if (Serial1.available() > 0) // If there is something in the Serial port it means the reader "heard" a sensor
{
for(int i = 0 ; i < 34 ; i++) // Fill "frame" variable with entire contents from sensor.
{
frame[i] = Serial1.read();
delay(1);
If there is one byte, read all 34 of them. How's that working for you?
The Pro Micro has only one hardware serial port. Why are you using Serial1 to reference it?