My thesis was planning an Arduino platform-based modular hardware and software, which makes easier the developers job. I have studied similar projects, which also had a modular hardware construction, and investigated the possibilities of wired communication between the modules. The modules offering different function, which can be accessed and used with the help of the controller. The controller automatically recognizes the connected modules, so after joining the developer does not need to care about the low-level hardware join. The controller can use the capabilities of the modules, or may pass to an external server. I designed and implemented the controller, an actuator and a sensor module. I realized while investigating the further potential use of modules, that they are not only useful for connecting sensors and actuators, but also to extend the limitations of the Arduino hardware, so a complex function can be executer at the external module, and the controller can use the output of it. I planned and constructed a functional module as well. Then I examined the possibilities of energy saving at the modules. I made the projekt in C ++, to the AVR ATmega328 microcontrollers based Arduino platform. With the help of the completed modules the developement is much easier and more convenient on the Arduino platform.