This work focuses on the design and implementation of a microcontroller for apply all the knowledge acquired during Engineering Electronics career. In order to improve the knowledge about RF technologies, security system have been created, which increases the number of applications used in these days. This design utilizes light sensors as the end device for detecting any changes of resistance. The results show that the designed system can send and receive data until 100 meters of distance between module sides (receiver-transmitter). This security system designed using PIC 16F84 microcontroller as entire brain of the system with sensors, has been successfully designed and implement considering some factors such as economy, availability of components and durability in the design process.