Appliance Control: Making Things Do Stuff - Smart Home Automation with Linux and Raspberry Pi - page 8

Bayonet Lamp Module (LM15EB)
This is also a simple zero-installation device but one that requires slightly more configuration. To install it, you plug
it into an existing light socket and then reinsert the bulb (up to 150W) into its free end. Neither fluorescent lamps nor
low-energy lamps should be used, though. The address is set by turning the lamp off and on again and then pressing
the required house/unit code on the controller three times, once a second, within 30 seconds of it being switched
back on. The light will come on once the code has been learned. There is also a screw-in version of the same device
(LM15ES, with ES standing for Edison screw ), although it is the bayonet version (LM15EB) that's shown in Figure 1-2 .
Figure 1-2. The LM15EB, 45 × 45 × 95mm
LM15EBs lack the dimming facility of the larger LM12U, but because they extend only 62mm farther than a
traditional fitting, they are small enough to hide inside most lampshades, allowing the room to maintain its existing
aesthetic qualities.
Again, the module acts like an AND gate, allowing the light to shine only when both the X10 command for “on”
has been sent and the light switch would normally be on.
Wall Switch (LW10U)
As you can see from Figure 1-3 , these are complete replacements for a standard light switch, which means you are
limited in styling to white plastic. However, they are easy to fit into existing recessed switch boxes with only 16mm
protruding from the wall. The unit's address is set from a pair of dials placed behind the rocker switch and can be
accessed by gently prying it off with a screwdriver. Care should be taken, however, because the plastic lugs that hold
the switch onto the case are quite flimsy and would only suffer three or four removals before breaking.