diff --git a/services/sensorservice/Android.mk b/services/sensorservice/Android.mk
index 75f690f..7e17fdd 100644
--- a/services/sensorservice/Android.mk
+++ b/services/sensorservice/Android.mk
@@ -2,7 +2,13 @@
 include $(CLEAR_VARS)
 
 LOCAL_SRC_FILES:= \
-    SensorService.cpp
+	GravitySensor.cpp \
+	LinearAccelerationSensor.cpp \
+	RotationVectorSensor.cpp \
+    SensorService.cpp \
+    SensorInterface.cpp \
+    SensorDevice.cpp \
+    SecondOrderLowPassFilter.cpp
 
 LOCAL_CFLAGS:= -DLOG_TAG=\"SensorService\"
 
diff --git a/services/sensorservice/GravitySensor.cpp b/services/sensorservice/GravitySensor.cpp
new file mode 100644
index 0000000..18bd359
--- /dev/null
+++ b/services/sensorservice/GravitySensor.cpp
@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <math.h>
+#include <sys/types.h>
+
+#include <utils/Errors.h>
+
+#include <hardware/sensors.h>
+
+#include "GravitySensor.h"
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+GravitySensor::GravitySensor(sensor_t const* list, size_t count)
+    : mSensorDevice(SensorDevice::getInstance()),
+      mEnabled(false), mAccTime(0),
+      mLowPass(M_SQRT1_2, 1),
+      mX(mLowPass), mY(mLowPass), mZ(mLowPass)
+
+{
+    for (size_t i=0 ; i<count ; i++) {
+        if (list[i].type == SENSOR_TYPE_ACCELEROMETER) {
+            mAccelerometer = Sensor(list + i);
+            break;
+        }
+    }
+}
+
+bool GravitySensor::process(sensors_event_t* outEvent,
+        const sensors_event_t& event)
+{
+    const static double NS2S = 1.0 / 1000000000.0;
+    if (event.type == SENSOR_TYPE_ACCELEROMETER) {
+        float x, y, z;
+        const double now = event.timestamp * NS2S;
+        if (mAccTime == 0) {
+            x = mX.init(event.acceleration.x);
+            y = mY.init(event.acceleration.y);
+            z = mZ.init(event.acceleration.z);
+        } else {
+            double dT = now - mAccTime;
+            mLowPass.setSamplingPeriod(dT);
+            x = mX(event.acceleration.x);
+            y = mY(event.acceleration.y);
+            z = mZ(event.acceleration.z);
+        }
+        mAccTime = now;
+        *outEvent = event;
+        outEvent->data[0] = x;
+        outEvent->data[1] = y;
+        outEvent->data[2] = z;
+        outEvent->sensor = '_grv';
+        outEvent->type = SENSOR_TYPE_GRAVITY;
+        return true;
+    }
+    return false;
+}
+
+bool GravitySensor::isEnabled() const {
+    return mEnabled;
+}
+
+status_t GravitySensor::activate(void* ident, bool enabled) {
+    status_t err = mSensorDevice.activate(this, mAccelerometer.getHandle(), enabled);
+    if (err == NO_ERROR) {
+        mEnabled = enabled;
+        if (enabled) {
+            mAccTime = 0;
+        }
+    }
+    return err;
+}
+
+status_t GravitySensor::setDelay(void* ident, int handle, int64_t ns)
+{
+    return mSensorDevice.setDelay(this, mAccelerometer.getHandle(), ns);
+}
+
+Sensor GravitySensor::getSensor() const {
+    sensor_t hwSensor;
+    hwSensor.name       = "Gravity Sensor";
+    hwSensor.vendor     = "Google Inc.";
+    hwSensor.version    = 1;
+    hwSensor.handle     = '_grv';
+    hwSensor.type       = SENSOR_TYPE_GRAVITY;
+    hwSensor.maxRange   = mAccelerometer.getMaxValue();
+    hwSensor.resolution = mAccelerometer.getResolution();
+    hwSensor.power      = mAccelerometer.getPowerUsage();
+    hwSensor.minDelay   = mAccelerometer.getMinDelay();
+    Sensor sensor(&hwSensor);
+    return sensor;
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
diff --git a/services/sensorservice/GravitySensor.h b/services/sensorservice/GravitySensor.h
new file mode 100644
index 0000000..f9850b7
--- /dev/null
+++ b/services/sensorservice/GravitySensor.h
@@ -0,0 +1,56 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_GRAVITY_SENSOR_H
+#define ANDROID_GRAVITY_SENSOR_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <gui/Sensor.h>
+
+#include "SensorDevice.h"
+#include "SensorInterface.h"
+#include "SecondOrderLowPassFilter.h"
+
+// ---------------------------------------------------------------------------
+namespace android {
+// ---------------------------------------------------------------------------
+
+class GravitySensor : public SensorInterface {
+    SensorDevice& mSensorDevice;
+    Sensor mAccelerometer;
+    bool mEnabled;
+    double mAccTime;
+
+    SecondOrderLowPassFilter mLowPass;
+    BiquadFilter mX, mY, mZ;
+
+public:
+    GravitySensor(sensor_t const* list, size_t count);
+    virtual bool process(sensors_event_t* outEvent,
+            const sensors_event_t& event);
+    virtual bool isEnabled() const;
+    virtual status_t activate(void* ident, bool enabled);
+    virtual status_t setDelay(void* ident, int handle, int64_t ns);
+    virtual Sensor getSensor() const;
+    virtual bool isVirtual() const { return true; }
+};
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_GRAVITY_SENSOR_H
diff --git a/services/sensorservice/LinearAccelerationSensor.cpp b/services/sensorservice/LinearAccelerationSensor.cpp
new file mode 100644
index 0000000..2dc12dc
--- /dev/null
+++ b/services/sensorservice/LinearAccelerationSensor.cpp
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <math.h>
+#include <sys/types.h>
+
+#include <utils/Errors.h>
+
+#include <hardware/sensors.h>
+
+#include "LinearAccelerationSensor.h"
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+LinearAccelerationSensor::LinearAccelerationSensor(sensor_t const* list, size_t count)
+    : mSensorDevice(SensorDevice::getInstance()),
+      mGravitySensor(list, count)
+{
+    mData[0] = mData[1] = mData[2] = 0;
+}
+
+bool LinearAccelerationSensor::process(sensors_event_t* outEvent,
+        const sensors_event_t& event)
+{
+    bool result = mGravitySensor.process(outEvent, event);
+    if (result) {
+        if (event.type == SENSOR_TYPE_ACCELEROMETER) {
+            mData[0] = event.acceleration.x;
+            mData[1] = event.acceleration.y;
+            mData[2] = event.acceleration.z;
+        }
+        outEvent->data[0] = mData[0] - outEvent->data[0];
+        outEvent->data[1] = mData[1] - outEvent->data[1];
+        outEvent->data[2] = mData[2] - outEvent->data[2];
+        outEvent->sensor = '_lin';
