Okay so why does this return garbage:
String toprint = ""; toprint = String(micros() + "," + sensorValue);
But this works just fine:
String toprint = ""; toprint += micros(); toprint += ','; toprint += sensorValue;
micros() returns an unsigned long, "," is a string, and sensorValue is an int. But the first block of code is simpler and seems like it should work?