diff --git a/main.c b/main.c
index 94c7445..1ed013a 100644
--- a/main.c
+++ b/main.c
@@ -15,7 +15,7 @@
 /** CuVoodoo clapperboard firmware (for STM32F103Cx micro-controller)
  *  @file main.c
  *  @author King Kévin <kingkevin@cuvoodoo.info>
- *  @date 2016-2017
+ *  @date 2016-2018
  */
 
 /* standard libraries */
@@ -593,7 +593,12 @@ void main(void)
 	timer_enable_oc_output(TIM(BUZZER_TIMER), TIM_OC1); // enable output to generate PWM
 	timer_enable_oc_output(TIM(BUZZER_TIMER), TIM_OC1N); // enable output to generate PWM (complementary to be louder)
 	timer_enable_break_main_output(TIM(BUZZER_TIMER)); // enable master output
-	timer_generate_event(TIM(BUZZER_TIMER), TIM_EGR_UG); // generate update event to reload registers and reset counter 
+	timer_generate_event(TIM(BUZZER_TIMER), TIM_EGR_UG); // generate update event to reload registers and reset counter
+	// switch buzzer off by removing the output from the PWM
+	gpio_clear(GPIO(BUZZER_1_PORT), GPIO(BUZZER_1_PIN));
+	gpio_set_mode(GPIO(BUZZER_1_PORT), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(BUZZER_1_PIN));
+	gpio_clear(GPIO(BUZZER_2_PORT), GPIO(BUZZER_2_PIN));
+	gpio_set_mode(GPIO(BUZZER_2_PORT), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(BUZZER_2_PIN));
 	printf("OK\n");
 
 	// setup GPIO for reading buttons
@@ -628,12 +633,14 @@ void main(void)
 			action = true; // action has been performed
 			led_toggle(); // toggle LED to show activity
 			c = usart_getchar(); // store receive character
+			standby_timer = 0; // restart standby timer
 			char_flag = true; // notify character has been received
 		}
 		while (cdcacm_received) { // data received over USB
 			action = true; // action has been performed
 			led_toggle(); // toggle LED to show activity
 			c = cdcacm_getchar(); // store receive character
+			standby_timer = 0; // restart standby timer
 			char_flag = true; // notify character has been received
 		}
 		while (char_flag) { // user data received
@@ -684,7 +691,15 @@ void main(void)
 					if (morse[morse_i]) { // skip empty codes
 						if (morse_i%2) { // switch buzzer on for odd code
 							timer_disable_counter(TIM(BUZZER_TIMER)); // stop buzzing
+							// switch buzzer off by removing the output from the PWM
+							gpio_clear(GPIO(BUZZER_1_PORT), GPIO(BUZZER_1_PIN));
+							gpio_set_mode(GPIO(BUZZER_1_PORT), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(BUZZER_1_PIN));
+							gpio_clear(GPIO(BUZZER_2_PORT), GPIO(BUZZER_2_PIN));
+							gpio_set_mode(GPIO(BUZZER_2_PORT), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(BUZZER_2_PIN));
 						} else {
+							// allow PWM to control the output
+							gpio_set_mode(GPIO(BUZZER_1_PORT), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO(BUZZER_1_PIN));
+							gpio_set_mode(GPIO(BUZZER_2_PORT), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO(BUZZER_2_PIN));
 							timer_enable_counter(TIM(BUZZER_TIMER)); // start buzzing
 						}
 						morse[morse_i]--; // decrement remaining buzzing time
@@ -695,8 +710,11 @@ void main(void)
 				}
 				if (morse_i>=LENGTH(morse)) { // all codes done
 					morse_delay = -2; // Morse completed
-					gpio_clear(GPIO(BUZZER_1_PORT), GPIO(BUZZER_1_PIN)); // ensure it's not beeping
-					gpio_clear(GPIO(BUZZER_2_PORT), GPIO(BUZZER_2_PIN)); // ensure it's not beeping
+					// switch buzzer off by removing the output from the PWM
+					gpio_clear(GPIO(BUZZER_1_PORT), GPIO(BUZZER_1_PIN));
+					gpio_set_mode(GPIO(BUZZER_1_PORT), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(BUZZER_1_PIN));
+					gpio_clear(GPIO(BUZZER_2_PORT), GPIO(BUZZER_2_PIN));
+					gpio_set_mode(GPIO(BUZZER_2_PORT), GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(BUZZER_2_PIN));
 				}
 			}
 
@@ -741,7 +759,7 @@ void main(void)
 			uint16_t buttons_diff = buttons^buttons_new; // get difference
 			buttons = buttons_new; // save new state
 			if (buttons_diff) { // only do something if there is a change
-				//printf("button pressed: %016b\n", buttons);
+				printf("button pressed: %016b\n", buttons);
 				for (uint8_t number=0; number<LENGTH(numbers); number++) { // check buttons for every number
 					if (buttons_diff&(1<<numbers[number].up) || buttons_diff&(1<<numbers[number].down)) { // a button for the number has been pressed
 						if (buttons&(1<<numbers[number].up) && buttons&(1<<numbers[number].down)) { // both buttons are pressed
@@ -823,6 +841,7 @@ void main(void)
 						}
 					}
 				}
+				standby_timer = 0; // restart standby timer
 			}
 			
 		}