Crate ados_sensorhub

Expand description

§ados-sensorhub

Sensor hub wire protocol: COBS framing, CRC-16/CCITT-FALSE and fixed-layout IMU, barometer, magnetometer, trigger, PPS and GNSS packets. no_std, no allocation.

A sensor hub is a small microcontroller that timestamps IMU samples, camera triggers and PPS edges on one clock and streams them to a companion computer over USB or a UART. This crate is the wire format both ends share: the same code encodes on the microcontroller and decodes on the host. Reach for it when you build either side of such a link and want byte-exact packets, framing that resynchronises after line noise, and no heap.

use ados_sensorhub::{
    decode_frame, encode_frame, Deframer, ImuBatch, ImuSample, ImuSamples, Packet, Push,
    MAX_FRAME, MAX_RAW,
};

// Encode two IMU samples taken 1 ms apart as one wire frame.
let samples = [
    ImuSample { gyro: [1, -2, 3], accel: [0, 0, 2048], temp: 3150 },
    ImuSample { gyro: [2, -1, 4], accel: [1, 0, 2049], temp: 3151 },
];
let pkt = Packet::ImuBatch(ImuBatch {
    t0_ns: 5_000_000,
    dt_ns: 1_000_000,
    imu_id: 0,
    flags: 0,
    seq0: 100,
    samples: ImuSamples::Typed(&samples),
});
let mut scratch = [0u8; MAX_RAW];
let mut wire = [0u8; MAX_FRAME];
let n = encode_frame(&pkt, &mut scratch, &mut wire).unwrap();

// The receiver splits the byte stream on 0x00 and decodes each block.
let mut deframer = Deframer::<MAX_FRAME>::new();
let mut buf = [0u8; MAX_RAW];
let mut decoded = 0;
for &b in &wire[..n] {
    if let Push::Block(block) = deframer.push(b) {
        let Packet::ImuBatch(batch) = decode_frame(block, &mut buf).unwrap() else {
            panic!("expected an IMU batch");
        };
        assert_eq!(batch.samples.get(1), Some(samples[1]));
        assert_eq!(batch.sample_t_ns(1), 6_000_000);
        decoded += 1;
    }
}
assert_eq!(decoded, 1);

§Highlights

#![no_std], no allocation: every buffer is caller-owned, sized by the MAX_RAW and MAX_FRAME constants.
Zero required dependencies; serde derives on the owned packet structs are opt-in.
#![forbid(unsafe_code)].
Decoding borrows variable-length payloads (IMU samples, GNSS and RTCM bytes) straight from the decode buffer, with no copy.
Unknown packet types decode to Packet::Unknown instead of failing, so a newer hub does not break an older host.
Round-trip, framing and malformed-input tests, including proptest round trips.

§How it works

Every packet travels as one frame:

wire  := COBS(raw) 0x00
raw   := type:u8  len:u16le  payload[len]  crc:u16le
crc   := CRC-16/CCITT-FALSE over type, len and payload

COBS (Consistent Overhead Byte Stuffing) removes every 0x00 from the raw frame, so 0x00 can only appear as the delimiter. A receiver that starts mid-stream, or loses bytes, recovers at the next delimiter. Payloads are at most MAX_PAYLOAD (1024) bytes; multi-byte fields are little-endian, reserved fields are written as zero and ignored on receive, and every t_ns is hub time.

encode_frame writes one delimited wire frame; encode_raw writes only the raw frame.
Deframer splits a byte stream on 0x00 into COBS blocks, one byte at a time. A block longer than its buffer is dropped up to the next delimiter and reported as Push::Overflow.
decode_frame unstuffs one block and parses it; decode_raw parses a raw frame. Both check the length and the CRC before touching the payload.
cobs and crc are usable on their own.

Packet types:

Type	Packet	Payload
`0x01`	`Hello`	40 bytes: protocol and firmware version, board ID, capability bits, MCU UID, board name
`0x10`	`ImuBatch`	20-byte header plus 1 to 64 samples of 14 bytes (raw gyro, accel, temperature)
`0x11`	`Baro`	20 bytes: pressure and temperature
`0x12`	`Mag`	24 bytes: field in microtesla
`0x20`	`Trigger`	28 bytes: camera trigger sequence, exposure start, mid-exposure time and length
`0x30`	`Pps`	24 bytes: PPS edge time, lock state, phase error, frequency correction
`0x40`	`GnssRaw`	10-byte header plus up to 1014 receiver bytes
`0x41`	`RtcmIn`	2-byte header plus up to 1022 correction bytes
`0x50`	`Config`	16 bytes: trigger rate and mode, IMU rate and batch size, outputs, heater target
`0x60`	`Health`	40 bytes: uptime, temperatures, input voltage, drop and error counters

Raw IMU counts convert with GYRO_LSB_RAD_S (±2000 dps full scale) and ACCEL_LSB_M_S2 (±16 g full scale).

