7.1 What You Need

X10 is a company that has been selling its proprietary electrical switches for many years, and the technology has changed little since its introduction over thirty years ago. Yet regardless of its age, X10 power switches are still a primary home automation technology, mostly because they are inexpensive and, when coupled with a computer, can send and schedule power on/off events.

Instead of relying on X10’s rigid and proprietary Windows-based application to control X10 devices, we are going to use a freely available open source utility called Heyu. Created and maintained by Daniel Suthers and Charles Sullivan, Heyu provides a command-line interface to monitor and send a variety of X10 commands to the CM11A. These instructions will then be relayed to the specified X10 switches.

For this project, it is best to stick with the Linux or Mac operating system, since they can easily compile the source code without modification. Unfortunately, there is no native port of Heyu available for Windows, and none is planned anytime in the near future. If you are using Windows, consider running a Linux distribution in a virtual machine using a program like VirtualBox.[62]

You will need the following parts (refer to the photo in Figure 22, ​Web-Enabled Light Switch parts​):

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Figure 22. Web-Enabled Light Switch parts

1. X10 CM11A computer interface[63]—note that unlike the serial port-based CM11A, the newer X10 CM15A model connects to a computer via USB and will not work with Heyu software. See the Heyu FAQ for more details.[64]

2. X10 PLW01 standard toggle wall switch

3. Serial to USB interface cable

4. An Android OS phone or tablet device (used to run the Web-Enabled Light Switch client application)

5. A computer (not shown), preferably Linux or Mac-based, with Ruby 1.8.7 or higher installed

Additionally, you will need the following software:

• Heyu 2.9.3 or higher[66]

• Ruby on Rails 3.0 or higher[67]

• The Eclipse IDE[68]

• The Android SDK 1.5 or higher[69]

• The Android Development Tools (ADK) Plugin for Eclipse[70]

At the heart of any computer-assisted X10 setup is the control module. The module provides the interface between the transmission of instructions to X10 devices as well as for the notifications of triggers (ex: motion detection) from X10 appliances equipped with such capabilities. Several of these interfaces exist, such as the X10 Firecracker (known by its serial number as the CM17A) or the original X10 computer interface, the CM11A. Most of the open source X10 automation software available today supports both of these and other interfaces, but I find the CM11A to be the most prevalent. Hence, I recommend using the CM11A for this project.

With the required hardware and software in hand, let’s take a look at how we are going to combine all this technology to make it turn a light on and off from an Android smartphone application.