Bluetooth Classic Human Interface Device (HID) — input listener.

Use this for Bluetooth keyboards, mice, gamepads, finger PTTs, scanners, presenter remotes, and any device that emits HID input reports (button/key/axis events) over Bluetooth.

See Mob.Bt for pairing, discovery, and disconnect.

Scope

This module is read-only by design. HID hosts (phones) almost never send output reports to peripherals — that's a force-feedback / rumble-pack edge case. If your hardware genuinely needs output reports, open an issue.

Typical flow

# 1. Pair (Mob.Bt.pair/2)

# 2. Connect HID profile.
socket = Mob.Bt.Hid.connect(socket, device)
# {:bt, :hid_connected, session_id, device}

# 3. Input reports stream:
# {:bt, :hid_input, session_id,
#   %{usage_page: 0x07, usage: 0x29, value: 1}}
#   (HID Keyboard/Keypad, key 0x29 = Escape, pressed)

# 4. Disconnect (Mob.Bt.disconnect/2)

Input report shape

Reports are decoded by the Android HID stack into usage-page + usage + value triples per the HID Usage Tables spec. Common pages:

• 0x01 — Generic Desktop (mouse/joystick X/Y, wheel, etc.)
• 0x07 — Keyboard/Keypad
• 0x09 — Button (gamepad face buttons)
• 0x0C — Consumer (volume, play, mute, custom)
• 0xFF00–0xFFFF — Vendor-defined

Multi-axis events arrive as separate messages, one per axis. Synthesize combined input on the receive side if needed.

Receiving raw reports

If the device's HID descriptor is non-standard or the high-level :hid_input shape isn't sufficient, subscribe to raw reports with subscribe_raw/2 and parse the bytes yourself.

Stream: {:bt, :hid_raw_report, session_id, %{report_id: integer, bytes: binary}}.