I have this video camera, a Sony DVD201E which records straight to a mini-DVD disc. I want to copy the recorded video onto my PC but the software which comes with the camera is pretty awful. Besides it is Windows-only and I do prefer to use Linux.

So I have made a little Linux app which can extract scenes from a DVD disc. The camera records each scene as a DVD “chapter”. My application reads a DVD disc and copies each chapter into a separate MPEG file. I’ll publish it here in case anyone else finds it useful.

Downloading and Compiling

I’m just releasing this as source code at the moment. I have tested it under Ubuntu 7.10 but It will probably work fine on any UNIX-based system. You can download it here:

DvdChapterExtract-1.2.tar.bz2 (16k)

You will need libdvdread and libavformat before you compile. So install those:

sudo apt-get install libdvdread-dev libavformat-dev

Next unpack and compile:

tar jxf DvdChapterExtract-1.2.tar.bz2

cd DvdChapterExtract/Release

make all

Usage

1. You need to record your discs in Video mode, not “VR” mode. VR is a Sony proprietary format which cannot be read in a regular DVD drive.

2. After recording your disc, you must Finalize it in-camera.

3. Put the disc into the DVD drive on your PC.

4. Launch the DVD chapter extract tool like so (assuming /dev/scd0 is the name of your DVD drive).

./DvdChapterExtract -d /dev/scd0

It will extract each chapter into a separate file called chapter001.mpeg, chapter002.mpeg and so on. These can be loaded directly into any video editing software.

The camera also tags each chapter with some meta-data such as the date and time the scene was recorded. I have not yet figured out how to read that data.

My last few articles have been very technical, so to slow the pace down a little, here’s an Apple Crumble I made the other day. I was kind of winging it but it turned out pretty good. I’ll write it here so I can remember the recipe.

Before you start, preheat your oven to 180°.

The Apple

• 850g Apples (I used “Pink Lady” apples but any kind would probably do)
• 2 tablespoons Brown Sugar

Core the apples, cut them in half or quarters and slice them with the skin still on. Mix the sugar with about 50ml of water and put it with the apples in a pan. Stew until soft.

The Crumble

• 175g Plain Flour
• 100g Brown Sugar
• 125g Butter
• 100g Oats
• ½ teaspoon Cinnamon

Put the oats into a food processor and lacerate them into small pieces. Then dump in the rest of the ingredients and process until it is well mixed.

Put the stewed apples into a baking dish. There was some liquid left over from the stewing, I did not drain it.

Then sprinkle the crumble over the top. Do not pack it down, you want it light and crumbly.

I baked it for about 50 minutes, it was OK but that was probably too long. Next time I’ll try about 30 minutes.

Serve with whipped cream or ice cream. You’ll get about 12 serves from these quantities.

Its nice to know that while I was obsessing over my circuit board, the kids were busy making stuff too. A wonderful Mudistrone Soup!

They are so proud of it.

Now that my pan is ready, it is time to do this. First I needed a board. I got one of my designs prototyped by Batch PCB who are cheap and did a good job but I had to wait about six weeks which is OK for hobbyists but I wouldn’t want to be in a hurry.

This solder paste stuff is pretty toxic. Perhaps I’m going overboard here but I thought some rubber gloves would be a good idea.


To apply the paste, I just squirted it on the board. It kinda went everywhere at first until I got the hang of it. Next time I’ll get a smaller tube and perhaps a smaller nozzle. I fixed it up as best I could using a toothpick and cotton tips. It took quite a lot longer and was much more messy than I anticipated.


Next comes the pick-and-place. I got most of my parts from Digi-key who send them out as “Cut tape” which is pretty convenient, you just peel the backing off the tape until you get the quantity of parts you need and the rest are left still attached to the tape so you don’t lose them in the carpet. I positioned the parts with tweezers since most of them are incredibly teeny.

My board includes both surface-mount and through-hole components. I just placed the SMT stuff at this stage because I need the back of the board to be flat for heat transfer.

Now for the fun bit. I put the loaded board onto the pan cold. Then I increased temperature to around 100°C. I left it at that heat for a minute to get everything nice and warm. Then I cranked up the heat to maximum (in my case, 175°) until the solder melted. It was magic to watch. Everything just blobbed into place. Even components which were not exactly positioned right pulled themselves into line.

After a slow cool-down over 5 minutes, I examined the board. Everything looks good to my eye except for some pretty major bridging between the pins of my ARM chip. I’ll leave dealing with these to part 3.

In the end though, I’m pretty pleased with the result. Not bad for my first try!

I’ve been dying to have a go at this ever since I read some hobbyist websites on how to do solder reflow at home. I never even thought this was possible to do on a hobbyist budget.

The idea is to use a frying pan or toaster oven to perform solder reflow for SMT circuit boards. I decided to use a skillet thinking that a toaster oven would melt components since it heats both top and bottom.

I managed to find the perfect thing. A pre-owned 9″ electric skillet from the Salvation Army shop for $3.

Believe it or not, this device is not a precision instrument. The temperature dial is simply numbered from 1 to 10. The first thing I need to do is get some idea of what actual temperature this thing gets to.


