Nexus Robot Lib

This is for Nexus Robot Lib. Its Arduino library and document are hard to find. So here they are.

To add LiDAR sensor, a suggestion is XV LiDAR from Get Surreal.

To use SLAM, a simple script to use is BreezySLAM. To try it, we first need to install xvlidar Python package, and then use example/xvslam.py.