diff --git a/include/sta/rtos/timer.hpp b/include/sta/rtos/timer.hpp
index 2d0cf3d..7507c3a 100644
--- a/include/sta/rtos/timer.hpp
+++ b/include/sta/rtos/timer.hpp
@@ -57,12 +57,13 @@ namespace sta
 		 */
 		void stop() override;
 
+		/**
+		 * @returns True of the timmer is currently running.
+		 */
+		bool isRunning();
+
 	private:
-		static void timeoutHandler(void* arg)
-		{
-			RtosTimer* timer = static_cast<RtosTimer*>(arg);
-			timer->callback_(timer->callbackArg_);
-		}
+		static void timeoutHandler(void* arg);
 
 	private:
 		osTimerId_t timer_id_;                  /**< CMSIS RTOS2 Timer */
@@ -70,6 +71,7 @@ namespace sta
 
         std::function<void(void*)> callback_;	/**< The callback to call on timeout. */
         void* callbackArg_;						/**< The argument to pass to the callback. */
+        bool running_;							/**< The current state of the timer. Running or not? */
 	};
 } // namespace sta
 
diff --git a/src/timer.cpp b/src/timer.cpp
index dbaab72..967396d 100644
--- a/src/timer.cpp
+++ b/src/timer.cpp
@@ -5,7 +5,11 @@
 
 namespace sta {
     RtosTimer::RtosTimer(void (*callback)(void *arg), void *arg)
-    	: timer_id_{NULL}, timer_attr_{.name="Timer", .attr_bits=osTimerOnce, .cb_size=sizeof(osTimerAttr_t)}, callback_{callback}, callbackArg_{arg}
+    	: timer_id_{NULL},
+		  timer_attr_{.name="Timer", .attr_bits=osTimerOnce, /*.cb_size=sizeof(osTimerAttr_t)*/},
+		  callback_{callback},
+		  callbackArg_{arg},
+		  running_{false}
     {
     	// Pass an anonymous function as the callback which will invoke the currently registered callback.
         timer_id_ = osTimerNew(timeoutHandler, osTimerOnce, arg, &timer_attr_);
@@ -19,6 +23,8 @@ namespace sta {
 
     RtosTimer::~RtosTimer()
     {
+    	if (isRunning()) stop();
+
         osTimerDelete(timer_id_);
     }
 
@@ -32,13 +38,38 @@ namespace sta {
     {
         osStatus_t status = osTimerStart(timer_id_, millis);
 
-        if (status != osOK) STA_DEBUG_PRINTLN("Timer start failed");
+        if (status != osOK)
+        {
+        	STA_DEBUG_PRINTLN("Timer start failed");
+        	return;
+        }
+
+        running_ = true;
     }
 
     void RtosTimer::stop()
     {
         osStatus_t status = osTimerStop(timer_id_);
         
-        if (status != osOK) STA_DEBUG_PRINTLN("Timer stop failed");
+        if (status != osOK)
+		{
+        	STA_DEBUG_PRINTLN("Timer stop failed");
+        	return;
+		}
+
+        running_ = false;
     }
+
+    bool RtosTimer::isRunning()
+    {
+    	return running_;
+    }
+
+    void RtosTimer::timeoutHandler(void* arg)
+    {
+		RtosTimer* timer = static_cast<RtosTimer*>(arg);
+		timer->running_ = false;
+		timer->callback_(timer->callbackArg_);
+	}
+
 } // namespace sta