bluetooth: normalize signal strength instead of raw rssi

Author: bbedward

src/bluetooth/device.cpp

@@ -1,4 +1,5 @@
 #include "device.hpp"
+#include <algorithm>
 
 #include <qcontainerfwd.h>
 #include <qdbusconnection.h>
@@ -46,12 +47,35 @@ BluetoothDevice::BluetoothDevice(const QString& path, QObject* parent): QObject(
 	}
 
 	this->properties.setInterface(this->mInterface);
+
+	this->bRssi.subscribe([this]() { emit this->signalStrengthChanged(); });
 }
 
 BluetoothAdapter* BluetoothDevice::adapter() const {
 	return Bluez::instance()->adapter(this->bAdapterPath.value().path());
 }
 
+qint32 BluetoothDevice::signalStrength() const {
+	// Convert RSSI (dBm) to a normalized 0-100 scale
+	// Based on practical Bluetooth RSSI ranges:
+	// -30 to -40 dBm = 85-100
+	// -40 to -55 dBm = 65-85
+	// -55 to -65 dBm = 45-65
+	// -65 to -75 dBm = 25-45
+	// -75 to -85 dBm = 10-25
+	// <= -85 dBm     = 0-10
+
+	auto rssiValue = this->bRssi.value();
+	if (rssiValue == 0) {
+		return 0;
+	}
+
+	auto rssi = std::max(static_cast<qint16>(-100), std::min(static_cast<qint16>(-30), rssiValue));
+	auto normalized = static_cast<qint32>(((rssi + 100) / 70.0) * 100.0);
+
+	return std::max(0, std::min(100, normalized));
+}
+
 void BluetoothDevice::setConnected(bool connected) {
 	if (connected == this->bConnected) return;
 

src/bluetooth/device.hpp

@@ -99,9 +99,8 @@ class BluetoothDevice: public QObject {
 	Q_PROPERTY(bool batteryAvailable READ batteryAvailable NOTIFY batteryAvailableChanged);
 	/// Battery level of the connected device, from `0.0` to `1.0`. Only valid if @@batteryAvailable is true.
 	Q_PROPERTY(qreal battery READ default NOTIFY batteryChanged BINDABLE bindableBattery);
-	/// Received Signal Strength Indicator in dBm. Only valid when device is discoverable/advertising.
-	/// Typical values range from -30 (very close) to -90 (far away). Values of 0 indicate no signal data.
-	Q_PROPERTY(qint16 rssi READ rssi NOTIFY rssiChanged BINDABLE bindableRssi);
+	/// Signal strength as a normalized score from 0 to 100, where higher is better (stronger signal).
+	Q_PROPERTY(qint32 signalStrength READ signalStrength NOTIFY signalStrengthChanged BINDABLE bindableSignalStrength);
 	/// The Bluetooth adapter this device belongs to.
 	Q_PROPERTY(BluetoothAdapter* adapter READ adapter NOTIFY adapterChanged);
 	/// DBus path of the device under the `org.bluez` system service.
@@ -148,7 +147,7 @@ class BluetoothDevice: public QObject {
 	[[nodiscard]] bool wakeAllowed() const { return this->bWakeAllowed; }
 	void setWakeAllowed(bool wakeAllowed);
 
-	[[nodiscard]] qint16 rssi() const { return this->bRssi; }
+	[[nodiscard]] qint32 signalStrength() const;
 
 	[[nodiscard]] bool pairing() const { return this->bPairing; }
 
@@ -164,7 +163,7 @@ class BluetoothDevice: public QObject {
 	[[nodiscard]] QBindable<QString> bindableIcon() { return &this->bIcon; }
 	[[nodiscard]] QBindable<qreal> bindableBattery() { return &this->bBattery; }
 	[[nodiscard]] QBindable<BluetoothDeviceState::Enum> bindableState() { return &this->bState; }
-	[[nodiscard]] QBindable<qint16> bindableRssi() { return &this->bRssi; }
+	[[nodiscard]] QBindable<qint32> bindableSignalStrength() { return &this->bSignalStrength; }
 
 	void addInterface(const QString& interface, const QVariantMap& properties);
 	void removeInterface(const QString& interface);
@@ -184,7 +183,7 @@ class BluetoothDevice: public QObject {
 	void iconChanged();
 	void batteryAvailableChanged();
 	void batteryChanged();
-	void rssiChanged();
+	void signalStrengthChanged();
 	void adapterChanged();
 
 private:
@@ -208,7 +207,8 @@ class BluetoothDevice: public QObject {
 	Q_OBJECT_BINDABLE_PROPERTY(BluetoothDevice, qreal, bBattery, &BluetoothDevice::batteryChanged);
 	Q_OBJECT_BINDABLE_PROPERTY(BluetoothDevice, BluetoothDeviceState::Enum, bState, &BluetoothDevice::stateChanged);
 	Q_OBJECT_BINDABLE_PROPERTY(BluetoothDevice, bool, bPairing, &BluetoothDevice::pairingChanged);
-	Q_OBJECT_BINDABLE_PROPERTY(BluetoothDevice, qint16, bRssi, &BluetoothDevice::rssiChanged);
+	Q_OBJECT_BINDABLE_PROPERTY(BluetoothDevice, qint32, bSignalStrength, &BluetoothDevice::signalStrengthChanged);
+	Q_OBJECT_BINDABLE_PROPERTY(BluetoothDevice, qint16, bRssi);
 
 	QS_DBUS_BINDABLE_PROPERTY_GROUP(BluetoothDevice, properties);
 	QS_DBUS_PROPERTY_BINDING(BluetoothDevice, pAddress, bAddress, properties, "Address");

src/dbus/properties.cpp

@@ -248,17 +248,8 @@ void DBusPropertyGroup::requestPropertyUpdate(DBusPropertyCore* property) {
 		const QDBusPendingReply<QDBusVariant> reply = *call;
 
 		if (reply.isError()) {
-			const auto& error = reply.error();
-			// For optional properties, suppress "No such property" errors specifically
-			if (!property->isRequired() && error.type() == QDBusError::InvalidArgs
-			    && error.message().contains("No such property"))
-			{
-				qCDebug(logDbusProperties).noquote() << "Error updating optional property" << propStr;
-				qCDebug(logDbusProperties) << error;
-			} else {
-				qCWarning(logDbusProperties).noquote() << "Error updating property" << propStr;
-				qCWarning(logDbusProperties) << error;
-			}
+			qCWarning(logDbusProperties).noquote() << "Error updating property" << propStr;
+			qCWarning(logDbusProperties) << reply.error();
 		} else {
 			this->tryUpdateProperty(property, reply.value().variant());
 		}