly BLE proximity records |
| `POST /api/v1/heartbeat` | Device health (uptime, RSSI, pending records) |

All requests are HMAC-SHA256 signed. See [design spec](docs/superpowers/specs/2026-04-13-door-counter-design.md) for full API shapes and auth scheme.

## Project Structure

```
DoorCounter/
├── firmware/
│   ├── platformio.ini
│   ├── lib/
│   │   ├── cv/            — CV pipeline (blob tracking, line cross, cooldown)
│   │   └── hmac/          — HMAC-SHA256 signing library
│   └── src/
│       ├── main.cpp       — FreeRTOS tasks, boot sequence
│       ├── config.*       — NVS read/write
│       ├── provisioning.* — captive portal
│       ├── camera.*       — frame capture + CV pipeline
│       ├── ble_scanner.*  — BLE passive scan
│       └── reporter.*     — hourly batch POST + local buffer
├── tools/
│   ├── flash_device.py    — NVS provisioning script
│   ├── ota_push.py        — OTA push script
│   └── serial_monitor.py  — reset + read serial with timestamps (diagnostic)
├── docs/
│   ├── server-prompt-crossing-cooldown.md — server-side coordination notes
│   └── superpowers/specs/2026-04-13-door-counter-design.md
└── server/                — API server (separate deployment)
```

## Troubleshooting

| Symptom | Likely cause | Remedy |
|---------|--------------|--------|
| ~1 Hz LED blink after boot, no serial beyond `esp_core_dump_flash: No core dump partition found!` | NVS missing `device_id` / `location_id` / `hmac_secret`. Commonly triggered by a firmware upload wiping NVS. | Re-run `flash_device.py` with the device's known credentials. |
| Device stays on `DoorCounter-Setup` AP instead of joining customer WiFi | SSID/password in NVS wrong, or network out of range. | Connect phone to `DoorCounter-Setup` → captive portal → re-enter WiFi. Or reflash NVS with correct `--wifi-ssid` / `--wifi-password`. |
| No entries/exits counted for a known-walking doorway | WiFi captive portal still up (camera task starts only after connect); or camera blocked/unfocused. | Check LED: solid on = booting/uploading, off = counting. Run `serial_monitor.py` to see `[CV] entry/exit` log lines. |

Capture a boot log with timestamps:

```bash
python tools/serial_monitor.py --port /dev/ttyUSB0 --reset --timestamp --seconds 30
```