Apress - Smart Home Automation with Linux (2010)- P7 ppt

CHAPTER 1 ■ APPLIANCE CONTROL 13 back-EMF generates a large voltage spike that can blow the fuse in the AM12U (if you’re lucky) or the device (if you’re unlucky). Figure 1-7. The AM12U, 52 × 122 × 33mm There is an in-wall version of this, called the AW12U, with a similar specification. ■ Note You can often use these devices to automatically power-cycle routers and modems when the Internet connection is unavailable, often from the router being choked or when it simply crashes. Appliance MicroModule (AWM2) This is the same module featured previously (and in Figure 1-6) as a suitable candidate for light control, because it can also be used to control appliances. Apart from its smaller size (46 ×46 ×18mm), its main benefit over the AM12U is that it has a much higher power rating, making it possible to power fan heaters and their ilk. The given power specification on this unit is 2kW for incandescent lamps, 3A for inductive appliances, and 16A on resistive loads. CHAPTER 1 ■ APPLIANCE CONTROL 14 As mentioned previously, this device is mounted in wall outlets, making it more difficult to circumvent. Consequently, this module allows you to switch off a child’s TV or stereo system at night without them simply unplugging it, as they might with an AM12U. Table 1-1 gives a breakdown of the previously referenced devices. Table 1-1. Basic X10 Modules Appliance Name A M12U A ppliance Module (plug) A WM2 A ppliance MicroModule (in wall) LD11 DIN Rail Dimmer LM10U W all Switch LM12U Lamp Module LM15EB Bayonet Lamp Module LM15ES Screw-in lamp module LWM1 MicroModule with dimmer LW12 In-wall module with dimmer (like LWM1, but no two-way comms) TMD4 MicroModule Transmitter Dimmer (four-switch, in-wall, no power handler) Internal Devices These devices are rare and usually fit in the novelty category. One good case is REX-10, a barking dog alarm system! Upon receipt of a suitable X10 message (for example, from a motion detector), this device plays the noise of a dog barking followed, a few moments later, by the sending of an X10 message to switch a light on. As an idea it’s good, but it is very difficult to configure these hardwired devices as effectively as you could with a short computer program or simple script. Combination Devices I’ll briefly cover some devices that, although they are not supplied with X10 control, are invariably used with it. It should also be noted that the mains control could equally well come from an alternative power control method (for example, C-Bus). CHAPTER 1 ■ APPLIANCE CONTROL 15 Electronic Curtain Rails: Retrofit You can automate many curtains by simply wrapping the U-shaped pulling cords around an electric motor. Naturally, the devil is in the details, so there are a few prebuilt motor and pulley systems on the market that are able to open and close curtains, mounted into a head rail. They include the Regency PowerMotion, Universal Curtain Motor (UCM), and the Add-a-Motor 80 (CM80). Using a retrofit solution requires you to have a good existing head rail, because this determines the maximum weight of the curtain the motor is able to handle—if it gets stuck, then the motor could burn out. The specific weight will vary between devices, but a good guide is that head rails with ball bearings will manage curtains up to 30 kilograms, while those without might stop at 10 kilograms. All these devices require manual installation to fix the cords to the motor, configure the open and closed positions of the curtains, and adapt the electronics to incorporate a separate X10 receiver. Depending on the device, this might involve a simple AWM2 or AM12U unit or possibly an in-line module. Controlling the curtains once installed is a simple on/off affair, requiring some additional control logic to automatically position them as “50 percent open,” for example; however, you can always issue an “off” command manually to stop them from opening any further. There are switches designed specifically for curtain control, such as the Marmitek X10 Motor Drive Switch (SW10), which repurposes the standard X10 messages of “on,” “off,” and “bright” to be “fully open,” “fully closed,” and “partially open,” respectively. ■ Tip You should not leave control curtains unattended in the first few days after installation, because the motor might try to move them too far and burn out. Electronic Curtain Rails: Prebuilt One such solution here is the Silent Gliss AutoGlide. This provides a made-to-measure curtain track with a premounted motor and a remote-control unit. Since the curtain track is custom made, you must know in advance the size and shape of your window since DIY adaptations are not possible and bending it (to fit in a bay window) is possible only by the manufacturer. The motor can be controlled by an X10 appliance module using a similar amount of DIY to the retrofit versions. Stand-Alone Controllers Having lots of remotely controlled lamps and appliances isn’t much use unless you have some way of controlling them. All the devices covered in this section contain an X10 transmitter in some form that places an X10 data message onto the power lines, which is in turn picked up by any of the X10 modules covered previously. Tabletop Transmitter Modules These modules all provide a way to send X10 messages from a basic keypad to a specific device. Since they are powered by mains, the signal can be placed directly on the power lines, avoiding the need for an CHAPTER 1 ■ APPLIANCE CONTROL 16 RF-to-X10 gateway. This group supports the largest selection of devices, with each adding its own unique selling points. I’ll cover only a small selection here. Mini Controller (MC460) This is a standard, but functional, wired device that supports eight units, switchable in two banks (1–4, 5–8), along with the standard “all lights on”/“all units off” options and brightness control. To reduce the button count, the brightness control only affects the most recent lamp switched, either on or off. This is fairly standard among most transmitter modules. Sundowner Dusk/Dawn Controller (SD7233/SD533) On the surface, this appears like the standard mini controller earlier, wired to the mains, with control for eight devices, along with “all lights on”/“all units off” and brightness control. However, it also includes a light sensor that will switch on a predetermined group of lights when it gets dark and turn them off when it’s light again. These brightness settings can be tuned with a little trial and error, although with dusk and dawn changing throughout the year, this can’t necessarily be used as a natural wake-up call. Mini Timer (MT10U) This device, shown in Figure 1-8, solves the dusk-’til-dawn problem by using a timer rather than a sensor. This allows you to control up to eight light or appliance modules but lets you preprogram only four of them, making them turn on or off (up to) twice a day. This allows you to mimic a “lived-in” feel for the house. Furthermore, it includes a randomize option, which will vary the programmed times by 30 minutes to give a “human lived-in” feel. This device can also double as an alarm clock. Both this and the previous device alleviate the need for a computer server, because they can send out predetermined messages according to (simple) logic. Figure 1-8. The MT10U, 55 × 150 × 110mm CHAPTER 1 ■ APPLIANCE CONTROL 17 Maxi Controller (SC2800) This device, although designed as part of a security system (MS9780), can also provide full wired control of all X10 devices in the house and is shown in Figure 1-9. Although it doesn’t have any timing functionality, it does have a telephone socket that allows you to dial in from outside and switch lights on or off (by entering the unit code using a Touch-Tone phone, followed by either the * or # key, respectively). Figure 1-9. The SC2800 provides easy access to your light switches via telephone. Table 1-2 summarizes these desktop devices. Table 1-2. Desktop Controller X10 Modules Desktop Controller Name MC460 Mini Controller (4 ×2) MT10U Mini Timer SC2800 Maxi Controller SD7233/SD533 Sundowner Dusk/Dawn Controller (8) . LM15ES Screw-in lamp module LWM1 MicroModule with dimmer LW12 In-wall module with dimmer (like LWM1, but no two-way comms) TMD4 MicroModule Transmitter Dimmer (four-switch, in-wall, no power. or stereo system at night without them simply unplugging it, as they might with an AM12U. Table 1-1 gives a breakdown of the previously referenced devices. Table 1-1 . Basic X10 Modules Appliance. solution here is the Silent Gliss AutoGlide. This provides a made-to-measure curtain track with a premounted motor and a remote-control unit. Since the curtain track is custom made, you must