Add available() API

Author: sandeepmistry

examples/GsmLocation/GsmLocation.ino

@@ -2,7 +2,7 @@
   Location
 
   This sketch uses the celluar network to determine the location of a MKR GSM 1400 board
-  and prints it to the Serial monitor. The location is  based on the cellular towers in 
+  and prints it to the Serial monitor. The location is  based on the cellular towers in
   range, and requires a GPRS data connection to be enabled.
 
   Circuit:
@@ -31,11 +31,6 @@ GSMLocation location;
 GPRS gprs;
 GSM gsmAccess;
 
-float latitude;
-float longitude;
-long altitude;
-long accuracy;
-
 void setup() {
   // initialize serial communications and wait for port to open:
   Serial.begin(9600);
@@ -63,27 +58,21 @@ void setup() {
 }
 
 void loop() {
-  // update the location variables
-  latitude = location.latitude();
-  longitude = location.longitude();
-  altitude = location.altitude();
-  accuracy = location.accuracy();
-
-  Serial.print("Location: ");
-  Serial.print(latitude, 7);
-  Serial.print(", ");
-  Serial.println(longitude, 7);
+  if (location.available()) {
+    Serial.print("Location: ");
+    Serial.print(location.latitude(), 7);
+    Serial.print(", ");
+    Serial.println(location.longitude(), 7);
 
-  Serial.print("Altitude: ");
-  Serial.print(altitude);
-  Serial.println("m");
+    Serial.print("Altitude: ");
+    Serial.print(location.altitude());
+    Serial.println("m");
 
-  Serial.print("Accuracy: +/- ");
-  Serial.print(accuracy);
-  Serial.println("m");
+    Serial.print("Accuracy: +/- ");
+    Serial.print(location.accuracy());
+    Serial.println("m");
 
-  Serial.println();
-
-  delay(1000);
+    Serial.println();
+  }
 }
 

src/GSMLocation.cpp

@@ -22,8 +22,8 @@
 #define GSM_LOCATION_UPDATE_INTERVAL 1100
 
 GSMLocation::GSMLocation() :
-  _locationUpdated(false),
-  _lastRequestTime(0),
+  _commandSent(false),
+  _locationAvailable(false),
   _latitude(0),
   _longitude(0),
   _altitude(0),
@@ -45,40 +45,48 @@ int GSMLocation::begin()
     return 0;
   }
 
-  updateIfNeeded();
+  return 1;
+}
+
+int GSMLocation::available()
+{
+  MODEM.poll();
+
+  if (!_commandSent) {
+    _commandSent = true;
+    _locationAvailable = false;
 
-  for (unsigned long start = millis(); !_locationUpdated && millis() < (start + 10000); ) {
-    MODEM.poll();
+    MODEM.send("AT+ULOC=2,2,0,1,1");
+    MODEM.waitForResponse();
   }
 
-  return 1;
+  if (_locationAvailable) {
+    _commandSent = false;
+    _locationAvailable = false;
+
+    return 1;
+  }
+
+  return 0;
 }
 
 float GSMLocation::latitude()
 {
-  updateIfNeeded();
-
   return _latitude;
 }
 
 float GSMLocation::longitude()
 {
-  updateIfNeeded();
-
   return _longitude;
 }
 
 long GSMLocation::altitude()
 {
-  updateIfNeeded();
-
   return _altitude;
 }
 
 long GSMLocation::accuracy()
 {
-  updateIfNeeded();
-
   return _uncertainty;
 }
 
@@ -88,7 +96,7 @@ void GSMLocation::handleUrc(const String& urc)
     String temp = urc;
     int lastCommaIndex;
 
-    _locationUpdated = true;
+    _locationAvailable = true;
 
     lastCommaIndex = temp.lastIndexOf(',');
     _uncertainty = temp.substring(lastCommaIndex + 1).toInt();
@@ -107,19 +115,3 @@ void GSMLocation::handleUrc(const String& urc)
     temp.remove(lastCommaIndex);
   }
 }
-
-void GSMLocation::updateIfNeeded()
-{
-  MODEM.poll();
-
-  if ((millis() - _lastRequestTime) < GSM_LOCATION_UPDATE_INTERVAL) {
-    return;
-  }
-
-  _lastRequestTime = millis();
-  MODEM.send("AT+ULOC=2,2,0,1,1");
-
-  if (MODEM.waitForResponse() != 1) {
-    return;
-  }
-}

src/GSMLocation.h

@@ -32,6 +32,8 @@ class GSMLocation : public ModemUrcHandler {
 
   int begin();
 
+  int available();
+
   float latitude();
   float longitude();
   long altitude();
@@ -40,11 +42,8 @@ class GSMLocation : public ModemUrcHandler {
   void handleUrc(const String& urc);
 
 private:
-  void updateIfNeeded();
-
-private:
-  bool _locationUpdated;
-  unsigned long _lastRequestTime;
+  bool _commandSent;
+  bool _locationAvailable;
 
   float _latitude;
   float _longitude;