Low cost Two-Wire system with power over data lines for remote irrigation control and monitoring

Abstract

This paper describes the design and implementation of low cost two-wire irrigation system, utilizing the DC pulses to encode data transmission on to a single pair of wires which are also delivering power. Proposed two wire irrigation system consists of one central master controller and many remote decoder modules. Modulation of the digital data onto a power line has been achieved by generating alternating frequency square wave DC voltage and current pulses, in which binary data   ones and zeros correspond to a different pulse width duration. In this way, more reliable half duplex communication between central controller and the remote decoders has been achieved, increasing the robustness of the system against amplitude noises in the line. This work proposes a simple circuit to implement described system using discrete components, such as, transistors and current sense amplifiers. The paper also includes the design and hardware implementation results of both central controller and decoder modules for two-wire irrigation control system.