Home Automation

Cover of the Aug/Sept 2001 issue of Home Automation Magazine.

Few of us can afford a butler. Fortunately electronics and technology can compensate for this by allowing us to remote control many devices in our home. However, home automation does not mean just being able to control your home's appliances from a distance, but also includes intelligence in the system to better serve our needs.

The first requirement is communication among the various subsystems. In my system, this is mainly performed by a communication standard by a company known as 'X-10'; its protocol is known by that same name. In addition, I have a EIA/RS485 network running to my various computer systems for higher bandwidth data. The second requirement is a system controller that can 'tie in' all the system components and make them work harmoniously. This is met by a X86 class desktop running a custom program.

This centralized system can control almost all of the lights in my home, a few appliances, the garden irrigation, some window treatments, the Audio/Video system, the security system, and the HVAC (Heating Ventilation and Air Conditioning). I can communicate with the central computer by using keypads throughout the house, any phone in the world (including those inside the home), any browser over the internet, and from my wrist watch. A webcam (with integral pan/tilt) allows me to see what is happening with nothing but a web browser.

My main controller (the PC) communicates with smaller nodes on a twisted pair EIA/RS485 network. Each node performs a particular communication or control function, and is based on the PIC microcontroller by Microchip. You may wonder why I chose to build my own system. In addition to being less expensive, it also allowed me to learn a great deal about micros and GUI programming. Both of these areas have benefitted my professional life as well.

This home automation system was featured in the:

Jan/Feb 1999 issue of Home Automator Magazine

(electronic version of above article),

and the Aug/Sept 2001 issue of Home Automation Magazine

(electronic version of above article)

and the Fall 2004 Book "Smart Home Hacks" by O'Reilly Publications

Perform a search for a keyword on www.edcheung.com

Here are the components of my system:

The central controller and user interface. Previous controller software.
The communication network
The X-10 and IR node
The phone and voice node
The Thermostat nodes.
The weather node and rain collector
Power Line monitor
Water meter monitor
Water Heater monitor
The security node and Smoke Detector Interface
Web to X-10 Interface
XTB-IIR X-10 Signal Transmit Booster and other ways to improve signal quality

Other related components:

Web TV Server
The Motorized Web Cam
The Backup Electrical Generator
DSL (Full time broadband Internet) connection
The motorized window treatments
The garden irrigation system
The Whole-House Audio/Video system and CCTV cameras
The Infra Red relay
The No hum fan controller
The Central vacuum system
My wrist watch controller
The telephone system
The wiring system and computer network
The PCS Scenemaster Lighting Controller
The Firecracker Protocol
The PIC Web Servers
The Real-Time Radon Monitor
Heated Bathroom Seat
Water Intrusion Alarm
Projection Atomic Clock
X-10 Signal Monitor

Bluetooth interface for embedded processors