feat(bluetooth): add support for Healthkeep 280 smart scale

android_app/app/src/main/java/com/health/openscale/core/bluetooth/ScaleFactory.kt

@@ -19,6 +19,7 @@ package com.health.openscale.core.bluetooth
 
 import android.content.Context
 import androidx.annotation.VisibleForTesting
+import com.health.openscale.core.bluetooth.scales.HealthKeep280Handler
 import com.health.openscale.core.bluetooth.scales.BeurerBF450Handler
 import com.health.openscale.core.bluetooth.scales.ScaleDeviceHandler
 import com.health.openscale.core.bluetooth.scales.AAAxHandler
@@ -133,6 +134,7 @@ class ScaleFactory @Inject constructor(
         @VisibleForTesting
         internal fun createHandlers(): List<ScaleDeviceHandler> = listOf(
             // Exact-name match must precede generic LeFu/0xFFF0 handlers (first match wins).
+            HealthKeep280Handler(),
             PicoocHandler(),
             ActiveEraBF06Handler(),
             AfuB1Handler(),

android_app/app/src/main/java/com/health/openscale/core/bluetooth/scales/HealthKeep280Handler.kt

@@ -0,0 +1,143 @@
+/*
+ * openScale
+ * Copyright (C) 2026 openScale contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.health.openscale.core.bluetooth.scales
+
+import com.health.openscale.R
+import com.health.openscale.core.bluetooth.data.ScaleMeasurement
+import com.health.openscale.core.bluetooth.data.ScaleUser
+import com.health.openscale.core.bluetooth.libs.StandardImpedanceLib
+import com.health.openscale.core.service.ScannedDeviceInfo
+import java.util.Date
+import java.util.Locale
+import java.util.UUID
+
+class HealthKeep280Handler : ScaleDeviceHandler() {
+
+    private val SERVICE_UUID: UUID = uuid16(0xFFB0)
+    private val WRITE_CHAR: UUID = uuid16(0xFFB1)
+    private val NOTIFY_CHAR: UUID = uuid16(0xFFB2)
+    private val INDICATE_CHAR: UUID = uuid16(0xFFB3)
+
+    override fun supportFor(device: ScannedDeviceInfo): DeviceSupport? {
+        val name = device.name.trim().uppercase(Locale.US)
+
+        if (name.startsWith("HEALTHKEEP")) {
+            val caps = setOf(
+                DeviceCapability.LIVE_WEIGHT_STREAM,
+                DeviceCapability.BODY_COMPOSITION
+            )
+            return DeviceSupport(
+                displayName = "Healthkeep Smart Scale",
+                capabilities = caps,
+                implemented = caps,
+                linkMode = LinkMode.CONNECT_GATT
+            )
+        }
+
+        return null
+    }
+
+    override fun onConnected(user: ScaleUser) {
+        logI("Starting connection sequence for Healthkeep scale.")
+
+        setNotifyOn(SERVICE_UUID, NOTIFY_CHAR)
+        setNotifyOn(SERVICE_UUID, INDICATE_CHAR)
+
+        val sex = if (user.gender.isMale()) 0x01 else 0x02
+        val age = user.age
+        val height = user.bodyHeight.toInt()
+
+        val payload = byteArrayOf(
+            0xAC.toByte(), 0x02.toByte(), 0xFB.toByte(),
+            sex.toByte(), age.toByte(), height.toByte(),
+            0xCC.toByte(), 0x00.toByte()
+        )
+
+        var checksum = 0
+        for (i in 0..6) {
+            checksum += payload[i].toInt() and 0xFF
+        }
+        payload[7] = (checksum and 0xFF).toByte()
+
+        writeTo(SERVICE_UUID, WRITE_CHAR, payload, withResponse = true)
+        userInfo(R.string.bt_info_step_on_scale)
+    }
+
+    override fun onNotification(characteristic: UUID, data: ByteArray, user: ScaleUser) {
+        if (data.isEmpty()) return
+
+        // 1. Streaming peso live (Mostra a schermo il valore corrente senza salvare record multipli nel database)
+        if (characteristic == NOTIFY_CHAR && data.size >= 9) {
+            val status = data[4].toInt() and 0xFF
+            val weightRaw = ((data[6].toInt() and 0xFF) shl 16) or
+                            ((data[7].toInt() and 0xFF) shl 8) or
+                            (data[8].toInt() and 0xFF)
+            val weight = weightRaw / 1000.0f
+
+            if (status == 0x01 || status == 0x02) {
+                userInfo(R.string.bluetooth_scale_info_measuring_weight, weight)
+            }
+        }
+
+        // 2. Misura finale completa con BIA e Impedenza (Indicate su FFB3)
+        if (characteristic == INDICATE_CHAR && data.size >= 11) {
+            val cmd = data[3].toInt() and 0xFF
+            if (cmd == 0xA3) {
+                logD("Final measurement indication received: ${data.joinToString { "%02X".format(it) }}")
+
+                val weightRaw = ((data[5].toInt() and 0xFF) shl 16) or
+                                ((data[6].toInt() and 0xFF) shl 8) or
+                                (data[7].toInt() and 0xFF)
+                val weight = weightRaw / 1000.0f
+                val heartRate = data[8].toInt() and 0xFF
+                val impedance = ((data[9].toInt() and 0xFF) shl 8) or (data[10].toInt() and 0xFF)
+
+                val measurement = ScaleMeasurement().apply {
+                    this.userId = user.id
+                    this.weight = weight
+                    this.dateTime = Date()
+                    if (heartRate > 0) {
+                        this.heartRate = heartRate
+                    }
+                }
+
+                // Calcolo automatico di grasso, acqua, muscoli e ossa tramite la libreria BIA di openScale
+                if (impedance > 0 && user.bodyHeight > 0 && user.age > 0) {
+                    measurement.impedance = impedance.toDouble()
+
+                    val impedanceLib = StandardImpedanceLib(
+                        gender = user.gender,
+                        age = user.age,
+                        weightKg = weight.toDouble(),
+                        heightM = user.bodyHeight / 100.0,
+                        impedance = impedance.toDouble()
+                    )
+
+                    measurement.fat = impedanceLib.totalFatPercentage.toFloat().coerceIn(0f, 75f)
+                    measurement.water = impedanceLib.totalBodyWaterPercentage.toFloat().coerceIn(0f, 80f)
+                    measurement.muscle = impedanceLib.skeletalMusclePercentage.toFloat().coerceIn(0f, 99f)
+                    measurement.bone = impedanceLib.boneMassKg.toFloat().coerceIn(0f, 10f)
+                }
+
+                logI("Publishing final measurement: $weight kg, Impedance: $impedance Ohm, HR: $heartRate bpm")
+                publish(measurement)
+                requestDisconnect()
+            }
+        }
+    }
+}

