     ShowTime_ms = TickTime;
     InterruptState = IRQ_NONE;
 
-    attachInterrupt (0, WheelRev, RISING);//pin 2 on Mega
+    attachInterrupt (1, WheelRev, RISING);//pin 3 on Mega
     SerialMonitor.print("TickTime: ");
     SerialMonitor.print(TickTime);
     SerialMonitor.print(" OldTick: ");

#define SerialOdoOut  Serial3
#define SerialMonitor Serial

#define WHEEL_DIAMETER_MM 397
#define MEG 1000000
#define MAX_SPEED_KPH 50
#define MAX_SPEED_mmPs   ((MAX_SPEED_KPH * MEG) / 3600)

void LogData(unsigned long commands[7], SerialData *sensors)  // data for spreadsheet
{
     Serial.print(sensors->speed_cmPs); Serial.print("\t");
     Serial.print(sensors->speed_cmPs*36.0/1000.); Serial.print("\t"); // km/hr
     Serial.print(sensors->angle_deg); Serial.print("\t");
     Print7 (true, commands);
}