+        outEvent->type = SENSOR_TYPE_LINEAR_ACCELERATION;
+    }
+    return result;
+}
+
+bool LinearAccelerationSensor::isEnabled() const {
+    return mGravitySensor.isEnabled();
+}
+
+status_t LinearAccelerationSensor::activate(void* ident, bool enabled) {
+    return mGravitySensor.activate(ident, enabled);
+}
+
+status_t LinearAccelerationSensor::setDelay(void* ident, int handle, int64_t ns) {
+    return mGravitySensor.setDelay(ident, handle, ns);
+}
+
+Sensor LinearAccelerationSensor::getSensor() const {
+    Sensor gsensor(mGravitySensor.getSensor());
+    sensor_t hwSensor;
+    hwSensor.name       = "Linear Acceleration Sensor";
+    hwSensor.vendor     = "Google Inc.";
+    hwSensor.version    = 1;
+    hwSensor.handle     = '_lin';
+    hwSensor.type       = SENSOR_TYPE_LINEAR_ACCELERATION;
+    hwSensor.maxRange   = gsensor.getMaxValue();
+    hwSensor.resolution = gsensor.getResolution();
+    hwSensor.power      = gsensor.getPowerUsage();
+    hwSensor.minDelay   = gsensor.getMinDelay();
+    Sensor sensor(&hwSensor);
+    return sensor;
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
diff --git a/services/sensorservice/LinearAccelerationSensor.h b/services/sensorservice/LinearAccelerationSensor.h
new file mode 100644
index 0000000..ee918ce
--- /dev/null
+++ b/services/sensorservice/LinearAccelerationSensor.h
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_LINEAR_ACCELERATION_SENSOR_H
+#define ANDROID_LINEAR_ACCELERATION_SENSOR_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <gui/Sensor.h>
+
+#include "SensorDevice.h"
+#include "SensorInterface.h"
+#include "GravitySensor.h"
+
+// ---------------------------------------------------------------------------
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+class LinearAccelerationSensor : public SensorInterface {
+    SensorDevice& mSensorDevice;
+    GravitySensor mGravitySensor;
+    float mData[3];
+
+    virtual bool process(sensors_event_t* outEvent,
+            const sensors_event_t& event);
+public:
+    LinearAccelerationSensor(sensor_t const* list, size_t count);
+    virtual bool isEnabled() const;
+    virtual status_t activate(void* ident, bool enabled);
+    virtual status_t setDelay(void* ident, int handle, int64_t ns);
+    virtual Sensor getSensor() const;
+    virtual bool isVirtual() const { return true; }
+};
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_LINEAR_ACCELERATION_SENSOR_H
diff --git a/services/sensorservice/RotationVectorSensor.cpp b/services/sensorservice/RotationVectorSensor.cpp
new file mode 100644
index 0000000..6f4b8be
--- /dev/null
+++ b/services/sensorservice/RotationVectorSensor.cpp
@@ -0,0 +1,174 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <math.h>
+#include <sys/types.h>
+
+#include <utils/Errors.h>
+
+#include <hardware/sensors.h>
+
+#include "RotationVectorSensor.h"
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+template <typename T>
+static inline T clamp(T v) {
+    return v < 0 ? 0 : v;
+}
+
+RotationVectorSensor::RotationVectorSensor(sensor_t const* list, size_t count)
+    : mSensorDevice(SensorDevice::getInstance()),
+      mEnabled(false),
+      mALowPass(M_SQRT1_2, 5.0f),
+      mAX(mALowPass), mAY(mALowPass), mAZ(mALowPass),
+      mMLowPass(M_SQRT1_2, 2.5f),
+      mMX(mMLowPass), mMY(mMLowPass), mMZ(mMLowPass)
+{
+    for (size_t i=0 ; i<count ; i++) {
+        if (list[i].type == SENSOR_TYPE_ACCELEROMETER) {
+            mAcc = Sensor(list + i);
+        }
+        if (list[i].type == SENSOR_TYPE_MAGNETIC_FIELD) {
+            mMag = Sensor(list + i);
+        }
+    }
+    memset(mMagData, 0, sizeof(mMagData));
+}
+
+bool RotationVectorSensor::process(sensors_event_t* outEvent,
+        const sensors_event_t& event)
+{
+    const static double NS2S = 1.0 / 1000000000.0;
+    if (event.type == SENSOR_TYPE_MAGNETIC_FIELD) {
+        const double now = event.timestamp * NS2S;
+        if (mMagTime == 0) {
+            mMagData[0] = mMX.init(event.magnetic.x);
+            mMagData[1] = mMY.init(event.magnetic.y);
+            mMagData[2] = mMZ.init(event.magnetic.z);
+        } else {
+            double dT = now - mMagTime;
+            mMLowPass.setSamplingPeriod(dT);
+            mMagData[0] = mMX(event.magnetic.x);
+            mMagData[1] = mMY(event.magnetic.y);
+            mMagData[2] = mMZ(event.magnetic.z);
+        }
+        mMagTime = now;
+    }
+    if (event.type == SENSOR_TYPE_ACCELEROMETER) {
+        const double now = event.timestamp * NS2S;
+        float Ax, Ay, Az;
+        if (mAccTime == 0) {
+            Ax = mAX.init(event.acceleration.x);
+            Ay = mAY.init(event.acceleration.y);
+            Az = mAZ.init(event.acceleration.z);
+        } else {
+            double dT = now - mAccTime;
+            mALowPass.setSamplingPeriod(dT);
+            Ax = mAX(event.acceleration.x);
+            Ay = mAY(event.acceleration.y);
+            Az = mAZ(event.acceleration.z);
+        }
+        mAccTime = now;
+        const float Ex = mMagData[0];
+        const float Ey = mMagData[1];
+        const float Ez = mMagData[2];
+        float Hx = Ey*Az - Ez*Ay;
+        float Hy = Ez*Ax - Ex*Az;
+        float Hz = Ex*Ay - Ey*Ax;
+        const float normH = sqrtf(Hx*Hx + Hy*Hy + Hz*Hz);
+        if (normH < 0.1f) {
+            // device is close to free fall (or in space?), or close to
+            // magnetic north pole. Typical values are  > 100.
+            return false;
+        }
+        const float invH = 1.0f / normH;
+        const float invA = 1.0f / sqrtf(Ax*Ax + Ay*Ay + Az*Az);
+        Hx *= invH;
+        Hy *= invH;
+        Hz *= invH;
+        Ax *= invA;
+        Ay *= invA;
+        Az *= invA;
+        const float Mx = Ay*Hz - Az*Hy;
+        const float My = Az*Hx - Ax*Hz;
+        const float Mz = Ax*Hy - Ay*Hx;
+
+        // matrix to rotation vector (normalized quaternion)
+        float qw = sqrtf( clamp( Hx + My + Az + 1) * 0.25f );
+        float qx = sqrtf( clamp( Hx - My - Az + 1) * 0.25f );
+        float qy = sqrtf( clamp(-Hx + My - Az + 1) * 0.25f );
+        float qz = sqrtf( clamp(-Hx - My + Az + 1) * 0.25f );
+        const float n = 1.0f / (qw*qw + qx*qx + qy*qy + qz*qz);
