Diff: services/HealthThermometerService.h

Revision:

118:620d28e7a1ba

Child:

237:448f29f4ae7f

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/services/HealthThermometerService.h	Mon Sep 22 10:59:09 2014 +0100
@@ -0,0 +1,131 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2013 ARM Limited
+ *
+ * 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 __BLE_HEALTH_THERMOMETER_SERVICE_H__
+#define __BLE_HEALTH_THERMOMETER_SERVICE_H__
+
+#include "BLEDevice.h"
+
+/* Health Thermometer Service */
+/* Service:  https://developer.bluetooth.org/gatt/profiles/Pages/ProfileViewer.aspx?u=org.bluetooth.profile.health_thermometer.xml */
+/* Temperature Measurement: https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.temperature_measurement.xml */
+/* Temperature Type: https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.temperature_type.xml */
+class HealthThermometerService {
+public:
+    enum {
+        LOCATION_ARMPIT = 1,
+        LOCATION_BODY,
+        LOCATION_EAR,
+        LOCATION_FINGER,
+        LOCATION_GI_TRACT,
+        LOCATION_MOUTH,
+        LOCATION_RECTUM,
+        LOCATION_TOE,
+        LOCATION_EAR_DRUM,
+    };
+
+public:
+
+    /**
+     * @param[in] _ble         reference to the BLE device
+     * @param[in] initialTemp  initial value in celsius
+     * @param[in] _location
+     */
+    HealthThermometerService(BLEDevice &_ble, float initialTemp, uint8_t _location) :
+        ble(_ble),
+        valueBytes(initialTemp),
+        tempMeasurement(GattCharacteristic::UUID_TEMPERATURE_MEASUREMENT_CHAR, valueBytes.getPointer(),
+                        sizeof(TemperatureValueBytes), sizeof(TemperatureValueBytes),
+                        GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ | GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_NOTIFY),
+        tempLocation(GattCharacteristic::UUID_TEMPERATURE_TYPE_CHAR, (uint8_t *)&_location, sizeof(_location), sizeof(_location),
+                     GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_READ) {
+
+        GattCharacteristic *hrmChars[] = {&tempMeasurement, &tempLocation, };
+        GattService         hrmService(GattService::UUID_HEALTH_THERMOMETER_SERVICE, hrmChars, sizeof(hrmChars) / sizeof(GattCharacteristic *));
+
+        ble.addService(hrmService);
+    }
+
+    void updateTemperature(float temperature) {
+        if (ble.getGapState().connected) {
+            valueBytes.updateTemperature(temperature);
+            ble.updateCharacteristicValue(tempMeasurement.getValueAttribute().getHandle(), valueBytes.getPointer(), sizeof(TemperatureValueBytes));
+        }
+    }
+
+private:
+    /* Private internal representation for the bytes used to work with the vaulue of the heart-rate characteristic. */
+    struct TemperatureValueBytes {
+        static const unsigned OFFSET_OF_FLAGS    = 0;
+        static const unsigned OFFSET_OF_VALUE    = OFFSET_OF_FLAGS + sizeof(uint8_t);
+        static const unsigned SIZEOF_VALUE_BYTES = sizeof(uint8_t) + sizeof(float);
+
+        static const unsigned TEMPERATURE_UNITS_FLAG_POS = 0;
+        static const unsigned TIMESTAMP_FLAG_POS         = 1;
+        static const unsigned TEMPERATURE_TYPE_FLAG_POS  = 2;
+
+        static const uint8_t TEMPERATURE_UNITS_CELSIUS    = 0;
+        static const uint8_t TEMPERATURE_UNITS_FAHRENHEIT = 1;
+
+        TemperatureValueBytes(float initialTemperature) : bytes() {
+            /* assumption: temperature values are expressed in Celsius */
+            bytes[OFFSET_OF_FLAGS] =  (TEMPERATURE_UNITS_CELSIUS << TEMPERATURE_UNITS_FLAG_POS) |
+                                      (false << TIMESTAMP_FLAG_POS) |
+                                      (false << TEMPERATURE_TYPE_FLAG_POS);
+            updateTemperature(initialTemperature);
+        }
+
+        void updateTemperature(float temp) {
+            uint32_t temp_ieee11073 = quick_ieee11073_from_float(temp);
+            memcpy(&bytes[OFFSET_OF_VALUE], &temp_ieee11073, sizeof(float));
+        }
+
+        uint8_t *getPointer(void) {
+            return bytes;
+        }
+
+        const uint8_t *getPointer(void) const {
+            return bytes;
+        }
+
+    private:
+        /**
+         * @brief A very quick conversion between a float temperature and 11073-20601 FLOAT-Type.
+         * @param temperature The temperature as a float.
+         * @return The temperature in 11073-20601 FLOAT-Type format.
+         */
+        uint32_t quick_ieee11073_from_float(float temperature) {
+            uint8_t  exponent = 0xFE; //exponent is -2
+            uint32_t mantissa = (uint32_t)(temperature * 100);
+
+            return (((uint32_t)exponent) << 24) | mantissa;
+        }
+
+
+    private:
+        /* First byte = 8-bit flags, Second field is a float holding the temperature value. */
+        /* See --> https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.temperature_measurement.xml */
+        uint8_t bytes[SIZEOF_VALUE_BYTES];
+    };
+
+private:
+    BLEDevice             &ble;
+    TemperatureValueBytes  valueBytes;
+    GattCharacteristic     tempMeasurement;
+    GattCharacteristic     tempLocation;
+};
+
+#endif /* #ifndef __BLE_HEALTH_THERMOMETER_SERVICE_H__*/