7.3 Hooking It Up

Plug the X10 CM11A into an outlet near your computer so that its interface cable is within reach of your computer. Because the CM11A uses a 9-pin serial connection, you will need a USB-to-serial adapter and the appropriate driver, similar to the illustration shown in Figure 23, ​The X10 CM11A interface controls the Web-Enabled Light Switch​. If you use a Mac running OS version 10.6 or higher, you can download the PL-2303 driver from the Prolific website.[71] Computers running the latest Linux distributions should have no trouble identifying and connecting to the PL-2303 interface.

Next, plug the USB-to-serial adapter into a USB port on your computer and attach it to a powered CM11A interface. You’ll need to interrogate the device for the serial port that the operating system assigned to the interface. You can do this via locating the appropriate tty device file in the /dev directory by issuing a ls /dev/tty* command in the terminal window. Easier still, load up the Arduino IDE and select the Tools→Serial Port menu option. In my case, the device name of the CM11A is /dev/tty.usbserial, as shown in Figure 24, ​The Arduino Tools menu displaying the USB serial adapter name​. Note the name of the new device path since you will need to refer to it in the Heyu configuration file.

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Figure 24. The Arduino Tools menu displaying the USB serial adapter name

Now that the CM11A is connected to and recognized by your computer, download the Heyu source code from the Heyu.org website, uncompress the tarball via the tar -zxvf heyu-2.9.3.tar.gz command. Then, perform a ./Configure;make;make install cycle to install the compiled application. If you use a Mac, you need to have the Mac developer tools installed before proceeding.[72] If you are using a Linux computer, make sure you have the necessary gcc compile and make tools installed. For example, if you are using a Debian-based Linux distribution like Ubuntu, issue sudo apt-get install build-essential from the terminal window to download and install the compiler and linker tools. Then, execute the usual ./Configure, make, and sudo make install to compile the source and install the heyu executable and dependencies on your computer.

Along with the heyu executable, a x10.conf configuration file is installed in the /etc/heyu directory. Open this file for read-write editing (ex: sudo vi /etc/heyu/x10.conf).

There are a number of options that can be set in the x10.conf file, but the one we’re most concerned with now is the serial port path to the CM11A that you identified earlier.

Use your favorite text editor to enter the serial port value that matches the location of your CM11A device. Save the file and test the settings by first launching the Heyu state engine via a terminal window with the command:

If no errors are reported, you’re in good shape since the engine daemon found the device and is running successfully in the background. You can also try entering heyu info for more details about the Heyu configuration. Now, in the same terminal enter this:

This will monitor the interaction of the CM11A with other X10 devices. Assuming you have set the housecode of the PLW01 wall switch to H3, enter this command:

That should turn on the switch and complete the circuit for whatever electrical device (such as a ceiling lamp) it is routing electricity to. You should also see the terminal window running the Heyu monitor process report the transmittal of the command:

Turn off the switch by issuing an off command to the H3 device:

If these commands fail to turn the switch on and off, try another X10 module, like an AM486 Appliance module. If that also fails, try bringing the wall switch closer to the X10 computer interface, preferably on the same room wiring. The majority of issues I have encountered with X10 projects are often directly associated with the reliability of the fire-and-forget protocol of X10 itself. If you suspect the problem may be the X10 hardware, try swapping the X10 device in question with replacement hardware. You can also have an electrician check for line noise or electrical wiring issues that may be hindering the transmission of X10 pulses from the CM11A interface to the accompanying X10 modules.

Once the computer and CM11A are talking to one another via the heyu command-line interface, we can leverage this functionality by encapsulating it into a web application. This way, we can easily access and control X10 end points from a web browser and ultimately from an Android application.