and universal expansion System. It is based on the two wire I2C-Bus, which allows you to connect up to 127 devices to the Robot. You can add several expansion modules on top of the Robot, which can be mounted symmetrically on front and rear. AREXX Engineering plans to release several expansion modules with additional sensors in the near future. Of course, there is already the Experiment module for your own circuits included with the Robot and also available seperately (Conrad Electronics odering code: 191537).