Overview
This document describes the Bluetooth Low Energy (BLE) protocol used to communicate between the Omi app and device. Use this reference when building custom apps or SDKs.BLE Discovery
The official app discovers the device by scanning for BLE devices with the nameOmi.
BLE Services
The Omi wearable implements three BLE services:Battery Service
Standard BLE battery level monitoring
Device Info Service
Device metadata and firmware version
Audio Service
Audio streaming and codec configuration
Battery Service
Battery notifications require firmware v1.5 or later. Earlier versions (1.0.x) do not support notifications.
This is the standard BLE Battery Service.
Device Information Service
Available since firmware version 1.0.3
This is the standard BLE Device Information Service.
Characteristics
Audio Streaming Service
This is the main service for streaming audio from the device to the app.Characteristics
Codec Types
The codec type characteristic determines how to decode the audio data:Starting with firmware v1.0.3, the default codec is Opus. Earlier versions used PCM 16-bit at 8 kHz.
Audio Data Format
Audio data is sent as BLE notifications on the Audio Data characteristic.Packet Structure
Header Format
Header Format
Each value update includes a 3-byte header:
Packet Fragmentation
Packet Fragmentation
Each audio packet contains 160 samples. If the packet exceeds
(negotiated BLE MTU - 3 bytes), it will be split across multiple value notifications.Example: PCM 16-bit at 16 kHz- 160 samples × 2 bytes = 320 bytes per packet
- On iOS devices, this typically results in:
- Notification 1: packet n, index 0, 251 bytes
- Notification 2: packet n+1, index 1, 75 bytes
Byte Order
Byte Order
All audio data is sent in little-endian format.
Implementation Example
Related
Python SDK
Python SDK with Opus decoding
Swift SDK
Native iOS SDK
React Native SDK
Cross-platform mobile SDK
Firmware
Compile custom firmware