diff --git a/Valve.cpp b/Valve.cpp
index b0700bf..198e6f0 100644
--- a/Valve.cpp
+++ b/Valve.cpp
@@ -19,7 +19,7 @@ Valve::Valve(uint gpio_motor1, uint gpio_motor2, uint gpio_start, uint gpio_end)
 
 
 void Valve::open() {
-	if (state == State::Opening) {
+	if (state == State::Opening || pending_state == State::Opening) {
 		return;
 	}
 	gpio_put(motor2, 0);
@@ -30,7 +30,7 @@ void Valve::open() {
 
 
 void Valve::close() {
-	if (state == State::Closing) {
+	if (state == State::Closing || pending_state == State::Closing) {
 		return;
 	}
 	gpio_put(motor1, 0);
@@ -52,7 +52,7 @@ Valve::State Valve::process() {
 		if (duration_cast<seconds>(steady_clock::now() - start_time) > timeout) {
 			gpio_put(motor1, 0);
 			gpio_put(motor2, 0);
-			state = State::Unknown;
+			state = pending_state = State::Unknown;
 		}
 	}
 	return state;
diff --git a/Valve.h b/Valve.h
index f4be57d..7051481 100644
--- a/Valve.h
+++ b/Valve.h
@@ -24,7 +24,12 @@ public:
 private:
 	uint motor1, motor2;
 	uint start_pin, end_pin;
-	State state                  = State::Unknown;
-	std::chrono::seconds timeout = std::chrono::seconds(10);
+
+	std::chrono::seconds timeout         = std::chrono::seconds(10);
+	std::chrono::milliseconds transition = std::chrono::milliseconds(1000);
 	decltype(std::chrono::steady_clock::now()) start_time;
+	decltype(std::chrono::steady_clock::now()) transition_time;
+
+	State state         = State::Unknown;
+	State pending_state = State::Unknown;
 };
diff --git a/ValveController.cpp b/ValveController.cpp
index 706469b..68186e6 100644
--- a/ValveController.cpp
+++ b/ValveController.cpp
@@ -3,6 +3,20 @@
 
 #include <pico/stdlib.h>
 
+enum class LedState {
+	Off,
+	On,
+	Blink
+};
+
+LedState led_state = LedState::Off;
+
+bool led_timer_callback(struct repeating_timer * t) {
+	if (led_state == LedState::Blink) {
+		gpio_put(PICO_DEFAULT_LED_PIN, !gpio_get(PICO_DEFAULT_LED_PIN));
+	}
+	return true;
+}
 
 int main() {
 	Valve cold_valve{10, 11, 12, 13};
@@ -14,6 +28,9 @@ int main() {
 	gpio_init_input(button_open);
 	gpio_init_input(button_close);
 
+	struct repeating_timer led_timer;
+	add_repeating_timer_ms(-200, led_timer_callback, NULL, &led_timer);
+
 	const int tick_ms = 50;
 	while (true) {
 		if (gpio_get(button_open) == 0) {
@@ -28,14 +45,16 @@ int main() {
 		const auto cst = cold_valve.process();
 		hot_valve.process();
 		switch (cst) {
-		case Valve::State::Opened:
-		case Valve::State::Closed: gpio_put(PICO_DEFAULT_LED_PIN, 1); break;
-		default: break;
+		case Valve::State::Opened: led_state = LedState::On; break;
+		case Valve::State::Closed: led_state = LedState::Off; break;
+		case Valve::State::Opening: led_state = LedState::Blink; break;
+		case Valve::State::Closing: led_state = LedState::Blink; break;
+		case Valve::State::Unknown: led_state = LedState::Off; break;
 		}
-		if (cst == Valve::State::Opened || cst == Valve::State::Closed) {
-			gpio_put(PICO_DEFAULT_LED_PIN, 1);
-		} else {
-			gpio_put(PICO_DEFAULT_LED_PIN, 0);
+		switch (led_state) {
+		case LedState::On: gpio_put(PICO_DEFAULT_LED_PIN, 1); break;
+		case LedState::Off: gpio_put(PICO_DEFAULT_LED_PIN, 0); break;
+		default: break;
 		}
 	}
 	return 0;
diff --git a/gpio_common.c b/gpio_common.c
index 82a4cb3..ebf8fd2 100644
--- a/gpio_common.c
+++ b/gpio_common.c
@@ -2,10 +2,6 @@
 
 #include <pico/stdlib.h>
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
 
 void gpio_init_out(uint gpio) {
 	gpio_set_dir(gpio, GPIO_OUT);
@@ -19,8 +15,3 @@ void gpio_init_input(uint gpio) {
 	gpio_pull_up(gpio);
 	gpio_set_function(gpio, GPIO_FUNC_SIO);
 }
-
-
-#ifdef __cplusplus
-}
-#endif