diff --git a/Project/applications/smartcities/Makefile b/Project/applications/smartcities/Makefile
index 4b371da..3179a82 100644
--- a/Project/applications/smartcities/Makefile
+++ b/Project/applications/smartcities/Makefile
@@ -10,7 +10,7 @@
 SDK_ROOT = ../../
 PROJECT_OUT = smartcities
 
-USER_SRC = main.c httpClient.c
+USER_SRC = main.c httpClient.c callbacks.c
 USER_INCDIR = include/
 
 # if you need to add build Defines options add to USER_DEFS define 
diff --git a/Project/applications/smartcities/httpClient.c b/Project/applications/smartcities/httpClient.c
index 79cbccf..87efd2b 100644
--- a/Project/applications/smartcities/httpClient.c
+++ b/Project/applications/smartcities/httpClient.c
@@ -42,8 +42,8 @@ int httpRequest(struct httpHeaders head, char* content, int content_size)
 	int request_size = head_size + content_size + 2*(sizeof ENDL) + sizeof '\0';
 	/* WARNING
 	 *
-	 * 1. Te has olvidado el free de liberar memoria. Es SÚPER IMPORTANTE no dejar memoria sin liberar por que genera memory leaks y no vamos sobraos de ram
-	 * 2. Recuerda cambiarlo luego a chHeapAlloc y chHeapFree, yo suelo hacerme unos .c's aparte en mi carpeta para no mezclar código de prueba con código de la repo, pero mientras luego lo cambies cap problema
+	 * 1. Te has olvidado el free de liberar memoria. Es SÚPER IMPORTANTE no dejar memoria sin liberar por que genera memory leaks y no vamos sobraos de ram. Pa más infor sobre memory leaks, consulte al Manol más cercano.
+	 * 2. Recuerda cambiarlo luego a chHeapAlloc y chHeapFree, yo suelo hacerme unos .c's aparte en mi carpeta para no mezclar código de prueba con código de la repo, pero mientras luego lo cambies cap problema.
 	 * 
 	 * --Imanol
 	 */
diff --git a/Project/applications/smartcities/include/module.h b/Project/applications/smartcities/include/module.h
index 0323b3d..e0a2659 100644
--- a/Project/applications/smartcities/include/module.h
+++ b/Project/applications/smartcities/include/module.h
@@ -1,6 +1,6 @@
 #ifndef MODULE_H
 #define MODULE_H
 
-#define SERIAL_NUMBER	123456
+#define SERIAL_NUMBER	"123456"
 
 #endif
\ No newline at end of file
diff --git a/Project/applications/smartcities/json.c b/Project/applications/smartcities/json.c
index 2f67f87..2564b95 100644
--- a/Project/applications/smartcities/json.c
+++ b/Project/applications/smartcities/json.c
@@ -21,8 +21,26 @@ char* prepare_json_observation_statement(char** data, uint32_t nObservations)
 
 char* prepare_json_register_statement(char* module_ID, uint8_t sensor_type)
 {
+	//id, desc, type, unit
+
+	unsigned int i, length, observation_length;
+	char *json_statement, *str_aux, *str_aux2;
+	length = 17;
+	str_aux = join_strings("{\"observations\":[","",length,0,JOIN_NO_FREE);
+	for(i = 0; i < nObservations; i++)
+	{
+		str_aux2 = prepare_observation(data[i],strlen(data[i]));
+		observation_length = strlen(str_aux2);
+		str_aux = join_strings(str_aux,str_aux2,length,observation_length,JOIN_FREE_MEM);
+		length += observation_length;
+	}
+	length--; //REMOVE LAST ','
+	json_statement = join_strings(str_aux,"]}",length,2,JOIN_NO_FREE);
+	chHeapFree(str_aux);
+	return json_statement;
+
 	char *json_data, *str_aux, *str_aux2;
-	int value_length = find_next_index(observation,length,','); //EXPECTS FORMATTING!!!
+	int value_length = find_next_index(observation,length,',');
 	int timestamp_length = length - (value_length + 1);
 	char *value = (char*) chHeapAlloc(NULL,value_length+1);
 	char *timestamp = (char*) chHeapAlloc(NULL,timestamp_length+1);
@@ -43,6 +61,13 @@ char* prepare_json_register_statement(char* module_ID, uint8_t sensor_type)
 char* prepare_observation(char* observation, uint32_t length)
 {
 	char *json_data, *str_aux, *str_aux2;
+	/* TOPKEK
+	 *
+	 * ¿Gestión de errores?
+	 * ¿PA QUÉ?
+	 *
+	 * --le trole
+	 */
 	int value_length = find_next_index(observation,length,','); //EXPECTS FORMATTING!!!
 	int timestamp_length = length - (value_length + 1);
 	char *value = (char*) chHeapAlloc(NULL,value_length+1);
@@ -88,6 +113,14 @@ uint8_t send_observation(char* statement, uint32_t length, char* provider_ID, ch
 		strcpy(URL+16+SERVER_HOSTNAME_LENGTH+strlen(provider_ID),"/");
 		strcpy(URL+17+SERVER_HOSTNAME_LENGTH+strlen(provider_ID),sensor_ID);
 	}
+
+	/* SELF-REMINDER
+	 *
+	 * Cambiar esto pa usar la función de Ferràn
+	 *
+	 * --Imanol
+	 */
+
 	response_code = http_post(URL,statement,URL_length,length);
 	if(response code == 200)
 	{
@@ -128,6 +161,4 @@ char* join_strings(char* str1, char* str2, uint32_t len1, uint32_t len2, uint8_t
 		free(str2);
 	}
 	return str; 
-}
-
-//id, desc, type, unit
\ No newline at end of file
+}
\ No newline at end of file
diff --git a/Project/applications/smartcities/main.c b/Project/applications/smartcities/main.c
index 53c6800..61a4c3c 100644
--- a/Project/applications/smartcities/main.c
+++ b/Project/applications/smartcities/main.c
@@ -3,6 +3,7 @@
 #include "lwip/inet.h"
 #include "globals.h"
 #include "httpClient.h"
+#include "callbacks.h"
 
 #define WIFI_MODE				WIFI_MODE_CLIENT
 #define NETWORK_SSID			"linksys"
@@ -16,29 +17,12 @@ void initLibwismart(void)
 	libwismart_Init(hwif);
 }
 
-void dhcp_connect_result_cb(int result)
-{
-	libwismart_ip_addr_t ip;
-	if(result==LIBWISMART_DHCP_ADDRESS_ASSIGNED)
-	{
-		libwismart_GetCurrentIP(&ip,NULL,NULL);
-		printf("IP: %d.%d.%d.%d \r\n",ip.addr[3],ip.addr[2],ip.addr[1],ip.addr[0]);
-	}
-	else if(result==LIBWISMART_DHCP_TIMEOUT)
-	{
-		printf("DHCP timeout\r\n");
-	}
-	else
-	{
-		printf("DHCP error\r\n");
-	}
-	
-}
-
-void wifi_connect_result_cb(int result)
-{
-    printf("WiFi Connect indication: %s\r\n", (result == WISMART_WIFI_CONNECTED) ? "Connected": "Failed\r\n");
-}
+/* erase me
+ * 
+ * He movido los callbacks a un .c y .h aparte para mayor modularidad, conveniéntemente llamados callbacks.c y callbacks.h
+ *
+ * --Imanol
+ */
 
 int main(void)
 {