diff --git a/src/globals.h b/src/globals.h
index cb7b720f..04ef15d7 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -51,8 +51,8 @@ typedef struct {
 
 #ifdef HAS_GPS
   typedef struct {
-    float latitude;
-    float longitude;
+    uint32_t latitude;
+    uint32_t longitude;
     uint8_t satellites;
     uint16_t hdop;
     uint16_t altitude;
diff --git a/src/gpsread.cpp b/src/gpsread.cpp
index 99c3b02e..4747f7a6 100644
--- a/src/gpsread.cpp
+++ b/src/gpsread.cpp
@@ -7,8 +7,8 @@ static const char TAG[] = "main";
 
 // read GPS data and cast to global struct
 void gps_read(){
-    gps_status.latitude     =   (float) gps.location.lat();
-    gps_status.longitude    =   (float) gps.location.lng();
+    gps_status.latitude     =   (uint32_t) gps.location.lat() * 100;
+    gps_status.longitude    =   (uint32_t) gps.location.lng() * 100;
     gps_status.satellites   =   (uint8_t) gps.satellites.value();
     gps_status.hdop         =   (uint16_t) gps.hdop.value();
     gps_status.altitude     =   (uint16_t) gps.altitude.meters(); 
@@ -25,18 +25,29 @@ void gps_loop(void * pvParameters) {
 
         if (cfg.gpsmode)
         {
-            // if GPS function is enabled try serial connect to GPS device
-            GPS_Serial.begin(HAS_GPS);
-            
-            while(cfg.gpsmode) {
-                // feed GPS decoder with serial NMEA data from GPS device
-                while (GPS_Serial.available()) {
-                    gps.encode(GPS_Serial.read());
-                    vTaskDelay(1/portTICK_PERIOD_MS); // reset watchdog
-                }
-            }    
-            // after GPS function was disabled, close connect to GPS device
-            GPS_Serial.end();
+            #ifdef GPS_SERIAL
+                // serial connect to GPS device
+                GPS_Serial.begin(GPS_SERIAL);
+                
+                while(cfg.gpsmode) {
+                    // feed GPS decoder with serial NMEA data from GPS device
+                    while (GPS_Serial.available()) {
+                        gps.encode(GPS_Serial.read());
+                        vTaskDelay(1/portTICK_PERIOD_MS); // reset watchdog
+                    }
+                }    
+                // after GPS function was disabled, close connect to GPS device
+                GPS_Serial.end();
+            #endif
+
+            #ifdef GPS_I2C
+                // I2C connect to GPS device
+                
+                /*
+                to be done
+                */
+
+            #endif
         }
        
         vTaskDelay(1/portTICK_PERIOD_MS); // reset watchdog
diff --git a/src/hal/lopy.h b/src/hal/lopy.h
index 137c8e53..dd5a0b7b 100644
--- a/src/hal/lopy.h
+++ b/src/hal/lopy.h
@@ -4,6 +4,11 @@
 #define HAS_LED NOT_A_PIN // LoPy4 has no on board LED, so we use RGB LED on LoPy4
 #define HAS_RGB_LED GPIO_NUM_0  // WS2812B RGB LED on GPIO0
 
+// use only if your LoPy lives on a Pytrack expansion board
+//#define HAS_GPS 1
+//#define GPS_I2C GPIO_NUM_9, GPIO_NUM_8 // SDA, SCL
+//#define HAS_BUTTON GPIO_NUM_4
+
 // Hardware pin definitions for Pycom LoPy board
 #define PIN_SPI_SS    GPIO_NUM_17
 #define PIN_SPI_MOSI  GPIO_NUM_27
diff --git a/src/hal/lopy4.h b/src/hal/lopy4.h
index 586f1bb2..721b11ef 100644
--- a/src/hal/lopy4.h
+++ b/src/hal/lopy4.h
@@ -4,6 +4,11 @@
 #define HAS_LED NOT_A_PIN // LoPy4 has no on board LED, so we use RGB LED on LoPy4
 #define HAS_RGB_LED   GPIO_NUM_0  // WS2812B RGB LED on GPIO0
 
+// use only if your LoPy lives on a Pytrack expansion board
+//#define HAS_GPS 1
+//#define GPS_I2C GPIO_NUM_9, GPIO_NUM_8 // SDA, SCL
+//#define HAS_BUTTON GPIO_NUM_4
+
 // Hardware pin definitions for Pycom LoPy4 board
 #define PIN_SPI_SS    GPIO_NUM_18
 #define PIN_SPI_MOSI  GPIO_NUM_27
diff --git a/src/hal/ttgobeam.h b/src/hal/ttgobeam.h
index fb5dae8b..aafbb3a9 100644
--- a/src/hal/ttgobeam.h
+++ b/src/hal/ttgobeam.h
@@ -6,7 +6,8 @@
 //#define HAS_BUTTON GPIO_NUM_39 // on board button "BOOT" (next to reset button) !! seems not to work!!
 #define HAS_BATTERY_PROBE ADC1_GPIO35_CHANNEL // battery probe GPIO pin -> ADC1_CHANNEL_7
 #define BATT_FACTOR 2 // voltage divider 100k/100k on board
-#define HAS_GPS 9600, SERIAL_8N1, GPIO_NUM_12, GPIO_NUM_15 // UBlox NEO 6M or 7M 
+#define HAS_GPS 1 // use on board GPS
+#define GPS_SERIAL 9600, SERIAL_8N1, GPIO_NUM_12, GPIO_NUM_15 // UBlox NEO 6M or 7M with default configuration
 
 // re-define pin definitions of pins_arduino.h
 #define PIN_SPI_SS    GPIO_NUM_18 // ESP32 GPIO18 (Pin18) -- HPD13A NSS/SEL (Pin4) SPI Chip Select Input