Can I use the SoftwareSerial rather than HardwareSerials ?

[sajuuk]

my hardware serial pin 0 and 1 have already been used,so what can I do to use the software serial?

[emnul]

I would try editing the driver so that a SoftwareSerial object is passed in for the serial object defined in RPLidar.cpp and RPLidar.h instead of HardwareSerial. You might need to make a few changes elsewhere too.