+        qx = copysignf(qx, Ay - Mz) * n;
+        qy = copysignf(qy, Hz - Ax) * n;
+        qz = copysignf(qz, Mx - Hy) * n;
+
+        *outEvent = event;
+        outEvent->data[0] = qx;
+        outEvent->data[1] = qy;
+        outEvent->data[2] = qz;
+        outEvent->sensor = '_rov';
+        outEvent->type = SENSOR_TYPE_ROTATION_VECTOR;
+        return true;
+    }
+    return false;
+}
+
+bool RotationVectorSensor::isEnabled() const {
+    return mEnabled;
+}
+
+status_t RotationVectorSensor::activate(void* ident, bool enabled) {
+    if (mEnabled != enabled) {
+        mSensorDevice.activate(this, mAcc.getHandle(), enabled);
+        mSensorDevice.activate(this, mMag.getHandle(), enabled);
+        mEnabled = enabled;
+        if (enabled) {
+            mMagTime = 0;
+            mAccTime = 0;
+        }
+    }
+    return NO_ERROR;
+}
+
+status_t RotationVectorSensor::setDelay(void* ident, int handle, int64_t ns)
+{
+    mSensorDevice.setDelay(this, mAcc.getHandle(), ns);
+    mSensorDevice.setDelay(this, mMag.getHandle(), ns);
+    return NO_ERROR;
+}
+
+Sensor RotationVectorSensor::getSensor() const {
+    sensor_t hwSensor;
+    hwSensor.name       = "Rotation Vector Sensor";
+    hwSensor.vendor     = "Google Inc.";
+    hwSensor.version    = 1;
+    hwSensor.handle     = '_rov';
+    hwSensor.type       = SENSOR_TYPE_ROTATION_VECTOR;
+    hwSensor.maxRange   = 1;
+    hwSensor.resolution = 1.0f / (1<<24);
+    hwSensor.power      = mAcc.getPowerUsage() + mMag.getPowerUsage();
+    hwSensor.minDelay   = mAcc.getMinDelay();
+    Sensor sensor(&hwSensor);
+    return sensor;
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
diff --git a/services/sensorservice/RotationVectorSensor.h b/services/sensorservice/RotationVectorSensor.h
new file mode 100644
index 0000000..e7f28c9
--- /dev/null
+++ b/services/sensorservice/RotationVectorSensor.h
@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_ROTATION_VECTOR_SENSOR_H
+#define ANDROID_ROTATION_VECTOR_SENSOR_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <gui/Sensor.h>
+
+#include "SensorDevice.h"
+#include "SensorInterface.h"
+#include "SecondOrderLowPassFilter.h"
+
+// ---------------------------------------------------------------------------
+namespace android {
+// ---------------------------------------------------------------------------
+
+class RotationVectorSensor : public SensorInterface {
+    SensorDevice& mSensorDevice;
+    Sensor mAcc;
+    Sensor mMag;
+    bool mEnabled;
+    float mMagData[3];
+    double mAccTime;
+    double mMagTime;
+    SecondOrderLowPassFilter mALowPass;
+    BiquadFilter mAX, mAY, mAZ;
+    SecondOrderLowPassFilter mMLowPass;
+    BiquadFilter mMX, mMY, mMZ;
+
+public:
+    RotationVectorSensor(sensor_t const* list, size_t count);
+    virtual bool process(sensors_event_t* outEvent,
+            const sensors_event_t& event);
+    virtual bool isEnabled() const;
+    virtual status_t activate(void* ident, bool enabled);
+    virtual status_t setDelay(void* ident, int handle, int64_t ns);
+    virtual Sensor getSensor() const;
+    virtual bool isVirtual() const { return true; }
+};
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_ROTATION_VECTOR_SENSOR_H
diff --git a/services/sensorservice/SecondOrderLowPassFilter.cpp b/services/sensorservice/SecondOrderLowPassFilter.cpp
new file mode 100644
index 0000000..e13e136
--- /dev/null
+++ b/services/sensorservice/SecondOrderLowPassFilter.cpp
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <sys/types.h>
+#include <math.h>
+
+#include <cutils/log.h>
+
+#include "SecondOrderLowPassFilter.h"
+
+// ---------------------------------------------------------------------------
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+SecondOrderLowPassFilter::SecondOrderLowPassFilter(float Q, float fc)
+    : iQ(1.0f / Q), fc(fc)
+{
+}
+
+void SecondOrderLowPassFilter::setSamplingPeriod(float dT)
+{
+    K = tanf(float(M_PI) * fc * dT);
+    iD = 1.0f / (K*K + K*iQ + 1);
+    a0 = K*K*iD;
+    a1 = 2.0f * a0;
+    b1 = 2.0f*(K*K - 1)*iD;
+    b2 = (K*K - K*iQ + 1)*iD;
+}
+
+// ---------------------------------------------------------------------------
+
+BiquadFilter::BiquadFilter(const SecondOrderLowPassFilter& s)
+    : s(s)
+{
+}
+
+float BiquadFilter::init(float x)
+{
+    x1 = x2 = x;
+    y1 = y2 = x;
+    return x;
+}
+
+float BiquadFilter::operator()(float x)
+{
+    float y = (x + x2)*s.a0 + x1*s.a1 - y1*s.b1 - y2*s.b2;
+    x2 = x1;
+    y2 = y1;
+    x1 = x;
+    y1 = y;
+    return y;
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android
diff --git a/services/sensorservice/SecondOrderLowPassFilter.h b/services/sensorservice/SecondOrderLowPassFilter.h
new file mode 100644
index 0000000..998ca35
--- /dev/null
+++ b/services/sensorservice/SecondOrderLowPassFilter.h
@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_SECOND_ORDER_LOW_PASS_FILTER_H
+#define ANDROID_SECOND_ORDER_LOW_PASS_FILTER_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+// ---------------------------------------------------------------------------
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+class BiquadFilter;
+
+/*
+ * State of a 2nd order low-pass IIR filter
+ */
+class SecondOrderLowPassFilter {
+    friend class BiquadFilter;
+    float iQ, fc;
+    float K, iD;
+    float a0, a1;
+    float b1, b2;
+public:
+    SecondOrderLowPassFilter(float Q, float fc);
+    void setSamplingPeriod(float dT);
+};
+
+/*
+ * Implements a Biquad IIR filter
+ */
+class BiquadFilter {
+    float x1, x2;
+    float y1, y2;
+    const SecondOrderLowPassFilter& s;
+public:
+    BiquadFilter(const SecondOrderLowPassFilter& s);
+    float init(float in);
+    float operator()(float in);
+};
+
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_SECOND_ORDER_LOW_PASS_FILTER_H
diff --git a/services/sensorservice/SensorDevice.cpp b/services/sensorservice/SensorDevice.cpp
new file mode 100644
index 0000000..73f85ba
--- /dev/null
+++ b/services/sensorservice/SensorDevice.cpp
@@ -0,0 +1,239 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <math.h>
+#include <sys/types.h>
+
+#include <utils/Atomic.h>
+#include <utils/Errors.h>