§Cargo features

Feature	Default	What it enables
`serde`	no	`Serialize`/`Deserialize` on the owned packet structs

§Part of ADOS

Used in production by the ADOS Drone Agent, the onboard software of the ADOS software-defined drone platform. All ADOS crates · Docs · Discord

§Other ADOS crates

Platform (versioned with the ADOS Drone Agent)

Crate	What it does	Docs
`ados-protocol`	Wire contracts of the ADOS Drone Agent: IPC framing, plugin RPC envelope, capability tokens and the vision frame bus.	docs.rs
`ados-sdk`	Write Rust plugins for the ADOS Drone Agent: IPC client, plugin context, driver traits and lifecycle runner.	docs.rs
`ados-vision`	Single-object visual tracker: Kalman motion model, appearance re-identification and YOLOv8 head decoding.	docs.rs
`ados-gpio`	Drive status buzzers and LEDs on Linux GPIO lines, with bounded software-PWM beep patterns.	docs.rs
`ados-hal-probe`	Find out what a board’s hardware can really do by probing it, plus bundled board profiles.	docs.rs

Standalone

Crate	What it does	Docs
`ados-offload`	Choose where perception runs (onboard, offloaded or hybrid) and hold the vehicle when results go stale.	docs.rs
`ados-macpin`	Stable MAC addresses for Linux network adapters that randomize theirs every boot.	docs.rs
`ados-lora`	LoRa transmit governor with cited regional band plans, duty cycle, dwell time and airtime accounting.	docs.rs
`ados-crsf-codec`	no_std CRSF / ExpressLRS codec for RC channels, telemetry and parameter frames.	docs.rs
`ados-positioning`	Split mixed UBX, NMEA and RTCM3 GNSS streams, configure u-blox receivers and run an RTK base survey-in.	docs.rs
`ados-rtcm`	RTCM3 framing, CRC-24Q and MAVLink GPS_RTCM_DATA fragmentation for RTK corrections.	docs.rs
`ados-clock`	Map remote clocks onto the host clock: least-squares and envelope fits, TIMESYNC and a chrony sink.	docs.rs
`ados-swarm`	Swarm control laws: separation, flocking, formations, CBBA task allocation and a point-mass simulator.	docs.rs
`ados-mavlink-tunnel`	Send large messages over MAVLink TUNNEL frames with chunking and bounded reassembly.	docs.rs
`ados-display-driver`	Small-display output on Linux: SSD1306/SH1106 OLED over I2C, pixel packers and a framebuffer writer.	docs.rs
`ados-hmi`	Front-panel input: touchscreen calibration and gestures, button presses and rotary encoders.	docs.rs

§ADOS repositories

Repo	Runs on	What it does	Link
ADOS Mission Control	Browser, desktop (Electron)	Ground control station: FC setup, mission planning, flight, 3D simulation, fleet	ADOSMissionControl
ADOS Drone Agent	Companion computer on the drone, or a ground node	Onboard agent: MAVLink routing, HD video, long-range radio link, plugins, remote control	ADOSDroneAgent
ADOS Android GCS	Android phones and tablets	Native ground control app for agents on the LAN, direct flight controllers and the cloud	ADOSAndroidGCS
ADOS Extensions	Drone Agent and Mission Control	First-party signed plugins, each with an agent half and a GCS half	ADOSExtensions
ADOS MCP	Your machine	Model Context Protocol server that lets AI clients operate ADOS drones under scopes and a safety gate	ADOS-MCP
Documentation	docs.altnautica.com	Public docs for every ADOS product	Documentation

§License

Licensed under the MIT license. Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this crate by you shall be licensed as above, without any additional terms or conditions.

Re-exports§

pub use packet::*;

Modules§

cobs: Consistent Overhead Byte Stuffing (Cheshire & Baker), without the trailing 0x00 delimiter (the frame layer appends it).
crc: CRC-16/CCITT-FALSE: poly 0x1021, init 0xFFFF, no reflection, xorout 0.
packet: Packet payload structs, byte-exact per protocol v1. Every t_ns is hub time. Reserved fields are written as zero and ignored on receive.

Structs§

Deframer: Splits a byte stream into COBS blocks on 0x00. A block longer than N is discarded up to the next delimiter (resync).

Enums§

Error: Framing and parsing errors.
Push: Outcome of pushing one byte into a Deframer.

Constants§

MAX_FRAME: Largest wire frame including the 0x00 delimiter.
MAX_PAYLOAD: Largest payload (len) the protocol allows.
MAX_RAW: Largest raw (pre-COBS) frame.
RAW_OVERHEAD: Raw frame overhead: type (1) + len (2) + crc (2).

Functions§

decode_frame: Decode one COBS block (delimiter stripped) into buf and parse it.
decode_raw: Parse a raw frame (type, len, payload, crc).
encode_frame: Encode pkt as one wire frame (COBS + 0x00) into out, using scratch (≥ the raw length, MAX_RAW always suffices) for the raw frame. Returns the wire length including the delimiter.
encode_raw: Write the raw frame (type, len, payload, crc) of pkt into out; returns its length.