android_app/app/src/test/java/com/health/openscale/core/bluetooth/ScaleCatalog.kt

@@ -19,6 +19,7 @@ package com.health.openscale.core.bluetooth
 
 import android.util.SparseArray
 import com.health.openscale.core.bluetooth.scales.AAAxHandler
+import com.health.openscale.core.bluetooth.scales.HealthKeep280Handler
 import com.health.openscale.core.bluetooth.scales.ActiveEraBF06Handler
 import com.health.openscale.core.bluetooth.scales.AfuB1Handler
 import com.health.openscale.core.bluetooth.scales.BeurerBF450Handler
@@ -160,6 +161,7 @@ object ScaleCatalog {
      */
     val fixtures: List<Fixture> = listOf(
         // --- Matched by advertised name ---
+        device("HEALTHKEEP 280") claimedBy HealthKeep280Handler::class.java,
         device("AE BS-06") claimedBy ActiveEraBF06Handler::class.java,
         device("AFU-BH-TZ-B1", uuid16(0xFC50)) claimedBy AfuB1Handler::class.java,
         device("Keep_S3") claimedBy KeepS3Handler::class.java,

android_app/app/src/test/java/com/health/openscale/core/bluetooth/scales/HealthKeep280HandlerTest.kt

@@ -0,0 +1,56 @@
+/*
+ * openScale
+ * Copyright (C) 2026 openScale contributors
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.health.openscale.core.bluetooth.scales
+
+import com.google.common.truth.Truth.assertThat
+import org.junit.Test
+
+class HealthKeep280HandlerTest {
+
+    @Test
+    fun testFinalMeasurementParsing() {
+        // Payload reale catturato da nRF Connect durante la pesata:
+        // Peso: 116.40 kg (0x01C6B0), Battito: 68 bpm (0x44), Impedenza: 357 Ohm (0x0165)
+        val data = byteArrayOf(
+            0xCF.toByte(), 0x08, 0x00, 0xA3.toByte(), 0x00,
+            0x01, 0xC6.toByte(), 0xB0.toByte(),
+            0x44,
+            0x01, 0x65,
+            0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x04
+        )
+
+        // Verifica comando BIA finale (0xA3)
+        val cmd = data[3].toInt() and 0xFF
+        assertThat(cmd).isEqualTo(0xA3)
+
+        // Estrazione e verifica peso (usando la sintassi corretta di Truth per i float)
+        val weightRaw = ((data[5].toInt() and 0xFF) shl 16) or
+                        ((data[6].toInt() and 0xFF) shl 8) or
+                        (data[7].toInt() and 0xFF)
+        val weight = weightRaw / 1000.0f
+        assertThat(weight).isWithin(0.01f).of(116.40f)
+
+        // Estrazione e verifica frequenza cardiaca (Heart Rate)
+        val heartRate = data[8].toInt() and 0xFF
+        assertThat(heartRate).isEqualTo(68)
+
+        // Estrazione e verifica impedenza corporea (BIA)
+        val impedance = ((data[9].toInt() and 0xFF) shl 8) or (data[10].toInt() and 0xFF)
+        assertThat(impedance).isEqualTo(357)
+    }
+}