GPS data upload and visualization using LinkIt ONE and IoT Hub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
#include <PubSubClient.h>

#include <LWiFi.h>
#include <LWiFiClient.h>
#include <LGPS.h>
#include <LBattery.h>

#define WIFI_AP "YOUR_WIFI_AP"
#define WIFI_PASSWORD "YOUR_WIFI_PASSWORD"
#define WIFI_AUTH LWIFI_WPA  // choose from LWIFI_OPEN, LWIFI_WPA, or LWIFI_WEP.

#define TOKEN "YOUR_ACCESS_TOKEN"

gpsSentenceInfoStruct gpsInfo;

char thingsboardServer[] = "device.iothub.magenta.at";

LWiFiClient wifiClient;

PubSubClient client( wifiClient );

unsigned long lastSend;

void setup()
{
  Serial.begin(115200);
  LGPS.powerOn();
  Serial.println("GPS started.");
  InitLWiFi();
  client.setServer( thingsboardServer, 1883 );
  lastSend = 0;
}

void loop()
{
  LWifiStatus ws = LWiFi.status();
  boolean status = wifi_status(ws);
  if (!status) {
    Serial.println("Connecting to AP ...");
    while (0 == LWiFi.connect(WIFI_AP, LWiFiLoginInfo(WIFI_AUTH, WIFI_PASSWORD)))
    {
      delay(500);
    }
    Serial.println("Connected to AP");
  }

  if ( !client.connected() ) {
    reconnect();
  }

  if ( millis() - lastSend > 1000 ) { // Update and send only after 1 seconds
    getAndSendGPSData();
    lastSend = millis();
  }

  client.loop();

}

void getAndSendGPSData()
{
  Serial.println("Collecting GPS data.");
  LGPS.getData(&gpsInfo);
  Serial.println((char*)gpsInfo.GPGGA);

  char latitude[20];
  char lat_direction[1];
  char longitude[20];
  char lon_direction[1];
  char buf[20];
  char time[30];

  const char* p = (char*)gpsInfo.GPGGA;

  p = nextToken(p, 0); // GGA
  p = nextToken(p, time); // Time
  p = nextToken(p, latitude); // Latitude
  p = nextToken(p, lat_direction); // N or S?
  p = nextToken(p, longitude); // Longitude
  p = nextToken(p, lon_direction); // E or W?
  p = nextToken(p, buf); // fix quality

  const int coord_size = 8;
  char lat_fixed[coord_size], lon_fixed[coord_size];
  convertCoords(latitude, longitude, lat_direction, lon_direction, lat_fixed, lon_fixed, coord_size);

  Serial.print("Latitude:");
  Serial.println(lat_fixed);

  Serial.print("Longitude:");
  Serial.println(lon_fixed);

  if (buf[0] == '1')
  {
    // GPS fix
    p = nextToken(p, buf); // number of satellites
    Serial.print("GPS is fixed:");
    Serial.print(atoi(buf));
    Serial.println(" satellite(s) found!");
  }
  else
  {
    Serial.println("GPS is not fixed yet.");
  }

  // Obtain battery level
  String batteryLevel = String(LBattery.level());
  String batteryCharging = LBattery.isCharging() == 1 ? "true" : "false";

  // Just debug messages
  Serial.print( "Sending gps location and battery level: [" );
  Serial.print( lat_fixed ); Serial.print( lon_fixed );
  Serial.print(" Battery level: "); Serial.print( batteryLevel );
  Serial.print(" Battery charging: "); Serial.print( batteryCharging );
  Serial.print( "]   -> " );

  // Prepare a JSON payload string
  String payload = "{";
  payload += "\"latitude\":"; payload += lat_fixed; payload += ", ";
  payload += "\"longitude\":"; payload += lon_fixed; payload += ", ";
  payload += "\"batteryLevel\":"; payload += batteryLevel;  payload += ", ";
  payload += "\"batteryCharging\":"; payload += batteryCharging;
  payload += "}";

  // Send payload
  char attributes[100];
  payload.toCharArray( attributes, 100 );
  client.publish( "v1/devices/me/attributes", attributes );
  Serial.println( attributes );
}

void InitLWiFi()
{
  LWiFi.begin();
  // Keep retrying until connected to AP
  Serial.println("Connecting to AP ...");
  while (0 == LWiFi.connect(WIFI_AP, LWiFiLoginInfo(WIFI_AUTH, WIFI_PASSWORD))) {
    delay(500);
  }
  Serial.println("Connected to AP");
}

void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    Serial.print("Connecting toIoT Hub node ...");
    // Attempt to connect (clientId, username, password)
    if ( client.connect("LinkIt One Device", TOKEN, NULL) ) {
      Serial.println( "[DONE]" );
    } else {
      Serial.print( "[FAILED] [ rc = " );
      Serial.print( client.state() );
      Serial.println( " : retrying in 5 seconds]" );
      // Wait 5 seconds before retrying
      delay( 5000 );
    }
  }
}

void convertCoords(const char* latitude, const char* longitude, const char* lat_direction,
                   const char* lon_direction, char* lat_return, char* lon_return, int buff_length)
{
  char lat_deg[3];

  // extract the first 2 chars to get the latitudinal degrees
  strncpy(lat_deg, latitude, 2);

  // null terminate
  lat_deg[2] = 0;

  char lon_deg[4];

  // extract first 3 chars to get the longitudinal degrees
  strncpy(lon_deg, longitude, 3);

  // null terminate
  lon_deg[3] = 0;

  // convert to integer from char array
  int lat_deg_int = arrayToInt(lat_deg);
  int lon_deg_int = arrayToInt(lon_deg);

  // must now take remainder/60
  // this is to convert from degrees-mins-secs to decimal degrees
  // so the coordinates are "google mappable"

  // convert the entire degrees-mins-secs coordinates into a float - this is for easier manipulation later
  float latitude_float = arrayToFloat(latitude);
  float longitude_float = arrayToFloat(longitude);

  // remove the degrees part of the coordinates - so we are left with only minutes-seconds part of the coordinates
  latitude_float = latitude_float - (lat_deg_int * 100);
  longitude_float = longitude_float - (lon_deg_int * 100);

  // convert minutes-seconds to decimal
  latitude_float /= 60;
  longitude_float /= 60;

  // add back on the degrees part, so it is decimal degrees
  latitude_float += lat_deg_int;
  longitude_float += lon_deg_int;

  if (strcmp (lat_direction, "S") == 0) {
    latitude_float *= -1;
  }

  if (strcmp (lon_direction, "W") == 0) {
    longitude_float *= -1;
  }

  // format the coordinates nicey - no more than 6 decimal places
  snprintf(lat_return, buff_length, "%2.6f", latitude_float);
  snprintf(lon_return, buff_length, "%3.6f", longitude_float);
}

int arrayToInt(const char* char_array)
{
  int temp;
  sscanf(char_array, "%d", &temp);
  return temp;
}

float arrayToFloat(const char* char_array)
{
  float temp;
  sscanf(char_array, "%f", &temp);
  return temp;
}

const char *nextToken(const char* src, char* buf)
{
  int i = 0;
  while (src[i] != 0 && src[i] != ',')
    i++;
  if (buf)
  {
    strncpy(buf, src, i);
    buf[i] = 0;
  }
  if (src[i])
    i++;
  return src + i;
}

boolean wifi_status(LWifiStatus ws) {
  switch (ws) {
    case LWIFI_STATUS_DISABLED:
      return false;
      break;
    case LWIFI_STATUS_DISCONNECTED:
      return false;
      break;
    case LWIFI_STATUS_CONNECTED:
      return true;
      break;
  }
  return false;
}