+#include <utils/Singleton.h>
+
+#include <binder/BinderService.h>
+#include <binder/Parcel.h>
+#include <binder/IServiceManager.h>
+
+#include <hardware/sensors.h>
+
+#include "SensorDevice.h"
+
+namespace android {
+// ---------------------------------------------------------------------------
+class BatteryService : public Singleton<BatteryService> {
+    static const int TRANSACTION_noteStartSensor = IBinder::FIRST_CALL_TRANSACTION + 3;
+    static const int TRANSACTION_noteStopSensor = IBinder::FIRST_CALL_TRANSACTION + 4;
+    static const String16 DESCRIPTOR;
+
+    friend class Singleton<BatteryService>;
+    sp<IBinder> mBatteryStatService;
+
+    BatteryService() {
+        const sp<IServiceManager> sm(defaultServiceManager());
+        if (sm != NULL) {
+            const String16 name("batteryinfo");
+            mBatteryStatService = sm->getService(name);
+        }
+    }
+
+    status_t noteStartSensor(int uid, int handle) {
+        Parcel data, reply;
+        data.writeInterfaceToken(DESCRIPTOR);
+        data.writeInt32(uid);
+        data.writeInt32(handle);
+        status_t err = mBatteryStatService->transact(
+                TRANSACTION_noteStartSensor, data, &reply, 0);
+        err = reply.readExceptionCode();
+        return err;
+    }
+
+    status_t noteStopSensor(int uid, int handle) {
+        Parcel data, reply;
+        data.writeInterfaceToken(DESCRIPTOR);
+        data.writeInt32(uid);
+        data.writeInt32(handle);
+        status_t err = mBatteryStatService->transact(
+                TRANSACTION_noteStopSensor, data, &reply, 0);
+        err = reply.readExceptionCode();
+        return err;
+    }
+
+public:
+    void enableSensor(int handle) {
+        if (mBatteryStatService != 0) {
+            int uid = IPCThreadState::self()->getCallingUid();
+            int64_t identity = IPCThreadState::self()->clearCallingIdentity();
+            noteStartSensor(uid, handle);
+            IPCThreadState::self()->restoreCallingIdentity(identity);
+        }
+    }
+    void disableSensor(int handle) {
+        if (mBatteryStatService != 0) {
+            int uid = IPCThreadState::self()->getCallingUid();
+            int64_t identity = IPCThreadState::self()->clearCallingIdentity();
+            noteStopSensor(uid, handle);
+            IPCThreadState::self()->restoreCallingIdentity(identity);
+        }
+    }
+};
+
+const String16 BatteryService::DESCRIPTOR("com.android.internal.app.IBatteryStats");
+
+ANDROID_SINGLETON_STATIC_INSTANCE(BatteryService)
+
+// ---------------------------------------------------------------------------
+
+ANDROID_SINGLETON_STATIC_INSTANCE(SensorDevice)
+
+SensorDevice::SensorDevice()
+    :  mSensorDevice(0),
+       mSensorModule(0)
+{
+    status_t err = hw_get_module(SENSORS_HARDWARE_MODULE_ID,
+            (hw_module_t const**)&mSensorModule);
+
+    LOGE_IF(err, "couldn't load %s module (%s)",
+            SENSORS_HARDWARE_MODULE_ID, strerror(-err));
+
+    if (mSensorModule) {
+        err = sensors_open(&mSensorModule->common, &mSensorDevice);
+
+        LOGE_IF(err, "couldn't open device for module %s (%s)",
+                SENSORS_HARDWARE_MODULE_ID, strerror(-err));
+
+        if (mSensorDevice) {
+            sensor_t const* list;
+            ssize_t count = mSensorModule->get_sensors_list(mSensorModule, &list);
+            mActivationCount.setCapacity(count);
+            Info model;
+            for (size_t i=0 ; i<size_t(count) ; i++) {
+                mActivationCount.add(list[i].handle, model);
+                mSensorDevice->activate(mSensorDevice, list[i].handle, 0);
+            }
+        }
+    }
+}
+
+void SensorDevice::dump(String8& result, char* buffer, size_t SIZE)
+{
+    if (!mSensorModule) return;
+    sensor_t const* list;
+    ssize_t count = mSensorModule->get_sensors_list(mSensorModule, &list);
+
+    snprintf(buffer, SIZE, "%d h/w sensors:\n", int(count));
+    result.append(buffer);
+
+    Mutex::Autolock _l(mLock);
+    for (size_t i=0 ; i<size_t(count) ; i++) {
+        snprintf(buffer, SIZE, "handle=0x%08x, active-count=%d / %d\n",
+                list[i].handle,
+                mActivationCount.valueFor(list[i].handle).count,
+                mActivationCount.valueFor(list[i].handle).rates.size());
+        result.append(buffer);
+    }
+}
+
+ssize_t SensorDevice::getSensorList(sensor_t const** list) {
+    if (!mSensorModule) return NO_INIT;
+    ssize_t count = mSensorModule->get_sensors_list(mSensorModule, list);
+    return count;
+}
+
+status_t SensorDevice::initCheck() const {
+    return mSensorDevice && mSensorModule ? NO_ERROR : NO_INIT;
+}
+
+ssize_t SensorDevice::poll(sensors_event_t* buffer, size_t count) {
+    if (!mSensorDevice) return NO_INIT;
+    return mSensorDevice->poll(mSensorDevice, buffer, count);
+}
+
+status_t SensorDevice::activate(void* ident, int handle, int enabled)
+{
+    if (!mSensorDevice) return NO_INIT;
+    status_t err(NO_ERROR);
+    bool actuateHardware = false;
+
+    Info& info( mActivationCount.editValueFor(handle) );
+    int32_t& count(info.count);
+    if (enabled) {
+        if (android_atomic_inc(&count) == 0) {
+            actuateHardware = true;
+        }
+        Mutex::Autolock _l(mLock);
+        if (info.rates.indexOfKey(ident) < 0) {
+            info.rates.add(ident, DEFAULT_EVENTS_PERIOD);
+        }
+    } else {
+        if (android_atomic_dec(&count) == 1) {
+            actuateHardware = true;
+        }
+        Mutex::Autolock _l(mLock);
+        info.rates.removeItem(ident);
+    }
+    if (actuateHardware) {
+        err = mSensorDevice->activate(mSensorDevice, handle, enabled);
+        if (enabled) {
+            LOGE_IF(err, "Error activating sensor %d (%s)", handle, strerror(-err));
+            if (err == 0) {
+                BatteryService::getInstance().enableSensor(handle);
+            }
+        } else {
+            if (err == 0) {
+                BatteryService::getInstance().disableSensor(handle);
+            }
+        }
+    }
+
+    if (!actuateHardware || enabled) {
+        Mutex::Autolock _l(mLock);
+        nsecs_t ns = info.rates.valueAt(0);
+        for (size_t i=1 ; i<info.rates.size() ; i++) {
