Although all our lights have conventional switches (well, momentary switches in conventional locations), we use a lot of X10 RF Remotes and X10 Motion Sensors to trigger lights and other devices. Initially, we used a TM13U RF Transceiver Module that receives the X10 RF signals and converts them in to X10 powerline signals. If we stopped here and let the powerline signals trigger the X10 devices directly this solution would probably be okay. However, we wanted computer control so we have another level of indirection. The powerline signals are then received by the X10 CM12U Transceiver and sent to the house computer. The computer then figures out how to react to this signal and, if the action involves an X10 device, sends another signal back to the CM12U where it is sent on the powerline.

The problem with this setup is that the X10 powerline is slow, so converting the (fast) RF signal to a slow X10 signal to get it to the computer is not very smart.

Additionally, RF devices repeat their signals which in turn get repeated on the powerline. While the repeats are going on, the computer, responding to the first received signal, is instructing the X10 Transceiver to transmit a command on the powerline. This results in frequent collisions leading to noticeable delays (and X10 powerline signalling isn't fast to begin with).

So, we purchased a W800 X10 RF Receiver and gave up on the TM13U. Using the W800 serial port receiver, the X10 RF could be read directly by the house computer. This avoids the delay and the collisions of the X10 powerline signals for the trigger and any triggered X10 commands.

The W800 was a solid piece of kit and worked very reliably. However, in the end, I replaced it with an RFXCOM RF Receiver as that was able to receive additional protocols. I expect I'll rave about RFXCOM products in future posts.

We had three significant problems. The first was noisy devices preventing the X10 powerline signals reaching some parts of our house.

Initially, we attempted to resolve the noise problems by using X10 FM10 Plug in Filter Modules or X10 FD10 DIN-mounted Filter Modules. We still use them on a number of appliances - things like TVs, fridges, laptop power supplies, UPSs, etc. They definitely help but there were still sockets that didn't get any signal. (We know because we used an X10 Signal Tester to check the sockets.)

Eventually, I came across Jeff Volp's excellent explanation of X10 problems and ordered an XTB signal booster. This device takes the X10 signal from the X10 CM12U Transceiver computer interface and boosts it by a factor of 10. This fixed our X10 powerline signal problems completely. We still occasionally plug in a new, exceptionally noisy device that needs a filter but this is very unusual.

The second problem was with X10 RF signals. When the batteries in an X10 Motion Sensor run out, they often end up transmitting excessively. This effectively jams any RF signals (including my car key buttons). Unlike most of the other RF devices we use, these devices don't report battery status so I've solved this problem by using an excellent charger, good quality rechargeable batteries and reminders to change the batteries every 6 months.

The third problem, with latency, is a bit more complicated so I'll cover that in another post.

Although I am a morning person, I still need a little help waking up in the morning. My lovely children help a bit but being able to have the lights gradually brighten to full brightness when it is time to get up helps a lot, particularly in the winter. It also means that the children wake up at the same time every day, which in turn means they tend to go to sleep pretty reliably in the evening. In the event that they wake up too early, they know it's too early as the lights aren't on yet so generally don't wake us.

We also have X10 Motion Sensors so can automatically trigger lights in rooms with no natural light. Our utility room, where we change nappies, is a good example as this behaviour is particularly useful when you have your hands full carrying a reluctant toddler.

The children rather like the low-level stick-on X10 RF Remotes that enable them to turn on their lights (and I like the fact that they don't have to climb on the furniture to reach the "normal" switches). (They also like having the remotes trigger wolf howls, T-Rex roars and Michael Rosen from the ceiling speakers.)

One disadvantage of the dimmable lights is that most dimmers have a minimum rating. The LD11 X10 DIN-mounted Lamp Modules that we use require a minimum load of 60W. This is a problem because it is becoming increasingly difficult to buy bulbs that meet this requirement. At the moment, we typically use Energy Saver GLS Lamps which look great and use just enough power to keep the dimmers happy.

I'd be very interersted to know how others with X10 solve this problem as I'd love a solution that used less power but which was still dimmable and produced a pleasant bright light.

The most important device we've automated is the kettle. We "prime" the kettle after making a cup of tea by filling it, switching it on but turning it off at the mains (with an X10 Appliance module). We can then turn it on using either an X10 RF Remote, a web interface, timers or via a number of other mechanisms. This is a real time saver. I can "C-c k" from emacs and only go to the kitchen when the kettle has boiled rather than going to switch it on and wait while it boils.

Tracy says that this is just laziness. I probably used to empty/load the dishwasher while waiting for the kettle, so perhaps she is right. She prefers the fact that you can hit a remote button by the front door when you come home on a cold day, or from upstairs before you come down in the morning, and have the kettle waiting when you get to the kitchen.

The house computer also monitors the mains current and attempts to turn the kettle off for you if it sees a drop in current usage equivalent to the kettle usage. At the moment, it's working off the whole house current usage data so it doesn't always work but it still often manages to recognize the change and switch off the kettle at the main while you are filling the kettle.

Today we decided to try unplugging the electrical items that we had recently added to the house and see if any of those made a difference. We unplugged lots of things one at a time and nothing made a difference. Then we unplugged the remaining items upstairs - and everything started working again. We plugged the items back in one by one, and everything still worked. We're none the wiser as to what was causing the problem.

When it next happens, which we're pretty sure it will, we'll make sure we unplug devices one at a time. If we can identify the culprit then an X10 plug-in filter might help.

At least we know it's not a problem with the Harmony module.