Hardware Reference
In-Depth Information
Your Own Powered Devices
Even some hardened geeks balk at the idea of creating hacks with mains electricity.
10
But with a little care and
attention, you can add control to any mains-powered device, such as water heaters, heaters, garage door motors,
and so on. To do so requires a controllable relay system, accepting a control signal and closing, or opening, a set of
contacts that allows current to flow from the plug to your unit. You can even wire them directly to standard consumer
equipment (like modems and printers) to reboot or power cycle them. There are a few options in this area.
X10 Control
Building an entire X10 unit to control a motor, for example, is so far beyond the scope of this topic that it wouldn't be fair
to try. Instead, I will show an inline appliance module, such as the AM12W, which handles the dirty work of processing
the X10 protocol and results in a set of closed contacts between two of its connections. It works in the same way as the
AM12 you saw in Chapter 1 (although slightly cheaper), but instead of controlling the flow of current to a plug socket, it
controls the flow between the mains and the X10 unit and between the unit and the device. Figure
2-8
shows this wiring.
AM12W
Brown
Blue
Black
Mains
Power
Live
Neutral
+
Device
Figure 2-8.
Connecting an AM12W to a mains-powered device
This works for any unit that is remotely controlled only through X10. To support a local switch (either in the on/off
variety or a momentary push button), a better choice of module is the AD10. This also supports a manual override on
the device, shown as the blue button in Figure
2-9
.
3INCE*ANUARYIN%NGLANDAND7ALESTHE"UILDING2EGULATIONS0ART0SPECIFIESTHATONLYCERTIFIEDENGINEERSCANCARRYOUT
THISPARTICULARELECTRICALINSTALLATIONWORK)FITNOTCARRIEDOUTBYSUCHAPERSONTHENTHEWORKMUSTBECERTIFIEDUPONCOMPLETION
/THERCOUNTRIESMAYHAVESIMILARLAWS
Search WWH ::
Custom Search