diff --git a/main.c b/main.c
index 32ecf46..18cc99f 100644
--- a/main.c
+++ b/main.c
@@ -1,6 +1,7 @@
 #define __AVR_ATmega2560__
 #define F_CPU 16000000UL
 #define DISPLAY PORTF
+#define TICK_BEEP true
 
 #include <avr/io.h>
 #include <util/delay.h>
@@ -36,7 +37,10 @@ void start_timer() {
 // is triggered whenever timer 1 (16 bit) overflows.
 ISR(TIMER1_OVF_vect) {
     TCNT1 = tick_timer_start;
-    if (counting) ticks += 1;
+    if (counting) {
+        ticks += 1;
+        if (TICK_BEEP && ticks % 1000 == 0 && !beep_time) beep_time = 10;
+    }
 
     if (bit_is_set(PIND, PIND0)) {
         PORTD &= 0b11111110;