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HealthThermometerService.h
1 /* mbed Microcontroller Library
2  * Copyright (c) 2006-2020 ARM Limited
3  *
4  * SPDX-License-Identifier: Apache-2.0
5  *
6  * Licensed under the Apache License, Version 2.0 (the "License");
7  * you may not use this file except in compliance with the License.
8  * You may obtain a copy of the License at
9  *
10  * http://www.apache.org/licenses/LICENSE-2.0
11  *
12  * Unless required by applicable law or agreed to in writing, software
13  * distributed under the License is distributed on an "AS IS" BASIS,
14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15  * See the License for the specific language governing permissions and
16  * limitations under the License.
17  */
18 
19 /* MBED_DEPRECATED */
20 #warning "These services are deprecated and will be removed. Please see services.md for details about replacement services."
21 
22 #ifndef __BLE_HEALTH_THERMOMETER_SERVICE_H__
23 #define __BLE_HEALTH_THERMOMETER_SERVICE_H__
24 
25 #include "ble/BLE.h"
26 #include "ble/Gap.h"
27 #include "ble/GattServer.h"
28 
29 #if BLE_FEATURE_GATT_SERVER
30 
31 /**
32 * @class HealthThermometerService
33 * @brief BLE Health Thermometer Service. This service provides the location of the thermometer and the temperature.
34 * Service: https://developer.bluetooth.org/gatt/profiles/Pages/ProfileViewer.aspx?u=org.bluetooth.profile.health_thermometer.xml
35 * Temperature Measurement: https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.temperature_measurement.xml
36 * Temperature Type: https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.temperature_type.xml
37 */
39 public:
40  /**
41  * @brief Location of sensor on the body.
42  */
44  LOCATION_ARMPIT = 1, /*!< Armpit. */
45  LOCATION_BODY, /*!< Body. */
46  LOCATION_EAR, /*!< Ear. */
47  LOCATION_FINGER, /*!< Finger. */
48  LOCATION_GI_TRACT, /*!< GI tract */
49  LOCATION_MOUTH, /*!< Mouth. */
50  LOCATION_RECTUM, /*!< Rectum. */
51  LOCATION_TOE, /*!< Toe. */
52  LOCATION_EAR_DRUM, /*!< Eardrum. */
53  };
54 
55 public:
56  /**
57  * @brief Add the Health Thermometer Service to an existing BLE object, initialize with temperature and location.
58  * @param[in] _ble Reference to the BLE device.
59  * @param[in] initialTemp Initial value in celsius.
60  * @param[in] _location
61  */
62  HealthThermometerService(BLE &_ble, float initialTemp, uint8_t _location) :
63  ble(_ble),
64  valueBytes(initialTemp),
65  tempMeasurement(GattCharacteristic::UUID_TEMPERATURE_MEASUREMENT_CHAR, (TemperatureValueBytes *)valueBytes.getPointer(), GattCharacteristic::BLE_GATT_CHAR_PROPERTIES_INDICATE),
66  tempLocation(GattCharacteristic::UUID_TEMPERATURE_TYPE_CHAR, &_location) {
67 
68  GattCharacteristic *hrmChars[] = {&tempMeasurement, &tempLocation, };
69  GattService hrmService(GattService::UUID_HEALTH_THERMOMETER_SERVICE, hrmChars, sizeof(hrmChars) / sizeof(hrmChars[0]));
70 
71  ble.gattServer().addService(hrmService);
72  }
73 
74  /**
75  * @brief Update the temperature being broadcast.
76  *
77  * @param[in] temperature
78  * Floating point value of the temperature.
79  *
80  */
81  void updateTemperature(float temperature) {
82  valueBytes.updateTemperature(temperature);
83  ble.gattServer().write(tempMeasurement.getValueHandle(), valueBytes.getPointer(), sizeof(TemperatureValueBytes));
84  }
85 
86  /**
87  * @brief Update the location.
88  * @param loc
89  * New location value.
90  */
92  ble.gattServer().write(tempLocation.getValueHandle(), reinterpret_cast<uint8_t *>(&loc), sizeof(uint8_t));
93  }
94 
95 private:
96  /* Private internal representation for the bytes used to work with the vaulue of the temperature characteristic. */
97  struct TemperatureValueBytes {
98  static const unsigned OFFSET_OF_FLAGS = 0;
99  static const unsigned OFFSET_OF_VALUE = OFFSET_OF_FLAGS + sizeof(uint8_t);
100  static const unsigned SIZEOF_VALUE_BYTES = sizeof(uint8_t) + sizeof(float);
101 
102  static const unsigned TEMPERATURE_UNITS_FLAG_POS = 0;
103  static const unsigned TIMESTAMP_FLAG_POS = 1;
104  static const unsigned TEMPERATURE_TYPE_FLAG_POS = 2;
105 
106  static const uint8_t TEMPERATURE_UNITS_CELSIUS = 0;
107  static const uint8_t TEMPERATURE_UNITS_FAHRENHEIT = 1;
108 
109  TemperatureValueBytes(float initialTemperature) : bytes() {
110  /* Assumption: temperature values are expressed in celsius */
111  bytes[OFFSET_OF_FLAGS] = (TEMPERATURE_UNITS_CELSIUS << TEMPERATURE_UNITS_FLAG_POS) |
112  (false << TIMESTAMP_FLAG_POS) |
113  (false << TEMPERATURE_TYPE_FLAG_POS);
114  updateTemperature(initialTemperature);
115  }
116 
117  void updateTemperature(float temp) {
118  uint32_t temp_ieee11073 = quick_ieee11073_from_float(temp);
119  memcpy(&bytes[OFFSET_OF_VALUE], &temp_ieee11073, sizeof(float));
120  }
121 
122  uint8_t *getPointer() {
123  return bytes;
124  }
125 
126  const uint8_t *getPointer() const {
127  return bytes;
128  }
129 
130 private:
131  /**
132  * @brief A very quick conversion between a float temperature and 11073-20601 FLOAT-Type.
133  * @param temperature The temperature as a float.
134  * @return The temperature in 11073-20601 FLOAT-Type format.
135  */
136  static uint32_t quick_ieee11073_from_float(float temperature) {
137  uint8_t exponent = 0xFE; //Exponent is -2
138  uint32_t mantissa = (uint32_t)(temperature * 100);
139 
140  return (((uint32_t)exponent) << 24) | mantissa;
141  }
142 
143 private:
144  /* First byte: 8-bit flags. Second field is a float holding the temperature value. */
145  /* See https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.temperature_measurement.xml */
146  uint8_t bytes[SIZEOF_VALUE_BYTES];
147  };
148 
149 protected:
150  BLE &ble;
151  TemperatureValueBytes valueBytes;
154 };
155 
156 #endif // BLE_FEATURE_GATT_SERVER
157 
158 #endif /* #ifndef __BLE_HEALTH_THERMOMETER_SERVICE_H__*/
void updateTemperature(float temperature)
Update the temperature being broadcast.
UUID of the health thermometer.
GattAttribute::Handle_t getValueHandle() const
Get the characteristic&#39;s value attribute handle in the ATT table.
SensorLocation_t
Location of sensor on the body.
BLE Health Thermometer Service.
Representation of a GattServer characteristic.
void updateLocation(SensorLocation_t loc)
Update the location.
Representation of a GattServer service.
Entry namespace for all BLE API definitions.
Abstract away BLE-capable radio transceivers or SOCs.
Definition: BLE.h:137
HealthThermometerService(BLE &_ble, float initialTemp, uint8_t _location)
Add the Health Thermometer Service to an existing BLE object, initialize with temperature and locatio...
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