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.

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.

Proposition

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:

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.