Bluetooth Low Energy (BLE) - Apple Proximity Pairing Message

This document describes how the AirPods BLE "Proximity Pairing Message" is parsed and interpreted in the application. This message is broadcast by Apple devices (such as AirPods) and contains key information about the device's state, battery, and other properties.

Overview

When scanning for BLE devices, the application looks for manufacturer data with Apple's ID (0x004C). If the data starts with 0x07, it is identified as a Proximity Pairing Message. The message contains various fields, each representing a specific property of the AirPods.

Proximity Pairing Message Structure

Field Details

Device Model

Status Byte (Bitfield)

Ear Detection Logic

The in-ear detection uses XOR logic based on:

• Whether the right pod is primary (areValuesFlipped)
• Whether this pod is in the case (isThisPodInTheCase)

bool xorFactor = areValuesFlipped ^ deviceInfo.isThisPodInTheCase;
deviceInfo.isLeftPodInEar = xorFactor ? (status & 0x08) != 0 : (status & 0x02) != 0;  // Bit 3 or 1
deviceInfo.isRightPodInEar = xorFactor ? (status & 0x02) != 0 : (status & 0x08) != 0; // Bit 1 or 3

Primary Pod

Determined by bit 5 of the status byte:

• 1 = Left pod is primary
• 0 = Right pod is primary

This affects:

1. Battery level interpretation (which nibble corresponds to which pod)
2. Microphone assignment
3. Ear detection logic

Microphone Status

The active microphone is determined by:

deviceInfo.isLeftPodMicrophone = primaryLeft ^ deviceInfo.isThisPodInTheCase;
deviceInfo.isRightPodMicrophone = !primaryLeft ^ deviceInfo.isThisPodInTheCase;

Pods Battery Byte

• Upper nibble: one pod battery (depends on primary)
• Lower nibble: other pod battery

Flags & Case Battery Byte

• Upper nibble: case battery (same encoding as pods)
• Lower nibble: flags

Flags (Lower Nibble)

Lid Indicator

Device Color

Connection State

Example Message

For further details, see BleManager and BleScanner.