[wedsa5]

Qardio shut down in 2025 and its app no longer works; the scales keep
working over BLE. The protocol comes from the last official Android app
(2.5.1) and was verified on a QardioBase 2 (B200).

Features:

• Weigh-ins over BLE: weight and impedance, plus the scale's own body
  fat, water, skeletal muscle and bone when it recognises the person.
  The weigh-in time is taken from the scale (Unix time in the result id).
• User management: each openScale user is stored as a profile on the
  scale (name, height, birthday, sex, weight unit), kept up to date and
  re-registered after a reset. Several phones can share one scale.
• Weigh-ins are saved to the active openScale user. Results the scale
  assigns to another profile are not saved (with a warning); guest
  weigh-ins follow the official app and are not saved unless "Save
  guest weigh-ins" is enabled. A guest result is held for 30 s so the
  user can pick their name on the scale.
• Device settings, in sections:
  • Scale (read-only, from the last connection): model, firmware and
    software revision, battery, whether a Wi-Fi network is stored, and
    the profiles on the scale (names for those registered from this
    phone; the scale's list carries ids only).
  • Scale settings: impedance and vibration switches, scale-wide,
    applied once on the next connection by rewriting the own profile
    slot (the flags travel with every profile write, as in the official
    app).
  • This phone: select my profile when connecting, save guest
    weigh-ins.
  • Maintenance: resend profiles; reset (the scale cannot delete a
    single user); experimental legacy reset of the official app for
    firmware before 1.8 (clear user and Wi-Fi config).

• Reset is a step of its own: it removes all users and the Wi-Fi network
  (verified on a B200) and restores the scale's defaults, then
  disconnects, so a reset scale can be given away. The next connection
  registers the profile again and restores the previous impedance and
  vibration settings.
• Status messages say whether a profile is added, updated, or only the
  scale settings change.
• Time sync and battery level.

Notes:

• Profile names must be lowercase letters/digits, max 6, as the
  official app enforced; the firmware never matches other names.
• Only values the scale reports are published; openScale derives BMI,
  BMR and lean body mass. The scale's "mt" (Qardio's muscle share) is
  documented and dropped; "sm" and "bmc" meanings are inferred and the
  evidence is written down in QardioBaseLib.
• QardioBaseLib has no Android dependencies (own small JSON reader and
  writer); both test classes run on the JVM. Library tests use captured
  B200 payloads.
• Only the QardioBase 2 (B200) was tested. The original QardioBase
  (B100) uses the same service in the official app but is untested.
• Photo of a QardioBase 2 added to the scale gallery
  (docs/scales/qardio_qardiobase2.jpg).
• QardioBase X is a different device (standard SIG profile) and is not
  covered.

Known limitations

Weigh-ins are saved only for the active openScale user. If the scale recognises another openScale user from the same phone, the result is not saved to that user. Use one phone per person, or switch the active user.
Driver settings are stored per handler class, not per scale. Two Qardio scales paired with one phone share the settings, including a pending reset.
Only the QardioBase 2 (B200) was tested on hardware. The original QardioBase (B100) is handled from the official app’s code; testing by a B100 owner is welcome.

[wedsa5]

Hello, requesting a review from @oliexdev or another maintainer

[oliexdev]

JSON. QardioBaseLib.Json re-implements a JSON reader/writer in ~150 lines. I'd prefer
org.json, which the app already uses: one less parser to maintain, and its error handling is
well tested. For the tests, @RunWith(RobolectricTestRunner::class) provides the real
implementation, as in the other tests here. Would you mind switching?

Wi-Fi read. The Wi-Fi config read returns SSID and passkey in clear text, only to show a
yes/no in the settings. GattScaleAdapter logs the first 24 bytes of every read, so the SSID ends
up in debug logs that users attach to issues. Does the scale report the Wi-Fi state anywhere else,
without the credentials? If not, please drop the read and the Wi-Fi entry in the settings — the
reset removes the network anyway.

Strings. 54 new strings is a lot for one driver, and each one goes to every translator on
Weblate. Please trim where it's easy:

• Merge the five profile/settings progress messages into "Updating the scale…" / "Scale updated."
• Reuse text_none and cap_battery.
• Drop the section descriptions; the headers are enough.
• Shorten the long texts to one or two sentences each, e.g. qardio_config_description,
  qardio_config_reset_desc, bt_warn_qardio_other_user, bt_warn_qardio_guest_not_saved.

[wedsa5]

@oliexdev

Thanks for the review! All three done:

• Switched to org.json; the lib tests now run under Robolectric.
• Dropped the Wi-Fi config read and the Wi-Fi row. There's a separate Wi-Fi state characteristic, but I couldn't verify it reports whether a network is stored, so I left it out. The reset still clears the network.
• Trimmed the strings: merged the progress messages, reused text_none and cap_battery, dropped the section descriptions, and shortened the long texts.

Also rebased onto master to fix the conflict in scale_catalog_remarks.txt.

[oliexdev]

Thanks for your PR 👍