It is necessary to develop various core components for robots according to the upward trends of robot business in many fields. Especially sensors are essential to robot applications and sensor network and sensors become modular for the sake of conveniency and efficiency. In this paper, we developed a low cost sensor module which has multiport analog inputs, digital inputs, and digital outputs using I2C communication. We designed the procedures of I2C communication for extensible stand-alone sensor module and its functions. The software of the sensor module was developed using LabVIEW. It has smaller response time than existing commercial products and has good performance in acquiring analog sensor data. Two or more sensor modules can be used being connected and the developed sensor module is expected to be used in various robot applications and sensor network.