Short description of MOBOTSIM 1.0: Configurable 2D simulator of differential drive robots. It provides a graphical interface representing an environment where robots and objects can be easily created and edited. It has a BASIC Editor in which the user can write macros making use of specific functions to get information about robots and sensor data and to set speed and driving data for them as well as making use of all the power and ease of BASIC language to develop simulations.