1. #include <Wire.h>
2. #include <BLEDevice.h>
3. #include <BLEServer.h>
4. #include <BLEUtils.h>
5. #include <BLE2902.h>
6. #define I2C_SDA 21 // Nuncuck SDA
7. #define I2C_CLK 22 // Nuncuck CLK
8. BLECharacteristic *pCharacteristic;
9. bool deviceConnected = false;
11. uint8_t nunbuff[10]; // array to store ESP output
12. int cnt = 0;
13. int x_dat = 0; // 1byte Data
14. int y_dat = 0; // 1byte Data
15. int z_dat = 0; // 1byte Data
17. #define SERVICE_UUID "cdb068be-4458-11e9-b210-d663bd873d93"
18. #define CHARACTERISTIC_UUID "cdb06c10-4458-11e9-b210-d663bd873d93"
19. #define DEVICE_NAME "esp32_BLE"
21. class MyServerCallbacks: public BLEServerCallbacks {
22.     void onConnect(BLEServer* pServer) {
23.       deviceConnected = true;
24.     };
26.     void onDisconnect(BLEServer* pServer) {
27.       deviceConnected = false;
28.     }
29. };
31. void setup() {
32.   Serial.begin(115200);
33.   Wire.begin (); // join i2c bus with address 0x52
34.   nunchuck_init (); // send the initilization handshake
35.   BLEDevice::init(DEVICE_NAME);
36.   BLEServer *pServer = BLEDevice::createServer();
37.   pServer->setCallbacks(new MyServerCallbacks());
38.   BLEService *pService = pServer->createService(SERVICE_UUID);
39.   pCharacteristic = pService->createCharacteristic(
40.                       CHARACTERISTIC_UUID,
41.                       BLECharacteristic::PROPERTY_READ |
42.                       BLECharacteristic::PROPERTY_WRITE |
43.                       BLECharacteristic::PROPERTY_NOTIFY |
44.                       BLECharacteristic::PROPERTY_INDICATE
45.                     );
47.   pCharacteristic->addDescriptor(new BLE2902());
48.   pService->start();
49.   pServer->getAdvertising()->start();
50.   Serial.println("Waiting a client connection to notify...");
51. }
53. void nunchuck_init () {
54.   Wire.beginTransmission (0x52); // transmit to device 0x52
55.   Wire.write (0x40); // sends memory address *(blackNunchuck:0xF0）
56.   Wire.write (0x00); // sends sent a zero. *(blackNunchuck:0x55）
57.   Wire.endTransmission (); // stop transmitting
58. }
60. void send_zero () {
61.   Wire.beginTransmission (0x52); // transmit to device 0x52
62.   Wire.write (0x00); // sends one byte
63.   Wire.endTransmission (); // stop transmitting
64. }
66. void loop() {
67.   Wire.requestFrom (0x52, 6); // request data from nunchuck
68.   while (Wire.available ()) {
69.     nunbuff[cnt] = nunchuk_decode_byte (Wire.read ());
70.     cnt++;
71.   }
72.   int z = 0;
73.   int c = 0;
74.   if (cnt >= 5) {
75.     x_dat = nunbuff[0];
76.     y_dat = nunbuff[1];
77.     //x_dat=map(x_dat,49,205,0,255);
78.     //y_dat=map(y_dat,49,205,0,255);
79.     Serial.print("x_dat= ");
80.     Serial.print(x_dat);
81.     Serial.print(", y_dat= ");
82.     Serial.println(y_dat);
83.     if ((nunbuff[5] >> 0) & 1) z = 1; // The first bit of data of the 5byte (Nuncuck Z-button)
84.     if ((nunbuff[5] >> 1) & 1) c = 1; // The second bit of data of the 5byte (Nuncuck C-button)
85.     if ((z == 1) & (c == 1))z_dat = 0;
86.     if ((z == 0) & (c == 1))z_dat = 1;
87.     if ((z == 1) & (c == 0))z_dat = 2;
88.     if ((z == 0) & (c == 0))z_dat = 3;
89.     delay(1);
90.   }
91.   cnt = 0;
92.   send_zero (); // send the request for next bytes
93.   delay (10);
94.   if (deviceConnected) {
95.     char str1 = x_dat;
96.     char str2 = y_dat;
97.     char str3 = z_dat;
98.     char str4[10];
99.     sprintf(str4, "%d,%d,%d\n", str1, str2, str3);
100.     printf("%s", str4);
101.     pCharacteristic->setValue(str4);
102.     pCharacteristic->notify();
103.     delay (10);
104.   }
105. }
107. char nunchuk_decode_byte (char x) {
108.   x = (x ^ 0x17) + 0x17;
109.   return x;
110. }