The pulseIn() function reads the echo pin and will start measuring the duration of the pulse when the signal changes from HIGH to LOW. When the signal goes back to HIGH, pulseIn() returns the sound wave travel time in microseconds.
The pulseIn() function reads the echo pin and will start measuring the duration of the pulse when the signal changes from HIGH to LOW. When the signal goes back to HIGH, pulseIn() returns the sound wave travel time in microseconds.