diff --git a/radio/src/opentx.h b/radio/src/opentx.h
index bafc0517d..a5216a0a5 100644
--- a/radio/src/opentx.h
+++ b/radio/src/opentx.h
@@ -396,12 +396,12 @@ extern uint8_t channel_order(uint8_t x);
   #define ROTENC_DELAY_HIGHSPEED       16
 #endif
 
-#define HEART_TIMER_10MS               1
-#define HEART_TIMER_PULSES             2 // when multiple modules this is the first one
+constexpr uint8_t HEART_TIMER_10MS = 0x01;
+constexpr uint8_t HEART_TIMER_PULSES = 0x02; // when multiple modules this is the first one
 #if defined(PCBTARANIS) || defined(PCBHORUS)
-#define HEART_WDT_CHECK                (HEART_TIMER_10MS + (HEART_TIMER_PULSES << 0) + (HEART_TIMER_PULSES << 1))
+constexpr uint8_t HEART_WDT_CHECK = (HEART_TIMER_10MS + (HEART_TIMER_PULSES << 0) + (HEART_TIMER_PULSES << 1));
 #else
-#define HEART_WDT_CHECK                (HEART_TIMER_10MS + HEART_TIMER_PULSES)
+constexpr uint8_t HEART_WDT_CHECK = (HEART_TIMER_10MS + HEART_TIMER_PULSES);
 #endif
 extern uint8_t heartbeat;