This is an excerpt from M. Crocker, B. Menikheim, G. Mims, K. Harden, " HARCS: Home Automation and Remote Control System," ECE 4542: Design II, Department of Electrical and Computer Engineering, Mississippi State University, Fall 2003:

The Home Automation and Remote Controlled System (HARCS) is a system for extending the use of a home computer to solve the problem of automatically and remotely controlling home appliances. The idea for this system stemmed from the need provided by a customer. The customer wanted a way to control a garage door from a cellular phone. Her garage door opener quit working and provided limited range and efficiency when it was working. Rather than design a system specifically for opening and closing the garage door through a phone line, our team decided that a modular system using a home computer would offer more functionality at a lower cost. A modular system allows for easy expansion to accommodate virtually any appliance desired by the customer.

The goal of the Home Automation and Remote Controlled System is to offer a solution for controlling home appliances and by doing so, provide the customer with a new convenience. A customer could use this system to turn on lights and a stereo each morning to wake him or her up. It could also be connected to a coffee pot so the user can wake up to a hot cup of coffee. There are numerous applications for such a system that can be applied to satisfy each customer's individual needs.

While there are many appliances available that offer control through a network, very few of them offer a system that can provide manual, automatic, and remote operation. Currently, X10 technology is the primary source used for available home automation systems. X10 allows devices throughout the home to communicate with each other using the existing 110V electrical wiring typically installed in homes, making any rewiring unnecessary [7]. This system provides up to 256 addresses for appliances [7]. However, this is not a maximum limit for the number of devices that can be controlled. Multiple devices can be assigned to the same address to operate them all simultaneously [8].

While X10 has many available features, it also has several shortcomings. For example, there is no way to schedule specific operations to occur at certain times. If the user turns on the interior lights of the house every evening at dusk, he or she must input the operation codes every single time rather than having them automatically turn on. Also, there is no way to control the appliances remotely. X10 requires a central control pad that can be operated from within the house, but this is the only means of operating the appliances and cannot be used away from home. There is even a problem with communication among the devices in many homes due to the nature of the electrical wiring. If the units are on opposite sides of the house wiring, they can have difficulty communicating with one another because of signal collisions. The X10 signaling can also be easily interrupted by noise from appliances such as a vacuum cleaner or a microwave.