diff --git a/include/sync_service.h b/include/sync_service.h
index 7a9fad6..d1c25c7 100644
--- a/include/sync_service.h
+++ b/include/sync_service.h
@@ -8,6 +8,6 @@
 #define SYNC_SERVICE_H
 
 int sync_service_init(void);
-int sync_service_run(void);
+uint32_t sync_service_run(void);
 
 #endif
diff --git a/include/tracing.h b/include/tracing.h
index 91a908b..1ef9005 100644
--- a/include/tracing.h
+++ b/include/tracing.h
@@ -8,6 +8,6 @@
 #define TRACING_H
 
 int tracing_init(void);
-int tracing_run(void);
+uint32_t tracing_run(void);
 
 #endif
\ No newline at end of file
diff --git a/src/main.c b/src/main.c
index 23ec9e1..4d75344 100644
--- a/src/main.c
+++ b/src/main.c
@@ -65,7 +65,11 @@ void main(void) {
     printk("Components initialized! Starting Tracing and Gatt...\n");
 
     do {
-        tracing_run();
-        sync_service_run();
+        uint32_t tracing_sleep_ms = tracing_run();
+        uint32_t sync_sleep_ms = sync_service_run();
+
+        uint32_t sleep_ms = MIN(tracing_sleep_ms, sync_sleep_ms);
+        //printk("Sleeping a bit (%u ms)...\n", sleep_ms);
+        k_sleep(K_MSEC(sleep_ms)); // TODO: what to put here?
     } while (1);
 }
\ No newline at end of file
diff --git a/src/sync_service.c b/src/sync_service.c
index a6ae4c1..2fb24df 100644
--- a/src/sync_service.c
+++ b/src/sync_service.c
@@ -12,16 +12,35 @@
 #include <sys/byteorder.h>
 #include <zephyr.h>
 
-#include <bluetooth/bluetooth.h>
-#include <bluetooth/conn.h>
-#include <bluetooth/uuid.h>
-#include <bluetooth/gatt.h>
+#define SYNC_ADV_INTERVAL_MS (60*1000)
+#define SYNC_ADV_DURATION_MS 500
+#define SYNC_CONN_INIT_WAIT_MS 250
 
+K_TIMER_DEFINE(sync_adv_timer, NULL, NULL);
 
 int sync_service_init(void) {
-    return 0; // TODO!
+    // We init the timers (which should run periodically!)
+    // we directly want to advertise ourselfs after the start -> should reduce unwanted delays
+    k_timer_start(&sync_adv_timer, K_NO_WAIT, K_MSEC(SYNC_ADV_INTERVAL_MS));
+    return 0;
 }
 
-int sync_service_run(void) {
-    return 0;
+void sync_service_handle_connection() {
+
+    // TODO: Implement me!
+}
+
+uint32_t sync_service_run(void) {
+
+    if (k_timer_status_get(&sync_adv_timer) > 0) {
+
+         // TODO: START ADVERTISEMENTS
+         //printk("Advertising Sync service...!\n");
+         k_sleep(K_MSEC(SYNC_ADV_DURATION_MS));
+         // TODO: STOP ADVERTISEMENTS
+    }
+     // TODO: CHECK IF A CONNECTION HAPPENED UNTIL NOW if so -> handle it!
+
+    // we return the timer time so that main can sleep
+    return k_timer_remaining_get(&sync_adv_timer);
 }
\ No newline at end of file
diff --git a/src/tracing.c b/src/tracing.c
index 5f9701c..66daa28 100644
--- a/src/tracing.c
+++ b/src/tracing.c
@@ -26,10 +26,9 @@
 typedef ENIntervalIdentifier ENIntervalIdentifier;
 
 #define RPI_ROTATION_MS (11*60*1000)
-#define SCAN_INTERVAL_MS (10*1000)
+#define SCAN_INTERVAL_MS (60*1000)
 #define SCAN_DURATION_MS 1000
 #define ADV_INTERVAL_MS 220
-#define ADV_DURATION_MS 1000
 
 
 K_TIMER_DEFINE(rpi_timer, NULL, NULL);
@@ -49,14 +48,10 @@ int tracing_init()
     k_timer_start(&adv_timer, K_MSEC(ADV_INTERVAL_MS), K_MSEC(ADV_INTERVAL_MS));
 
 
-
-
-
-
     return 0;
 }
 
-int tracing_run()
+uint32_t tracing_run()
 {
     if (k_timer_status_get(&rpi_timer) > 0) {
         on_rpi();
@@ -70,13 +65,10 @@ int tracing_run()
         on_adv();
     }
 
-    k_sleep(K_MSEC(ADV_INTERVAL_MS)); // TODO: what to put here?
-
-    //printk("covid start\n");
-
-
-    //printk("covid end\n");
-    return 0;
+    // we return the minimum timer time so that main can sleep
+    return MIN( k_timer_remaining_get(&rpi_timer),
+                MIN(k_timer_remaining_get(&scan_timer),
+                    k_timer_remaining_get(&adv_timer)));
 }