So I need to do a scientific experiment. Firstly I put some oil in the pan and stuck in a thermometer (the fork is to hold the probe in the oil). Then I turned up the heat slowly making a note of the temperature. Finally I graphed the result. Here are the results in degrees C. That cheap little temperature knob is surprisingly linear.

1. Element not energized
2. 30°
3. 46°
4. 65°
5. 90°
6. 105°
7. 125°
8. 140°
9. >150°
10. >150°

The last two entries I could not measure since the thermometer only went up to 150°C, but by extrapolation I get 155° and 175°. Yes I did this on paper, it is much quicker than using Excel!

I am now ready to use this thing for solder reflow.

On Sundays I usually make pancakes for breakfast with the kids. This week inspired by Dave Spencer’s Be a Breakfast Hero instructable, we took the pancakes to a new level.

At first I found I could make some rough face shapes just by pouring the mixture into the pan but to make the more advanced shapes, I had to make a stiffer mixture and used an icing bag to squeeze it out. Mine aren’t as good as Dave’s.

FYI, my pancake mixture is:

• 1 cup self raising flour
• 2 tablespoons caster sugar
• 1 egg
• 3/4 cup milk
• pinch of salt

Just mix it all up, it’s pretty simple. Even my kids can do it.

Here’s some pictures. You can all laugh at our bed-hair!

Thanks for the inspiration Dave!

I haven’t posted for a while. I’ve been spending less time geeking and more time with my kids. So here’s a kid-related post.

Today we made “Comet Balls”. We saw something similar to these at a school fair and Kai really wanted some. So I got some tennis balls and some long colourful socks to make the tails (I could only get toe-socks. Long story, don’t ask. They do look cute with the little toes on the front though).

Making them couldn’t be simpler. Just shove the tennis ball into the sock and secure it with an elastic band. Kai could do it all by himself.

You can throw them quite well when you hold the tail and twirl them. We played a game where Kai and I would try to throw them into a bucket at a distance of two metres. Here’s some photos:

Here’s another unusual use for a phone camera. It’s a simple test to see if your TV remote control is working.

Since digital cameras are sensitive to infra-red light, you can simply point your remote at the camera and you will see the flashing of the infra-red beam on the phone’s screen, digital technology making the invisible visible!

Guess what I found in the gutter in Erskineville. Yes the gutter. In the rain. I thought “now here’s a challenge!”

After dragging it home and powering it up, I saw that the panel would light up, the buttons seemed to work but there was no sound coming out so I opened it up. It was certainly a mess inside (and out). It was filthy with mud and it looked like some cockroaches had been breeding in it. Fortunately, there was very little corrosion on the circuitry so I felt I had a good chance of getting it going.

First thing I did was to take it completely apart and wash all the plastic parts such as the case, buttons and keys with lots of hot soapy water.

After reassembling it, I had a poke around. By connecting some headphones to a wire and probing around the circuit board, I could work out that the sound was being generated but didn’t make it past the main amplifier chip, an LA4558, it seemed to be blown. I had a look through some parts suppliers catalogues but could not locate a replacement for this chip.

No matter because I had a stereo amplifier module surplus from an old project. I got this amplifier ages ago from WES just down the road at Ashfield for about $12 from memory. It is a 5W RMS per side, class A stereo amp. Total overkill for this job but what the hey. I simply bypassed the blown-up chip and fed the signal through the amp module. It has a little hiss, no doubt due to my sloppy wiring or incorrect impedance matching but is really loud when you crank it up.

I screwed the amplifier module down to the metal keyboard frame which makes a handy-dandy heatsink and it is good to go. Not bad for a couple of hours work, a free Kawai MS710 keyboard/synth! Maybe I could circuit-bend it in the future, we’ll see but for now, it makes a great toy for my kids.

I have been using this infra-red wireless keyboard on my media PC for about a year now. I have always been disappointed with its poor range and short battery life.

So I decided to do something about it.

Instead of expensive AAA batteries, it would definitely last longer on AA cells. Four cells would also supply a higher voltage than three and so give greater output power. First thing to do is void the warranty and take it apart.

Then I simply grabbed a 4xAA battery holder and soldered the wires in place of the existing 3xAAA battery compartment. I loaded up the batteries to see if it would work.

Ah, but it didn’t. The activity LED did not light and after a few seconds I could smell the familiar aroma of burning silicon. After very quickly removing the batteries, I had a closer look to see what was up (apart from the main chip being very hot).

Turns out I had relied on the colour-coding of the wires and connected my positive to the red wire and the negative to the black wire. After all, that is the standard right ?

If I had checked more closely, I would have noticed that whoever assembled this thing had used a red wire for negative and a black wire for positive !

After I stopped swearing, I connected my battery positive to the black wire, and negative to the red wire. My engineer mind was screaming “noooo!” but I did it anyway. After that I tested again and it worked! I was very lucky the chips had not been fried by my earlier mistake.

Finally since the battery holder would not fit inside, I glued it to the underside with some hot glue. After testing I was pleased to note that the range was much increased. I can use it while leaning back on my lounge and I don’t have to carefully aim it anymore. With the larger batteries on the case, it should be quite a while before I need to change them.