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# CLAUDE.md
Guidance for Claude Code (claude.ai/code) working in this repo.
## Running the app
```bash
python main.py
```
No build step. Simulation mode default (no hardware needed).
## Dependencies
```bash
pip install PyQt6 pyqtgraph numpy pyserial
pip install nidaqmx # optional — only for real NI hardware
```
## Architecture
### Data flow
```
Hardware / Simulation
↓
api_layers/ ArduinoLayer, NidaqmxLayer — low-level I/O, background threads
↓
devices/ BaseDevice subclasses — wrap api_layers, expose read_channels() / write_channel()
↓
core/acquisition.py AcquisitionEngine — polls devices at 100 ms, fills ChannelBuffers, emits new_data signal
↓
core/signal_processor.py SignalProcessor — filters + derived channels, re-emits processed_data
↓
ui/strip_chart.py StripChartWidget — consumes processed_data, renders via pyqtgraph
```
Control widgets (left panel) go other direction: UI → `ControlWidget._write()` → `DeviceRegistry.get_instance()` → `device.write_channel()` → api_layer.
### Key design patterns
**Shared serial port** — `api_layers/port_registry.py` holds module-level `port_registry` singleton. Multiple devices sharing one Arduino (e.g. `AnalogInputDevice` + `DigitalIODevice` on same port) both call `port_registry.get_layer(port, baud)`, get same `ArduinoLayer` instance. Never construct `ArduinoLayer` directly in device code.
**Device auto-discovery** — `DeviceRegistry._discover()` scans `devices/` with `pkgutil`, imports every module, registers any class subclassing `BaseDevice`. New device type = drop file in `devices/`, no registration needed.
**Backend switching at runtime** — `AnalogInputDevice` and `DigitalIODevice` both have `switch_backend(backend, simulate, ...)` — disconnects, reconfigures, reconnects without restart. Called from "Apply & Reconnect" in config dialog.
**Profile persistence** — `core/profile.py` serialises full operator state (controls, plot layout, signal pipelines, derived channels) to `.labdaq` JSON files. `ProfileManager` handles save/load.
### Directory map
| Path | Purpose |
|------|---------|
| `api_layers/arduino_layer.py` | Serial protocol + simulation; `ARDUINO_FIRMWARE` string is the uploadable sketch |
| `api_layers/nidaqmx_layer.py` | NI-DAQmx wrapper with simulation fallback |
| `api_layers/port_registry.py` | Shared `ArduinoLayer` singleton per (port, baud) |
| `devices/base_device.py` | `BaseDevice`, `ChannelConfig`, `DeviceInfo`, `DeviceStatus` |
| `devices/analog_input.py` | Analog input — NI or Arduino backend |
| `devices/digital_io.py` | Digital I/O — NI or Arduino backend |
| `devices/serial_device.py` | Generic UART device |
| `core/acquisition.py` | `AcquisitionEngine` + `ChannelBuffer` |
| `core/signal_processor.py` | Filter chain + derived/virtual channels |
| `core/profile.py` | `.labdaq` profile save/load |
| `ui/main_window.py` | Top-level window, toolbar, demo device init |
| `ui/control_panel.py` | Left panel output widgets (`OnOffSwitch`, `MotorControl`, etc.) |
| `ui/strip_chart.py` | Live pyqtgraph chart, config-driven by `LayoutConfig` |
| `ui/windows/` | Floating tool windows (Devices, Signals, Plot, Settings) |
| `ui/style_dark.qss` / `style_light.qss` | Full app theme |
### Arduino firmware
Firmware embedded as `ARDUINO_FIRMWARE` in `api_layers/arduino_layer.py`. When editing: set `N_DIG_OUT` to match digital output pins in use (default 0 — leaves pins in INPUT mode, causes inverted write behaviour). Upload via Arduino IDE.
Serial protocol: `A0:3.14,D2:1\n` stream from Arduino; `W:D7:1\n` / `P:D9:128\n` commands from PC.
### Adding a new device type
1. Subclass `BaseDevice` in new file under `devices/`
2. Implement: `connect()`, `disconnect()`, `read_channels() → Dict[str, float]`, `write_channel(channel_id, value) → bool`, `get_config_widget() → QWidget`
3. Include `switch_backend()` if device supports runtime reconfiguration
4. `DeviceRegistry` discovers it automatically on next run
|