+            if (info.rates.valueAt(i) < ns) {
+                nsecs_t cur = info.rates.valueAt(i);
+                if (cur < ns) {
+                    ns = cur;
+                }
+            }
+        }
+        mSensorDevice->setDelay(mSensorDevice, handle, ns);
+    }
+
+    return err;
+}
+
+status_t SensorDevice::setDelay(void* ident, int handle, int64_t ns)
+{
+    if (!mSensorDevice) return NO_INIT;
+    Info& info( mActivationCount.editValueFor(handle) );
+    { // scope for lock
+        Mutex::Autolock _l(mLock);
+        ssize_t index = info.rates.indexOfKey(ident);
+        if (index < 0) return BAD_INDEX;
+        info.rates.editValueAt(index) = ns;
+        ns = info.rates.valueAt(0);
+        for (size_t i=1 ; i<info.rates.size() ; i++) {
+            nsecs_t cur = info.rates.valueAt(i);
+            if (cur < ns) {
+                ns = cur;
+            }
+        }
+    }
+    return mSensorDevice->setDelay(mSensorDevice, handle, ns);
+}
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
diff --git a/services/sensorservice/SensorDevice.h b/services/sensorservice/SensorDevice.h
new file mode 100644
index 0000000..63ecbcd
--- /dev/null
+++ b/services/sensorservice/SensorDevice.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_SENSOR_DEVICE_H
+#define ANDROID_SENSOR_DEVICE_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <utils/KeyedVector.h>
+#include <utils/Singleton.h>
+#include <utils/String8.h>
+
+#include <gui/Sensor.h>
+
+// ---------------------------------------------------------------------------
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+static const nsecs_t DEFAULT_EVENTS_PERIOD = 200000000; //    5 Hz
+
+class SensorDevice : public Singleton<SensorDevice> {
+    friend class Singleton<SensorDevice>;
+    struct sensors_poll_device_t* mSensorDevice;
+    struct sensors_module_t* mSensorModule;
+    Mutex mLock; // protect mActivationCount[].rates
+    // fixed-size array after construction
+    struct Info {
+        Info() : count(0) { }
+        int32_t count;
+        KeyedVector<void*, nsecs_t> rates;
+    };
+    DefaultKeyedVector<int, Info> mActivationCount;
+
+    SensorDevice();
+public:
+    ssize_t getSensorList(sensor_t const** list);
+    status_t initCheck() const;
+    ssize_t poll(sensors_event_t* buffer, size_t count);
+    status_t activate(void* ident, int handle, int enabled);
+    status_t setDelay(void* ident, int handle, int64_t ns);
+    void dump(String8& result, char* buffer, size_t SIZE);
+};
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_SENSOR_DEVICE_H
diff --git a/services/sensorservice/SensorInterface.cpp b/services/sensorservice/SensorInterface.cpp
new file mode 100644
index 0000000..93d23d9
--- /dev/null
+++ b/services/sensorservice/SensorInterface.cpp
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <cutils/log.h>
+
+#include "SensorInterface.h"
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+SensorInterface::~SensorInterface()
+{
+}
+
+// ---------------------------------------------------------------------------
+
+HardwareSensor::HardwareSensor(const sensor_t& sensor)
+    : mSensorDevice(SensorDevice::getInstance()),
+      mSensor(&sensor), mEnabled(false)
+{
+    LOGI("%s", sensor.name);
+}
+
+HardwareSensor::~HardwareSensor() {
+}
+
+bool HardwareSensor::process(sensors_event_t* outEvent,
+        const sensors_event_t& event) {
+    *outEvent = event;
+    return true;
+}
+
+bool HardwareSensor::isEnabled() const {
+    return mEnabled;
+}
+
+status_t HardwareSensor::activate(void* ident,bool enabled) {
+    status_t err = mSensorDevice.activate(ident, mSensor.getHandle(), enabled);
+    if (err == NO_ERROR)
+        mEnabled = enabled;
+    return err;
+}
+
+status_t HardwareSensor::setDelay(void* ident, int handle, int64_t ns) {
+    return mSensorDevice.setDelay(ident, handle, ns);
+}
+
+Sensor HardwareSensor::getSensor() const {
+    return mSensor;
+}
+
+
+// ---------------------------------------------------------------------------
+}; // namespace android
diff --git a/services/sensorservice/SensorInterface.h b/services/sensorservice/SensorInterface.h
new file mode 100644
index 0000000..eebd563
--- /dev/null
+++ b/services/sensorservice/SensorInterface.h
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef ANDROID_SENSOR_INTERFACE_H
+#define ANDROID_SENSOR_INTERFACE_H
+
+#include <stdint.h>
+#include <sys/types.h>
+
+#include <utils/Singleton.h>
+
+#include <gui/Sensor.h>
+
+#include "SensorDevice.h"
+
+// ---------------------------------------------------------------------------
+
+namespace android {
+// ---------------------------------------------------------------------------
+
+class SensorInterface {
+public:
+    virtual ~SensorInterface();
+
+    virtual bool process(sensors_event_t* outEvent,
+            const sensors_event_t& event) = 0;
+
+    virtual bool isEnabled() const = 0;
+    virtual status_t activate(void* ident, bool enabled) = 0;
+    virtual status_t setDelay(void* ident, int handle, int64_t ns) = 0;
+    virtual Sensor getSensor() const = 0;
+    virtual bool isVirtual() const = 0;
+};
+
+// ---------------------------------------------------------------------------
+
+class HardwareSensor : public SensorInterface
+{
+    SensorDevice& mSensorDevice;
+    Sensor mSensor;
+    bool mEnabled;
+
+public:
+    HardwareSensor(const sensor_t& sensor);
+
+    virtual ~HardwareSensor();
+
+    virtual bool process(sensors_event_t* outEvent,
+            const sensors_event_t& event);
+
+    virtual bool isEnabled() const;
+    virtual status_t activate(void* ident, bool enabled);
+    virtual status_t setDelay(void* ident, int handle, int64_t ns);
+    virtual Sensor getSensor() const;
+    virtual bool isVirtual() const { return false; }
+};
+
+
+// ---------------------------------------------------------------------------
+}; // namespace android
+
+#endif // ANDROID_SENSOR_INTERFACE_H
diff --git a/services/sensorservice/SensorService.cpp b/services/sensorservice/SensorService.cpp
index 22a45df..ea5e5cc 100644
--- a/services/sensorservice/SensorService.cpp
+++ b/services/sensorservice/SensorService.cpp
@@ -15,6 +15,7 @@
  */
 
