【Curie Nano试用】 A3.模拟心率计学习

limale

这两天抽空玩了一下Curie Nano，如果不考虑它的定位可以直接当成arduino nano来使用的，并且性能更强大。
比如有更大的flash和ram：

灵活的供电方式，调试的时候可以直接通道microUSB接口进行供电。因为板子上自带升压电路也可以通道锂电池进行供电，专门为可穿戴的场合而设计。

而且IO也多达20个，所有的IO口都支持外部中断，最大20mA的驱动能力，这些都是以往的arduino板卡所不具备的特性。

因为这块intel的MCU集成了BLE4.0，所以迫不及待的先来测试一下。
蓝牙模块也用过，不过都是直接当串口来用，相当于有线转无线。这两天跟着官方的这篇心率计的教程https://www.arduino.cc/en/Tutorial/Genuino101CurieBLEHeartRateMonitor看了看，了解了BLE的连接关系和服务关系，还有GATT通用属性协议、profile、service、characteristic、UUID等，涉及的东西还是蛮多的。
相关的资料可以从这里找到：https://www.bluetooth.com/specifications/gatt
如果只看还是有点云里雾里的，我们直接来动手实现这个例子。
我们需要准备的东西有：Curie Nano、电位器或者别的模拟传感器、nRF Toolbox for BLE APP
no.nordicsemi.android.nrftoolbox.apk.zip (4.74 MB, 下载次数: 1)

2017-5-8 20:52 上传

点击文件名下载附件

1. <font size="4"><font size="4">/*
   
2.    Copyright (c) 2015 Intel Corporation.  All rights reserved.
   
3. 
   
4.    This library is free software; you can redistribute it and/or
   
5.    modify it under the terms of the GNU Lesser General Public
   
6.    License as published by the Free Software Foundation; either
   
7.    version 2.1 of the License, or (at your option) any later version.
   
8. 
   
9.    This library is distributed in the hope that it will be useful,
   
10.    but WITHOUT ANY WARRANTY; without even the implied warranty of
    
11.    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    
12.    Lesser General Public License for more details.
    
13. 
    
14.    You should have received a copy of the GNU Lesser General Public
    
15.    License along with this library; if not, write to the Free Software
    
16.    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
    
17. */
    
18. 
    
19. /*
    
20.    This sketch example partially implements the standard Bluetooth Low-Energy Heart Rate service.
    
21.    For more information: https://developer.bluetooth.org/gatt/services/Pages/ServicesHome.aspx
    
22. */
    
23. 
    
24. #include <CurieBLE.h>
    
25. 
    
26. BLEPeripheral blePeripheral;       // BLE Peripheral Device (the board you're programming)
    
27. BLEService heartRateService("180D"); // BLE Heart Rate Service
    
28. 
    
29. // BLE Heart Rate Measurement Characteristic"
    
30. BLECharacteristic heartRateChar("2A37",  // standard 16-bit characteristic UUID
    
31.     BLERead | BLENotify, 2);  // remote clients will be able to get notifications if this characteristic changes
    
32.                               // the characteristic is 2 bytes long as the first field needs to be "Flags" as per BLE specifications
    
33.                               // https://developer.bluetooth.org/gatt/characteristics/Pages/CharacteristicViewer.aspx?u=org.bluetooth.characteristic.heart_rate_measurement.xml
    
34. 
    
35. int oldHeartRate = 0;  // last heart rate reading from analog input
    
36. long previousMillis = 0;  // last time the heart rate was checked, in ms
    
37. 
    
38. void setup() {
    
39.   Serial.begin(9600);    // initialize serial communication
    
40.   pinMode(13, OUTPUT);   // initialize the LED on pin 13 to indicate when a central is connected
    
41. 
    
42.   /* Set a local name for the BLE device
    
43.      This name will appear in advertising packets
    
44.      and can be used by remote devices to identify this BLE device
    
45.      The name can be changed but maybe be truncated based on space left in advertisement packet */
    
46.   blePeripheral.setLocalName("HeartRateSketch");
    
47.   blePeripheral.setAdvertisedServiceUuid(heartRateService.uuid());  // add the service UUID
    
48.   blePeripheral.addAttribute(heartRateService);   // Add the BLE Heart Rate service
    
49.   blePeripheral.addAttribute(heartRateChar); // add the Heart Rate Measurement characteristic
    
50. 
    
51.   /* Now activate the BLE device.  It will start continuously transmitting BLE
    
52.      advertising packets and will be visible to remote BLE central devices
    
53.      until it receives a new connection */
    
54.   blePeripheral.begin();
    
55.   Serial.println("Bluetooth device active, waiting for connections...");
    
56. }
    
57. 
    
58. void loop() {
    
59.   // listen for BLE peripherals to connect:
    
60.   BLECentral central = blePeripheral.central();
    
61. 
    
62.   // if a central is connected to peripheral:
    
63.   if (central) {
    
64.     Serial.print("Connected to central: ");
    
65.     // print the central's MAC address:
    
66.     Serial.println(central.address());
    
67.     // turn on the LED to indicate the connection:
    
68.     digitalWrite(13, HIGH);
    
69. 
    
70.     // check the heart rate measurement every 200ms
    
71.     // as long as the central is still connected:
    
72.     while (central.connected()) {
    
73.       long currentMillis = millis();
    
74.       // if 200ms have passed, check the heart rate measurement:
    
75.       if (currentMillis - previousMillis >= 200) {
    
76.         previousMillis = currentMillis;
    
77.         updateHeartRate();
    
78.       }
    
79.     }
    
80.     // when the central disconnects, turn off the LED:
    
81.     digitalWrite(13, LOW);
    
82.     Serial.print("Disconnected from central: ");
    
83.     Serial.println(central.address());
    
84.   }
    
85. }
    
86. 
    
87. void updateHeartRate() {
    
88.   /* Read the current voltage level on the A0 analog input pin.
    
89.      This is used here to simulate the heart rate's measurement.
    
90.   */
    
91.   int heartRateMeasurement = analogRead(A0);
    
92.   int heartRate = map(heartRateMeasurement, 0, 1023, 0, 100);
    
93.   if (heartRate != oldHeartRate) {      // if the heart rate has changed
    
94.     Serial.print("Heart Rate is now: "); // print it
    
95.     Serial.println(heartRate);
    
96.     const unsigned char heartRateCharArray[2] = { 0, (char)heartRate };
    
97.     heartRateChar.setValue(heartRateCharArray, 2);  // and update the heart rate measurement characteristic
    
98.     oldHeartRate = heartRate;           // save the level for next comparison
    
99.   }
    
100. }</font></font>

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然后上传以上的代码到Curie Nano中，程序的实现主要是初始化BLE为外围设备然后手机就可以连接它了，下来增加心率服务，增加心率测量特征字，发送的数据包括两部分，flag位和数据位。这里我们设置为8位数据格式。然后通道A0口读取电位器的值进行转化之后就可以进行发送了。
然后我们nRF Toolbox APP 选择HRM图标进行连接，连接成功之后可以看到板载的指示灯亮了，对应的我们旋转电位器可以看到模拟的心率数据在变化了。如果断开连接，对应的指示灯也会熄灭。


通过以上例子的学习大概了解了BLE通讯的机制，下来再深入的进行学习吧。