Apress - Smart Home Automation with Linux (2010)- P9:Linux users can now control their homes remotely! Are you a Linux user who has ever wanted to turn on the lights in your house, or open and close the curtains, while away on holiday? Want to be able to play the same music in every room, controlled from your laptop or mobile phone? Do you want to do these things without an expensive off-the-shelf kit | CHAPTER 1 APPLIANCE CONTROL Computer Control But far the most powerful and creative device available is a computer interface such as the CM11 as shown in Figure 1-14. This is a transceiver that s able to pass messages from the power line to the computer and send messages back from the computer onto the power line. Unlike most X10 devices the power socket on the CM11 is not controllable by X10 and instead is a simple through port. Consequently if you want to control your computer with X10 you have two options. Caution Be wary about putting the computer s power onto the normal house code because you might accidentally switch it off when issuing an all units off message. First you could assign the computer an unused unit code and configure the computer to issue a shutdown command when it is seen on the power line. I ll show you how shortly. Second you could use a separate appliance module and simply plug the computer into it. This is a workable although poor solution since you re likely to have the machine plugged into an uninterruptible power supply unit UPS . Figure 1-14. The CM11EFL In addition to being a controller this device can also act as an event scheduler and message-relay system even when not connected to a computer. Therefore you can use the software that is the supplied Microsoft Windows version or a Linux equivalent such as Heyu to program the device and let it run stand-alone since this programmed information now lives within its own EEPROM which retains the data even if there is no power allowing it to be moved from one place to another without reprogramming. This also means it s possible to have a slightly automated house without a single computer However you must keep a copy of the file and data that you uploaded to the CM11 since it is impossible to download it from the device. 23 CHAPTER 1 APPLIANCE CONTROL Caution When unplugging the CM11U from either the mains or the computer always remove the serial cable from the device first because stray .