 #include <stdint.h>
+#include <math.h>
 #include <sys/types.h>
 
 #include <utils/SortedVector.h>
@@ -35,80 +36,15 @@
 #include <hardware/sensors.h>
 
 #include "SensorService.h"
+#include "GravitySensor.h"
+#include "LinearAccelerationSensor.h"
+#include "RotationVectorSensor.h"
 
 namespace android {
 // ---------------------------------------------------------------------------
 
-class BatteryService : public Singleton<BatteryService> {
-    static const int TRANSACTION_noteStartSensor = IBinder::FIRST_CALL_TRANSACTION + 3;
-    static const int TRANSACTION_noteStopSensor = IBinder::FIRST_CALL_TRANSACTION + 4;
-    static const String16 DESCRIPTOR;
-
-    friend class Singleton<BatteryService>;
-    sp<IBinder> mBatteryStatService;
-
-    BatteryService() {
-        const sp<IServiceManager> sm(defaultServiceManager());
-        if (sm != NULL) {
-            const String16 name("batteryinfo");
-            mBatteryStatService = sm->getService(name);
-        }
-    }
-
-    status_t noteStartSensor(int uid, int handle) {
-        Parcel data, reply;
-        data.writeInterfaceToken(DESCRIPTOR);
-        data.writeInt32(uid);
-        data.writeInt32(handle);
-        status_t err = mBatteryStatService->transact(
-                TRANSACTION_noteStartSensor, data, &reply, 0);
-        err = reply.readExceptionCode();
-        return err;
-    }
-
-    status_t noteStopSensor(int uid, int handle) {
-        Parcel data, reply;
-        data.writeInterfaceToken(DESCRIPTOR);
-        data.writeInt32(uid);
-        data.writeInt32(handle);
-        status_t err = mBatteryStatService->transact(
-                TRANSACTION_noteStopSensor, data, &reply, 0);
-        err = reply.readExceptionCode();
-        return err;
-    }
-
-public:
-    void enableSensor(int handle) {
-        if (mBatteryStatService != 0) {
-            int uid = IPCThreadState::self()->getCallingUid();
-            int64_t identity = IPCThreadState::self()->clearCallingIdentity();
-            noteStartSensor(uid, handle);
-            IPCThreadState::self()->restoreCallingIdentity(identity);
-        }
-    }
-    void disableSensor(int handle) {
-        if (mBatteryStatService != 0) {
-            int uid = IPCThreadState::self()->getCallingUid();
-            int64_t identity = IPCThreadState::self()->clearCallingIdentity();
-            noteStopSensor(uid, handle);
-            IPCThreadState::self()->restoreCallingIdentity(identity);
-        }
-    }
-};
-
-const String16 BatteryService::DESCRIPTOR("com.android.internal.app.IBatteryStats");
-
-ANDROID_SINGLETON_STATIC_INSTANCE(BatteryService)
-
-// ---------------------------------------------------------------------------
-
-// 100 events/s max
-static const nsecs_t MINIMUM_EVENT_PERIOD = ms2ns(10);
-
 SensorService::SensorService()
     : Thread(false),
-      mSensorDevice(0),
-      mSensorModule(0),
       mDump("android.permission.DUMP"),
       mInitCheck(NO_INIT)
 {
@@ -118,43 +54,66 @@
 {
     LOGD("nuSensorService starting...");
 
-    status_t err = hw_get_module(SENSORS_HARDWARE_MODULE_ID,
-            (hw_module_t const**)&mSensorModule);
+    SensorDevice& dev(SensorDevice::getInstance());
 
-    LOGE_IF(err, "couldn't load %s module (%s)",
-            SENSORS_HARDWARE_MODULE_ID, strerror(-err));
-
-    if (mSensorModule) {
-        err = sensors_open(&mSensorModule->common, &mSensorDevice);
-
-        LOGE_IF(err, "couldn't open device for module %s (%s)",
-                SENSORS_HARDWARE_MODULE_ID, strerror(-err));
-
-        sensors_event_t event;
-        memset(&event, 0, sizeof(event));
-
-        struct sensor_t const* list;
-        int count = mSensorModule->get_sensors_list(mSensorModule, &list);
+    if (dev.initCheck() == NO_ERROR) {
+        uint32_t virtualSensorsNeeds =
+                (1<<SENSOR_TYPE_GRAVITY) |
+                (1<<SENSOR_TYPE_LINEAR_ACCELERATION) |
+                (1<<SENSOR_TYPE_ROTATION_VECTOR);
+        sensor_t const* list;
+        int count = dev.getSensorList(&list);
         mLastEventSeen.setCapacity(count);
         for (int i=0 ; i<count ; i++) {
-            Sensor sensor(list + i);
-            LOGI("%s", sensor.getName().string());
-            mSensorList.add(sensor);
-            if (mSensorDevice) {
-                mSensorDevice->activate(mSensorDevice, sensor.getHandle(), 0);
+            registerSensor( new HardwareSensor(list[i]) );
+            switch (list[i].type) {
+                case SENSOR_TYPE_GRAVITY:
+                case SENSOR_TYPE_LINEAR_ACCELERATION:
+                case SENSOR_TYPE_ROTATION_VECTOR:
+                    virtualSensorsNeeds &= ~(1<<list[i].type);
+                    break;
             }
-            mLastEventSeen.add(sensor.getHandle(), event);
         }
 
-        if (mSensorDevice) {
-            run("SensorService", PRIORITY_URGENT_DISPLAY);
-            mInitCheck = NO_ERROR;
+        if (virtualSensorsNeeds & (1<<SENSOR_TYPE_GRAVITY)) {
+            registerVirtualSensor( new GravitySensor(list, count) );
         }
+        if (virtualSensorsNeeds & (1<<SENSOR_TYPE_LINEAR_ACCELERATION)) {
+            registerVirtualSensor( new LinearAccelerationSensor(list, count) );
+        }
+        if (virtualSensorsNeeds & (1<<SENSOR_TYPE_ROTATION_VECTOR)) {
+            registerVirtualSensor( new RotationVectorSensor(list, count) );
+        }
+
+        run("SensorService", PRIORITY_URGENT_DISPLAY);
+        mInitCheck = NO_ERROR;
     }
 }
 
+void SensorService::registerSensor(SensorInterface* s)
+{
+    sensors_event_t event;
+    memset(&event, 0, sizeof(event));
+
+    const Sensor sensor(s->getSensor());
+    // add to the sensor list (returned to clients)
+    mSensorList.add(sensor);
+    // add to our handle->SensorInterface mapping
+    mSensorMap.add(sensor.getHandle(), s);
+    // create an entry in the mLastEventSeen array
+    mLastEventSeen.add(sensor.getHandle(), event);
+}
+
+void SensorService::registerVirtualSensor(SensorInterface* s)
+{
+    registerSensor(s);
+    mVirtualSensorList.add( s );
+}
+
 SensorService::~SensorService()
 {
+    for (size_t i=0 ; i<mSensorMap.size() ; i++)
+        delete mSensorMap.valueAt(i);
 }
 
 status_t SensorService::dump(int fd, const Vector<String16>& args)
@@ -175,7 +134,7 @@
         for (size_t i=0 ; i<mSensorList.size() ; i++) {
             const Sensor& s(mSensorList[i]);
             const sensors_event_t& e(mLastEventSeen.valueFor(s.getHandle()));
-            snprintf(buffer, SIZE, "%s (vendor=%s, handle=%d, maxRate=%.2fHz, last=<%5.1f,%5.1f,%5.1f>)\n",
+            snprintf(buffer, SIZE, "%-48s| %-32s | 0x%08x | maxRate=%7.2fHz | last=<%5.1f,%5.1f,%5.1f>\n",
                     s.getName().string(),
                     s.getVendor().string(),
                     s.getHandle(),
@@ -183,6 +142,7 @@
                     e.data[0], e.data[1], e.data[2]);
             result.append(buffer);
         }
+        SensorDevice::getInstance().dump(result, buffer, SIZE);
 
         snprintf(buffer, SIZE, "%d active connections\n",
                 mActiveConnections.size());
@@ -191,7 +151,7 @@
         result.append(buffer);
         for (size_t i=0 ; i<mActiveSensors.size() ; i++) {
             int handle = mActiveSensors.keyAt(i);
-            snprintf(buffer, SIZE, "%s (handle=%d, connections=%d)\n",
+            snprintf(buffer, SIZE, "%s (handle=0x%08x, connections=%d)\n",
                     getSensorName(handle).string(),
                     handle,
                     mActiveSensors.valueAt(i)->getNumConnections());
@@ -206,13 +166,15 @@
 {
     LOGD("nuSensorService thread starting...");
 
-    sensors_event_t buffer[16];
-    sensors_event_t scratch[16];
-    struct sensors_poll_device_t* device = mSensorDevice;
-    ssize_t count;
+    const size_t numEventMax = 16 * (1 + mVirtualSensorList.size());
+    sensors_event_t buffer[numEventMax];
+    sensors_event_t scratch[numEventMax];
+    SensorDevice& device(SensorDevice::getInstance());
+    const size_t vcount = mVirtualSensorList.size();
 
+    ssize_t count;
     do {
-        count = device->poll(device, buffer, sizeof(buffer)/sizeof(*buffer));
+        count = device.poll(buffer, numEventMax);
         if (count<0) {
             LOGE("sensor poll failed (%s)", strerror(-count));
             break;
@@ -220,19 +182,44 @@
 
         recordLastValue(buffer, count);
 
-        const SortedVector< wp<SensorEventConnection> > activeConnections(
-                getActiveConnections());
-
-        size_t numConnections = activeConnections.size();
-        if (numConnections) {
-            for (size_t i=0 ; i<numConnections ; i++) {
-                sp<SensorEventConnection> connection(activeConnections[i].promote());
-                if (connection != 0) {
-                    connection->sendEvents(buffer, count, scratch);
+        // handle virtual sensors
+        if (count && vcount) {
+            const DefaultKeyedVector<int, SensorInterface*> virtualSensors(
+                    getActiveVirtualSensors());
+            const size_t activeVirtualSensorCount = virtualSensors.size();
+            if (activeVirtualSensorCount) {
+                size_t k = 0;
+                for (size_t i=0 ; i<size_t(count) ; i++) {
+                    sensors_event_t const * const event = buffer;
+                    for (size_t j=0 ; j<activeVirtualSensorCount ; j++) {
+                        sensors_event_t out;
+                        if (virtualSensors.valueAt(j)->process(&out, event[i])) {
+                            buffer[count + k] = out;
+                            k++;
+                        }
+                    }
+                }
+                if (k) {
+                    // record the last synthesized values
+                    recordLastValue(&buffer[count], k);
+                    count += k;
+                    // sort the buffer by time-stamps
+                    sortEventBuffer(buffer, count);
                 }
             }
         }
 
+        // send our events to clients...
+        const SortedVector< wp<SensorEventConnection> > activeConnections(
+                getActiveConnections());
+        size_t numConnections = activeConnections.size();
+        for (size_t i=0 ; i<numConnections ; i++) {
+            sp<SensorEventConnection> connection(
+                    activeConnections[i].promote());
+            if (connection != 0) {
+                connection->sendEvents(buffer, count, scratch);
+            }
+        }
     } while (count >= 0 || Thread::exitPending());
 
     LOGW("Exiting SensorService::threadLoop!");
@@ -257,6 +244,18 @@
     mLastEventSeen.editValueFor(prev) = buffer[count-1];
 }
 
+void SensorService::sortEventBuffer(sensors_event_t* buffer, size_t count)
+{
+    struct compar {
+        static int cmp(void const* lhs, void const* rhs) {
+            sensors_event_t const* l = static_cast<sensors_event_t const*>(lhs);
+            sensors_event_t const* r = static_cast<sensors_event_t const*>(rhs);
+            return r->timestamp - l->timestamp;
+        }
+    };
+    qsort(buffer, count, sizeof(sensors_event_t), compar::cmp);
+}
+
 SortedVector< wp<SensorService::SensorEventConnection> >
 SensorService::getActiveConnections() const
 {
@@ -264,6 +263,13 @@
     return mActiveConnections;
 }
 
+DefaultKeyedVector<int, SensorInterface*>
+SensorService::getActiveVirtualSensors() const
+{
+    Mutex::Autolock _l(mLock);
+    return mActiveVirtualSensors;
+}
+
 String8 SensorService::getSensorName(int handle) const {
     size_t count = mSensorList.size();
     for (size_t i=0 ; i<count ; i++) {
@@ -294,8 +300,13 @@
     for (size_t i=0 ; i<size ; ) {
         SensorRecord* rec = mActiveSensors.valueAt(i);
         if (rec && rec->removeConnection(connection)) {
-            mSensorDevice->activate(mSensorDevice, mActiveSensors.keyAt(i), 0);
+            int handle = mActiveSensors.keyAt(i);
+            SensorInterface* sensor = mSensorMap.valueFor( handle );
+            if (sensor) {
+                sensor->activate(connection.unsafe_get(), false);
+            }
             mActiveSensors.removeItemsAt(i, 1);
+            mActiveVirtualSensors.removeItem(handle);
             delete rec;
             size--;
         } else {
@@ -311,39 +322,38 @@
     if (mInitCheck != NO_ERROR)
         return mInitCheck;
 
-    status_t err = NO_ERROR;
     Mutex::Autolock _l(mLock);
-    SensorRecord* rec = mActiveSensors.valueFor(handle);
-    if (rec == 0) {
-        rec = new SensorRecord(connection);
-        mActiveSensors.add(handle, rec);
-        err = mSensorDevice->activate(mSensorDevice, handle, 1);
-        LOGE_IF(err, "Error activating sensor %d (%s)", handle, strerror(-err));
-        if (err == 0) {
-            BatteryService::getInstance().enableSensor(handle);
-        }
-    } else {
-        if (rec->addConnection(connection)) {
-            // this sensor is already activated, but we are adding a
-            // connection that uses it. Immediately send down the last
-            // known value of the requested sensor.
-            sensors_event_t scratch;
-            sensors_event_t& event(mLastEventSeen.editValueFor(handle));
-            if (event.version == sizeof(sensors_event_t)) {
-                connection->sendEvents(&event, 1);
-            }
-        }
-    }
+    SensorInterface* sensor = mSensorMap.valueFor(handle);
+    status_t err = sensor ? sensor->activate(connection.get(), true) : status_t(BAD_VALUE);
     if (err == NO_ERROR) {
-        // connection now active
-        if (connection->addSensor(handle)) {
-            // the sensor was added (which means it wasn't already there)
-            // so, see if this connection becomes active
-            if (mActiveConnections.indexOf(connection) < 0) {
-                mActiveConnections.add(connection);
+        SensorRecord* rec = mActiveSensors.valueFor(handle);
+        if (rec == 0) {
+            rec = new SensorRecord(connection);
+            mActiveSensors.add(handle, rec);
+            if (sensor->isVirtual()) {
+                mActiveVirtualSensors.add(handle, sensor);
             }
-            // this could change the sensor event delivery speed
-            recomputeEventsPeriodLocked(handle);
+        } else {
+            if (rec->addConnection(connection)) {
+                // this sensor is already activated, but we are adding a
+                // connection that uses it. Immediately send down the last
+                // known value of the requested sensor.
+                sensors_event_t scratch;
+                sensors_event_t& event(mLastEventSeen.editValueFor(handle));
+                if (event.version == sizeof(sensors_event_t)) {
+                    connection->sendEvents(&event, 1);
+                }
+            }
+        }
+        if (err == NO_ERROR) {
+            // connection now active
+            if (connection->addSensor(handle)) {
+                // the sensor was added (which means it wasn't already there)
+                // so, see if this connection becomes active
+                if (mActiveConnections.indexOf(connection) < 0) {
+                    mActiveConnections.add(connection);
+                }
+            }
         }
     }
     return err;
@@ -367,15 +377,11 @@
         // see if this sensor becomes inactive
         if (rec->removeConnection(connection)) {
             mActiveSensors.removeItem(handle);
+            mActiveVirtualSensors.removeItem(handle);
             delete rec;
-            err = mSensorDevice->activate(mSensorDevice, handle, 0);
-            if (err == 0) {
-                BatteryService::getInstance().disableSensor(handle);
-            }
         }
-    }
-    if (err == NO_ERROR) {
-        recomputeEventsPeriodLocked(handle);
+        SensorInterface* sensor = mSensorMap.valueFor(handle);
+        err = sensor ? sensor->activate(connection.get(), false) : status_t(BAD_VALUE);
     }
     return err;
 }
@@ -392,30 +398,9 @@
     if (ns < MINIMUM_EVENTS_PERIOD)
         ns = MINIMUM_EVENTS_PERIOD;
 
