Documentation Index Fetch the complete documentation index at: https://docs.elata.bio/llms.txt
Use this file to discover all available pages before exploring further.
Crate Architecture The firmware is a Rust workspace split into five crates with strict layering — no circular dependencies.
Crate Owns Depends On eeg_types Packet, ChannelId, AdcConfig, error enums— sensors Register maps, low-level SPI/I2C for a single chip eeg_types boards Glue that unites one or more chips into a PCB driver (impl EegDriver) sensors, eeg_types pipeline DSP graph, processing stages, sinks eeg_types daemon CLI, config, picks a board driver and pumps packets into the pipeline boards, pipeline, eeg_types
The daemon is the only binary crate. Everything else is a library.
Plugin System Plugins are event-driven and run in parallel across CPU cores. Each plugin is a separate Rust crate in the plugins/ directory.
Writing a Plugin Every plugin implements the EegPlugin trait:
#[async_trait] impl EegPlugin for MyPlugin { fn name ( & self ) -> & ' static str { "my_plugin" } fn clone_box ( & self ) -> Box < dyn EegPlugin > { Box :: new ( self . clone ()) } async fn run ( & mut self , bus : Arc < dyn EventBus >, mut receiver : broadcast :: Receiver < SensorEvent >, shutdown_token : CancellationToken , ) -> Result <()> { loop { tokio :: select! { biased ; _ = shutdown_token . cancelled () => break , Ok ( event ) = receiver . recv () => { // process event, then broadcast results back to bus } } } Ok (()) } }
Plugins can optionally declare an event_filter to subscribe only to relevant event types, avoiding unnecessary wake-ups.
Included Plugins Plugin Purpose basic_voltage_filterVoltage scaling and filtering brain_waves_fftFFT spectral decomposition with browser UI csv_recorderRecord sessions to CSV files
WebSocket API The daemon exposes a centralized WebSocket endpoint for real-time data streaming with a topic-based pub/sub model.
Endpoint: ws://localhost:9000/ws/dataSubscribe to a Topic { "type" : "subscribe" , "topic" : "eeg_voltage" , "epoch" : 1 }
Unsubscribe { "type" : "unsubscribe" , "topic" : "eeg_voltage" }
Data frames are binary (RtPacket format) for high-performance streaming. A single client can hold multiple topic subscriptions simultaneously.
Control Plane (REST + SSE) In addition to the WebSocket data plane, the daemon provides HTTP endpoints on the same port:
Endpoint Method Purpose /api/pipelinesGET List available pipeline definitions /api/pipelines/{id}/startPOST Start a pipeline /api/pipeline/stopPOST Stop the running pipeline /api/stateGET Current runtime configuration snapshot /api/eventsGET SSE stream of state updates /api/pipelines/{id}/controlPOST Send runtime commands (e.g. SetParameter)
Board Configurations V1 — Single ADS1299 One ADS1299 EVM connected directly to the Pi 5 via SPI. Provides 8 channels with buffered reference (SRB1) and fixed internal bias drive.
SPI Signal ADS1299 Pin (J3) Pi 5 Pin CS Pin 1 Pin 24 (CE0) SCLK Pin 3 Pin 23 MOSI (DIN) Pin 11 Pin 19 MISO (DOUT) Pin 13 Pin 21 DRDY Pin 15 Pin 22 (GPIO25)
V2 — Four Synchronized ADS1299 Boards Star topology with one master board and three secondaries sharing clock, MOSI, SCLK, and MISO. Each board has a dedicated chip-select and DRDY line. Only the master board (Board 0) drives the bias electrode.
Signal Pi 5 Pin Notes CS_A (Board 0) Pin 24 (CE0) Hardware CS CS_B (Board 1) Pin 26 (CE1) Hardware CS CS_C (Board 2) Pin 29 (GPIO5) Software CS CS_D (Board 3) Pin 31 (GPIO6) Software CS START (all boards) Pin 15 (GPIO22) Sync pulse DRDY (Board 0) Pin 22 (GPIO25) Falling-edge interrupt
Next
EEG Overview Hardware BOM and quickstart
SDK — eeg-web-ble Connect to EEG headbands over Web Bluetooth
