tailieunhanh - Apress - Smart Home Automation with Linux (2010)- P31

Apress - Smart Home Automation with Linux (2010)- P31: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 4 HOME IS HOME The biggest downside with these machines however is the lack of bravado when demonstrating your HA setup to friends. After showing how you can e-mail your light switch send a text message to your video and have your own home web server opening a cupboard to show a small box that fits inside your hand is often a letdown for the male ego Custom Embedded This group features both system-on-a-chip SoC machines and single-board computers SBCs of which there are many including the Mini-ITX machines you saw earlier and the NSLU2 from Chapter 2. There are as many combinations of devices as there are uses for machines so each needs to be considered on its own merits as the various components one often considers standard on a PC such as a keyboard mouse and monitor are not available on all SBCs such as the Also some machines such as the NSLU2 can have issues with seemingly normal peripherals like USB hubs and refuse to work with them. Consequently these types of device are usually better suited to client machines in confined areas of the house rather than servers because the server will be running a wide range of software where any annoyances of hardware incompatibility will generally outweigh the benefits of size. Power Consumption For many home automation is likely to be the first time you need to consider the total cost of ownership TCO of a machine by factoring in its power usage. This can be computed empirically by using an electricity usage monitor like Kill-A-Watt products special P4400 . Such a device can be plugged into the wall on one side and the computer on the other to determine the power it s using at any particular time. This will vary depending on whether it s in the following states Idle Playing optical media Processing media playback recording and transcoding all differ Being used as a desktop machine Knowing this information can help you calculate its running cost by multiplying the .