If you need to monitor distant objects you probably would go with wireless transmission. This project simply demonstrates a standard setup of RF data transmission channel using cheap 433MHz or 315MHz modules. They are connected to PIC16F877 microcontroller using HT640 encoder on transmitter side and HT648 decoder on receiver side.
With encoder you don’t have to take care of formatting data packets. Decoder in its hand automatically encodes data from received packet. Microcontroller only has to read it and perform its own actions. In this particular example there are two sensor data transmitted – LM35 temperature and potentiometer value. Set up simply monitors continuously and updates parameter change.