diff --git a/cubesatsim/cubesatsim.h b/cubesatsim/cubesatsim.h
index 52635916..ddda843d 100644
--- a/cubesatsim/cubesatsim.h
+++ b/cubesatsim/cubesatsim.h
@@ -373,6 +373,8 @@ RPI_PICO_Timer ITimer2(2);
 
 bool timer0_on = false;
 bool timer2_on = false;
+int timer0_number = NULL;
+int timer2_number = NULL;
 
 char callsign[20];
 int morse_timing = 60;  // ms for a dit