An Exclusive-Or gate

Both showed up, but there was war anyway. It's odd and not a little sad that, after all the big things that have gone wrong, all the carelessness which I'm sure plagues any project like this, and the various last-minute changes and compromises that have happened, that the most stressful incident concerned a minor cosmetic alteration. A two-day shouting match between us and the electricians was resolved by one man and three minutes' work with a screwdriver.

It concerns the two switches which control the light at the end of the kitchen. It seems logical to us that when both switches are off, the light is off. Logic dictates, therefore, that when both switches are on, the light is also off; and when one is on and one is off, the light is on. I'm no electronic engineer (if I were I'd have saved myself a lot of bother this past few months) but I know an XOR logic gate when I see one.

Our electricians disagreed. They had the switches wired in reverse, so that one switch had to be off and one on for the light to be off. Since both switches shared a plate with others, it meant that the switches were not in a uniform position when all the lights were off. The electricians were adamant that this was how every two-way switch worked, and that there was no other way it could be. A demonstration that the two-way switch they installed for the landing light worked differently, i.e. correctly, did not register. I ran up and down the stairs for about two minutes yelling "Both switches up; light is off. I put this one down; light comes on. You put that one down; light goes off -- this is what we want in the kitchen!", but I may as well have been speaking Sanskrit. Blank looks.

The situation got louder and eventually they broke. One of them took his screwdriver, made the change to one of the kitchen switches, and it was resolved. They still protest that our kitchen light switches are wired in a unique and perverse way. What do you do?

While he was fixing that, we had moved on to the sensor light. They've hooked it up in a way that makes it impossible to switch off: it's either in sensor mode or fully on. This won't do. The head spark is investigating two options -- one involves an on-off switch for the whole sensor array, which will allow the existing switch to act in a simple on-off capacity for the lights; or an amendment to the system whereby the existing switch selects between sensor mode and off mode, without a permanent-on option. I can't express how surprised I am that no-one in the world has ever wanted to switch their sensor lights off before, especially given that I've lived in two houses where it has been possible, one of which I wired myself with a light I bought for a tenner.

Next, we brought in the plumber who was standing by in embarrassed silence. We arranged the placing of some electrical plumbing accessories around the utility room. The proposed drawings for this area have arrived from the kitchen people and they're due out to take final measurements on Tuesday. Ideally, though, I'd like the applicances installed first, to bring an end to the three-hour round-trip misery of laundrette visits.

And with all that sorted, we left, taking big deep breaths. On our way out we met the tiler, who spent the day grouting the kitchen and utility room tiles. So the kitchen now looks like this:

Not long to go at all here.

I was very glad that I hadn't decided to move into the TV room yesterday, since that's where our appliances went to make space:

The tiler was also busy upstairs, having put a floor on our bathroom:

We decided this morning we're going to tile the side of the bath as well. You can see the soil pipe for the toilet has been moved, away from the corner it was previously jammed into.

The outside plumbing for this is still being installed: