Switcheroony

I've come up with a really simple circuit to allow me to turn the lights on and off either in the garage, or in the house:



The idea is to use a relay that will stay on given current limited by R1 (I used 100ohms with a 12V supply and a 12V relay). The relay is wired to latch. To switch the device on a switch bypasses the latch contacts turning the relay on (which then stays on from current through the latching contact). To switch it off another switch shorts out the relay coil. I used momentary contact rockers from DSE, which look quite nice. You can add as many extra switches as you wish, and a computer can switch either way using a suitable buffer such as a 4000 series tri-state buffer or a pair of transistors.

The second pole is the light circuit pole. I used a 240V rated 5A DPDT relay, which cost me about $5. The power supply can be shared with other devices and the circuit produces very little noise (considering its got a relay). If you shared lots of these devices on the same power supply you could switch multiple lights using a single switch using a diode from each circuit to avoid loops.

The circuit has some nice properties:

• It is quite robust, as the relay and resistor can take a lot of abuse.
• The signals are sent via reasonably high current making the system quite noise immune.
• It is very simple to assemble and debug.
• It interprets set and reset as a reset.
  
• It starts in a known state, off.
• It uses no current when the light is off (ignoring power supply).
• You can read the current state looking at the switching lines, so you can use a suitably low current indicator at the remote end (perhaps a buffered LED). If you only have a few switches you can probably get away with just a LED from switching to ground at each rocker.
  

All in all, a very nice design. The only thing I'd like to extend it would be to make the local switch (the one on the wall for the light) look like a normal switch, and to actually be the relay itself so that the switch displayed the current state. With that you'd have a very elegant home automation system.

What complete rot

A few weeks ago I noticed a bracket fungus growing on one of the window panes. I was a little worried, and looked it up in a fungus book. Phew, it wasn't the dreaded dry rot, just a wet rot. I figured it probably only went as far as the window frame.

A week later I decided to open the window to let some fresh air through the garage. The window pane dropped out of the frame. I though, ah well, lets see how bad it is. Big mistake!

This evening I spent a good hour scraping out and painting all the rot in the structural timbers of my garage. We had intented to spend the evening installing the new cladding, but I ended up spending my time repairing damage.

The problem is that the previous owner noticed that the weatherboard cladding was rotting. And decided that the best solution was to cover over it with cheap vinyl fake weatherboard. As a result the fungus, which was established in the corners, decided to venture out into the structural timbers as well.

As a result, I've decided to fix the garage up properly. This means pulling off all the vinyl, pulling off all the rotted weatherboards and fixing the frame. As I delved deeper into the garage I came to the realisation that the previous owner was definitely from the if it ain't visibly broke, don't fix it school of house maintanance (I am now quite scared of what I'll find under the house cladding). The roof leaked into the wall space, so he nailed some plywood over that to hide it (this wasn't just to sell the house, the plywood itself has been there at least 5 years and badly rotten too). The corners have all rotted away completely, so he replaced them with some pine(!) and nailed some cement sheet over the top. And when that started looking tatty he nailed more cladding over the top.

Thankfully, after spending a good hour tonight I've removed and replaced the problems on one corner and 2 sides. We should be able to attach some of the cladding tomorrow after I've restored the drainage trench around the outside.

I'm going to replace the two small glass windows with a double glazed polycarbonate window the full length of the window space. (I'm using twinwall polycarbonate mainly because then I don't need a strong frame for it, and because I am planning to put an airconditioner in the garage for those cold winters and the height of summer). I'm beginning to think that despite all the claims of the passive solar mob a well insulated window on the south side is pretty good. In summer it doesn't let any hot sunlight in, in winter it gets a lot of light from the sky - particularly if it is overcast. It also suits my garage layout a lot better :)

I've now installed all the power into the garage and had steve check it over and do the paperwork. It's nice to have all my bench tools ready to go at a flick of a switch rather than requiring me to rummage around looking for the extension cord.

A modest manor

G'day all!

Welcome to a Modest Manor.



(if I was being really tricky, I'd link that to one with an open door and have a slideshow of the inside of the house...)

Woo hoo! A new house blog! This blog is for us, to see how far we've come, and for you to laugh at the things we've done.

Today was an interesting day. It rained, a lot. It rained more today than it has for the rest of the year. This rain fell because Nathan pulled the cladding off the southern and western garage walls over the last few days.

As the rain fell, we loaded up the trailer with old vinyl cladding (I keep typing that as clagging) and weatherboards.

$50 to tip the blasted stuff! We only had $55 between us! On a scale of 1-10 of good tips, this one rated about a negative five. No signs, no indication of where to dump stuff - you just drive out over everyone else's (non-perishable) rubbish, pray the tyres don't find something sharp and then get bogged in a soggy patch.

Yep, we got bogged. We had to lay the old cladding and weatherboards out around the back wheels of the car, after taking the trailer off. Not taking the trailer off would've been disastrous - going backwards would've jack-knifed the thing and if we were pushing the car from behind to get it out, the trailer would've run us over....

So Nathan and I pushed the car and D reversed it, and all this smoke rose up from the back wheels, scaring the crap out of us, as they burned rubber and paint on the vinyl cladding, but we got it unbogged!

I am still covered in tip muck.

We cleaned the rotten bits out of the hardwood frame (chisels are wonderful things!) and Nathan treated the areas with an antifungal copper solution. Now we can put the sisalation on and then put the polystyrene cladding on and render it.

Simple eh? LOL

anon!