# andTunes — device facts

Measured facts about the Rabbit R1 that the app is built around.
(Moved out of the old andtunes/TASKS.md board on 2026-09-24.)


- Panel **480 × 640 px**, physical density 320, **override density 160** — so
  the app sees a 480 × 640 **dp** canvas on a 2.88" screen (~278 real ppi).
- **One dp is about half its usual physical size here.** Double every stock
  value: body text 28–32 sp, list rows ≥ 88 dp, menu tiles ~213 dp. A 48 dp
  row would be 4.4 mm tall. Do not "fix" this by changing the device density —
  trav likes it where it is.
- Android 13 / API 33, `gsi_r1-userdebug`, arm64-v8a, 65 GB free.
- **The wheel can only ever give us detents.** `getevent -pl` (2026-09-14):
  `och1970_holl_key` advertises `KEY (0001): KEY_UP KEY_DOWN` and *nothing
  else* — no `EV_REL`/`REL_WHEEL`, no `EV_ABS`, no resolution. The `och1970`
  is a Hall latch, so the driver quantises the magnet into clicks and hands
  userspace one key press each. There is no sub-detent position to read
  without a kernel driver change, so every bit of nuance has to be derived
  from the *timing* between detents (see `WheelScroll`).
- Scroll wheel = input device `och1970_holl_key` → **KEY_UP / KEY_DOWN**,
  mapped by the stock `Generic.kl` (checked 2026-09-11 via `dumpsys input`)
  to **`KEYCODE_DPAD_UP` / `DPAD_DOWN`** — not volume. Side/PTT button sits
  on `mtk-kpd` with KEY_VOLUMEDOWN + KEY_POWER. Headset exposes
  KEY_PLAYPAUSE, so a MediaSession gets media keys for free.
- USB: set to come up as **`mtp,adb`** whenever the screen is unlocked
  (`adb shell svc usb setScreenUnlockedFunctions mtp`, 2026-09-11), so the
  gvfs mount sync uses and the adb install uses are both there at once.