tailieunhanh - Smart Home Automation with Linux- Part 7

Smart Home Automation with Linux- P7:I will end on a note of carefree abandon—learn to steal! Once you’ve learned the pieces of the puzzle and how to combine them, there is very little new to invent. Every new idea you discover is a mere permutation of the old ideas. And ideas are free! Every cool feature discussed on TV shows or presented in the brochures or web sites of commercial HA companies can be taken, adapted, and implemented with the information presented here using very little effort | CHAPTER 1 APPLIANCE CONTROL Note You may need an IR bypass kit when passing IR signals over coax cables because the messages get muddled when passing through distribution amplifiers. IR-RF-IR Gateways These devices relay IR data through the air at the 433MHz radio frequency used by so much wireless equipment before being replayed. For these devices you have a choice between IR-only transmissions and TV senders. An IR-only transmitter such as the Powermid XL is the simplest of these devices and will allow you to remotely control devices without installing cables or sockets. They are fairly cheap but pass only IR data so the controlled device must be able to have an impact on you when you re in another room. TV senders are the wireless versions of the over-the-aerial cables or old TV distribution systems which involved an aerial amplifier and a separate aerial cable into each TV in the house. The TV sender takes a single input and transmits it to whichever receivers are listening encoding whatever IR signals it also saw. There are many variants on the market including those with SCART sockets instead of the oldschool coaxial aerial sockets and RCA composite video. Even the cheaper models often have a channel switch on them allowing multiple receiver-transmitter pairs to be used in the same house without the signals getting mixed up. And with these devices becoming more mainstream some are almost as cheap as an IR-only transmitter with the TV functionality becoming a free bonus feature. IR Over IP It is also possible to send data over your existing Ethernet cables using devices such as the Keene IR Anywhere over IP KIRA . This eliminates any distance or interference issues you might get from the other methods and also provides a way of remotely controlling IR devices from a computer without needing to have the computer and its IR transmitter physically in range of the device. Being IP-controlled also means that IR signals can be sent via the Internet. Although this is