Sunday, June 28, 2009

The old and the new

I drew this diagram to show you how much better the new hinge is than the old one.

Questacon clock

I found this, and thought it was great, then I read a bit about it, and realised that it was the one my friend Gary had been telling me about. He and his team built it at Questacon's workshop just down the road from where I work.

Tuesday, June 23, 2009

My card box

If there are two types of games that I love (which there are), they would have to be billiards and cards. Last year I made this sweet, if rather chunky, card box of copper. It had a handmade hinge, and I etched a a picture of the mad hatter's tea party into the front of it. It held the cards well, was sturdy, and the bottom never fell out, not like the cardboard boxes that cards normally come in. Anyway, recently I lent it to a friend who wished to continue playing cards in their free period, something I often do, and the next thing I knew, it was gone. I had the cards, but no box. I don't know who lost it, and I don't really care anyway. It gave me the kick that I had been needing to make a newer, better one. So here it is. It's not done yet, but I've made the two parts of the box and done the hinge. Next up is to put an etching on the front. I expect I will do the same picture as before, but I'll do it better this time, the last one was a bit shallow. But I'll also etch a 500 scoring table on the inside of the lid. Unfortunately, I didn't take any photos of the old one, but I do have photos of the new one.

Here are some of the details. The top is unadorned at the moment, but the bottom has a gear from an old broken German cuckoo clock that I found soldered on to it. I made the hinges with some very small copper pipe, I cut it to the length of the (short end of the) lid, plus a little extra, then cut it into thirds. I cleaned the ends up, then put some flux on the pipes and the edges of bot the box and the lid, pushed them into position lying on a tile, and gently heated them, then added a very small amount of solder.

The pin running through the pipes is some brass wire.

The old hinges were made from copper sheet, folded into a rough tube at one end, then soldered onto the rest of the box. Funtional, but chunky and fiddly. These ones, while fiddly, were actually easier than the old ones, and are almost invisible.

Monday, June 22, 2009


Micah came over for a bit today to install an OS on the Vectra. He brought with him a Slax boot disk. This is a live session Linux OS. I have to say though, I'm not enamoured with Linux thus far. I can't find anything on it, and it can't even see its own hard drive, which we discovered is 20GB, not the 8 that I had previously thought. I use Windows normally. I accept the flaws of Windows, on the presmises that a) I know how to use it, and b) PCs are modifiable. It seemed to work okay while Micah was still here, but when I tried to put music on it as soon as he left, the hard drive was gone. I have a sneaking suspicion that I will put Windows back on it later, but we'll see.

Saturday, June 20, 2009

Vectra PC

I got a power supply for it today, 19v, 3.16A, usually used for laptops. Having arrived home, I hooked all the different bit of computer together and fired the Vectra up and, lo and behold, it worked. It turns out it's running XP professional, but only has an 8GB hard drive. That will have to be fixed. Micah and myself are going to do some fiddling on Monday. I plan to strip it down to the smallest possible amount of software. I want it to play music, read pdfs and do MS Word as well. And maybe paint. But that's all it needs. Micah has suggested using Live sessions, but we'll see.

Wednesday, June 17, 2009

Two recent acquisitions

In the past week I have obtained two quite interesting things. The first, bought from a shop on Geelong St., Fyshwick, is a fan made by General Electric from before 1950, although I couldn't find exactly when. It set me back $20, but I think it's fantastic. I intend to make it work again and set it up in the workshop for the disgusting Canberra summers that we get.

The other is a small 'corporate's' PC that I found on the side of the road. It's an HP Vectra, released in 2000, with a fast-remove, ultra-ata hard drive and DVD reader. Instead of having an internal power supply, it requires a plug pack at 19 V DC, 6.13A. I don't have a power supply to suit, so I'll obtain one and test this little machine, and, if it works, it will become a jukebox in the workshop.

Monday, June 8, 2009


I am going to make a BE reactor(Birkland-Eyde). BE reactors are used for making nitric acid out of air, electricity, and water. The basic principle is that you use electricity to strip nitrogen compunds out of the air, then you dissolve these nitrogen compounds into water, leaving you with nitric acid, or HNO3. I will post pictures and diagrams etc. as I go. So far, I have made the electrodes. They take the form of a pair of copper pipes, one inside the other, but not touching. Air will get sucked through it, making it pass through a disc of plasma in the process. From there the air will bubble through a tank of water. Here's a diagram of the electrodes:

Wednesday, June 3, 2009

Billiards and time

I was recently thrilled to discover that I am set to acquire a billiard table in the near future. Being one of those people who is always trying to improve on things that really have no problem, I decided to build a ball return system for it.

My first problem was the design, I went through a whole range of design concepts before I settled on one that looked like it would work. The other problem facing me is maths and physics. I have no idea what sort of angle the return chutes should have on them. The balls need to roll slowly enough that they aren't worn out just by being potted (sunk), but fast enough that they don't just stop altogether.

To overcome the problems that mathematics pose for me, I have come up with a piece of apparatus that will measure the speed of a billiard ball over a known distance, and a known gradient. I've had numerous designs for this too, all identical in practice, but not in implementation. The first method was to mount some micro switches in a piece of PVC pipe, 30 centimetres apart (I only had 40 cm of pipe big enough). The switches were wired in parallel with the start/stop button on a stopwatch. This means that when the ball hits the first switch, the timer starts, and when the ball hits the second, the timer stops. In theory this would have worked, but my construction was lazy and haphazard, so it promptly fell apart. the second method had a pair of wooden rails running parallel, with the same electrical set up, but the switches 1m apart, a nice round number. This should have worked too, but I discovered that by the time the ball reached the bottom switch, it was going too fast to actuate it.

Most recent plan: Same rails as before, but with an optical switch rather than mechanical ones. The circuit diagram is below, and I will put a PCB layout somewhere too, when I've worked out the kinks. It's not a sophisticated circuit, but it works (at least, it did on the prototyping board), and that's all that counts at the moment.

The switching transistor is a BC548. The resistor in the circle is a Light Dependent Resistor (LDR), and the Diode with the lambda next to it is a LASER diode. The 7803 is any 3 volt regulator for the LASER diode, not necessarily a 7803.
You may have to fiddle with the dimensions of the layout to get the right sizes, and you will have to invert the colours if you are going to use toner transfer to fabricate your board.

On a different note

Up until now, my blog has been primarily an assessment piece for school, one of the requirements being that it have a common thread running through the whole blog. I 'handed it in' last Friday, but have decided to keep blogging. From here on out, my blog won't be just about etching. It will still be mostly about things I'm building or making, but it will have the odd opinion or social commentary as well, I expect.