-    Mutex::Autolock _l(mLock);
-    status_t err = connection->setEventRateLocked(handle, ns);
-    if (err == NO_ERROR) {
-        recomputeEventsPeriodLocked(handle);
-    }
-    return err;
-}
-
-status_t SensorService::recomputeEventsPeriodLocked(int32_t handle)
-{
-    status_t err = NO_ERROR;
-    nsecs_t wanted = ms2ns(1000);
-    size_t count = mActiveConnections.size();
-    for (size_t i=0 ; i<count ; i++) {
-        sp<SensorEventConnection> connection(mActiveConnections[i].promote());
-        if (connection != NULL) {
-            nsecs_t ns = connection->getEventRateForSensor(handle);
-            if (ns) {
-                wanted = wanted < ns ? wanted : ns;
-            }
-        }
-    }
-    err = mSensorDevice->setDelay(mSensorDevice, handle, wanted);
-    return err;
+    SensorInterface* sensor = mSensorMap.valueFor(handle);
+    if (!sensor) return BAD_VALUE;
+    return sensor->setDelay(connection.get(), handle, ns);
 }
 
 // ---------------------------------------------------------------------------
@@ -465,9 +450,8 @@
 
 bool SensorService::SensorEventConnection::addSensor(int32_t handle) {
     Mutex::Autolock _l(mConnectionLock);
-    if (mSensorInfo.indexOfKey(handle) <= 0) {
-        SensorInfo info;
-        mSensorInfo.add(handle, info);
+    if (mSensorInfo.indexOf(handle) <= 0) {
+        mSensorInfo.add(handle);
         return true;
     }
     return false;
@@ -475,7 +459,7 @@
 
 bool SensorService::SensorEventConnection::removeSensor(int32_t handle) {
     Mutex::Autolock _l(mConnectionLock);
-    if (mSensorInfo.removeItem(handle) >= 0) {
+    if (mSensorInfo.remove(handle) >= 0) {
         return true;
     }
     return false;
@@ -483,7 +467,7 @@
 
 bool SensorService::SensorEventConnection::hasSensor(int32_t handle) const {
     Mutex::Autolock _l(mConnectionLock);
-    return mSensorInfo.indexOfKey(handle) >= 0;
+    return mSensorInfo.indexOf(handle) >= 0;
 }
 
 bool SensorService::SensorEventConnection::hasAnySensor() const {
@@ -491,19 +475,6 @@
     return mSensorInfo.size() ? true : false;
 }
 
-status_t SensorService::SensorEventConnection::setEventRateLocked(
-        int handle, nsecs_t ns)
-{
-    Mutex::Autolock _l(mConnectionLock);
-    ssize_t index = mSensorInfo.indexOfKey(handle);
-    if (index >= 0) {
-        SensorInfo& info = mSensorInfo.editValueFor(handle);
-        info.ns = ns;
-        return NO_ERROR;
-    }
-    return status_t(index);
-}
-
 status_t SensorService::SensorEventConnection::sendEvents(
         sensors_event_t const* buffer, size_t numEvents,
         sensors_event_t* scratch)
@@ -515,7 +486,7 @@
         size_t i=0;
         while (i<numEvents) {
             const int32_t curr = buffer[i].sensor;
-            if (mSensorInfo.indexOfKey(curr) >= 0) {
+            if (mSensorInfo.indexOf(curr) >= 0) {
                 do {
                     scratch[count++] = buffer[i++];
                 } while ((i<numEvents) && (buffer[i].sensor == curr));
diff --git a/services/sensorservice/SensorService.h b/services/sensorservice/SensorService.h
index c0922f5..540c7e2 100644
--- a/services/sensorservice/SensorService.h
+++ b/services/sensorservice/SensorService.h
@@ -34,6 +34,8 @@
 #include <gui/ISensorServer.h>
 #include <gui/ISensorEventConnection.h>
 
+#include "SensorInterface.h"
+
 // ---------------------------------------------------------------------------
 
 struct sensors_poll_device_t;
@@ -50,7 +52,6 @@
    friend class BinderService<SensorService>;
 
    static const nsecs_t MINIMUM_EVENTS_PERIOD =   1000000; // 1000 Hz
-   static const nsecs_t DEFAULT_EVENTS_PERIOD = 200000000; //    5 Hz
 
             SensorService();
     virtual ~SensorService();
@@ -77,12 +78,8 @@
         sp<SensorChannel> const mChannel;
         mutable Mutex mConnectionLock;
 
-        // protected mConnectionLock
-        struct SensorInfo {
-            SensorInfo() : ns(DEFAULT_EVENTS_PERIOD) { }
-            nsecs_t ns;
-        };
-        DefaultKeyedVector<int32_t, SensorInfo> mSensorInfo;
+        // protected by SensorService::mLock
+        SortedVector<int> mSensorInfo;
 
     public:
         SensorEventConnection(const sp<SensorService>& service);
@@ -93,10 +90,6 @@
         bool hasAnySensor() const;
         bool addSensor(int32_t handle);
         bool removeSensor(int32_t handle);
-        status_t setEventRateLocked(int handle, nsecs_t ns);
-        nsecs_t getEventRateForSensor(int32_t handle) const {
-            return mSensorInfo.valueFor(handle).ns;
-        }
     };
 
     class SensorRecord {
@@ -109,21 +102,25 @@
     };
 
     SortedVector< wp<SensorEventConnection> > getActiveConnections() const;
-    String8 getSensorName(int handle) const;
-    status_t recomputeEventsPeriodLocked(int32_t handle);
+    DefaultKeyedVector<int, SensorInterface*> getActiveVirtualSensors() const;
 
+    String8 getSensorName(int handle) const;
     void recordLastValue(sensors_event_t const * buffer, size_t count);
+    static void sortEventBuffer(sensors_event_t* buffer, size_t count);
+    void registerSensor(SensorInterface* sensor);
+    void registerVirtualSensor(SensorInterface* sensor);
 
     // constants
     Vector<Sensor> mSensorList;
-    struct sensors_poll_device_t* mSensorDevice;
-    struct sensors_module_t* mSensorModule;
+    DefaultKeyedVector<int, SensorInterface*> mSensorMap;
+    Vector<SensorInterface *> mVirtualSensorList;
     Permission mDump;
     status_t mInitCheck;
 
     // protected by mLock
     mutable Mutex mLock;
     DefaultKeyedVector<int, SensorRecord*> mActiveSensors;
+    DefaultKeyedVector<int, SensorInterface*> mActiveVirtualSensors;
     SortedVector< wp<SensorEventConnection> > mActiveConnections;
 
     // The size of this vector is constant, only the items are mutable