Neither rhyme nor reason

If you are a news junkie like myself, you may have noticed that ABC News provides Google-like references to purportedly relevant news articles to the one being viewed, down the right side of the page. I have noticed however that their relevance engine clearly has some issues. The story this morning was titled “Sydney welcomes second cruising Queen” which was about the historic event tonight as two large ocean liners, Queen Victoria and Queen Elizabeth II will pass each other on Sydney Harbour. A had good chuckle when I read that the supposedly related articles were:-

• Council welcomes second airline - 21 Mar 2003 (Planes not ships - and hopefully not passing each other at 100m distance!)
• PM welcomes Swedish royals - 7 Nov 2005 (Some real royals)
• India cruising in Hobart - 14 Jan 2004 ( A royal game maybe, but the Indian cricket side is cruising along here)
• Australia cruising to huge total - 7 Oct 2005 (This time it is the Aussie cricketers going for spin)
• Melbourne welcomes Prince Edward - 12 Mar 2006 - (Another real royal)

Not a ship to be seen. Oh well Aunty ABC, maybe you should have a chat to Google!

After attending LCA2007 (last year) and catching Tim Ansell’s show and tell on some PIC microcontroller based projects, I got inspired. He mentioned that Microchip offer free samples of their PIC chips, so I managed to get my order in for a small variety (a 12F629, 16F88, 16F688 and a 18F2550). All of these have a different target application (small and simple (8 pins), to mixed salad (18 pins, with 16 I/O including analogs and USART) and up to USB capability. Anyway I have had the chips for a while and I was researching programmers (to burn your program on to the chip). I didn’t want to spend much money, and was going to build my own, but eventually I got lucky and got a PICkit2 clone from Sure Electronics on eBay. I also board a breadboard and to get me going on a project some 8×8 LED display modules.

Anyway I have been having quite a bit of fun. I managed to build up a simple display driver circuit using an idea I thought of, but it seems others have as well, using shift registers to latch the row and column data for the display. This also minimises the pins required from the microcontroller. I also got digital and analog inputs working, with a potentiometer able to adjust the rate my display changes. I am using the 16F88 PIC along with 74HC595 shift registers.

Eventually I wouldn’t mind build a message display using the 8×8s and a USB connected PIC. The “real” projects I would like to work on would be some simple sensors around energy and water - but don’t hold your breath. The thing I found amazing is that I have picked up, and even enjoyed , programming at assembly level again. PICs are basically RISC processors, so there is not many instructions to learn (less than 40 for for PIC16). Working at that level you have to think a lot about timing and conserving space, how best to get input and provide output (with limited resources). While my current programs are just endless loops, grabbing inputs and stuffing output pins (and mind you this is probably what you want a hard real time system to do), the next thing I want to learn is to set up timers, interrupt service routines (watch for timeouts and/or input changes) and so on.

Where microcontrollers excel over discrete logic is that provided you bring inputs and outputs together at the right level, you have a lot of opportunity to tweak the processing of inputs late in the design process. This has a lot of advantages to somewhat impassioned and impatient creative types like me.

Any way I have attached a photo of my breadboard, and a dump of my (very messy) code.

Well it’s the conclusion of Day 1 of linux.conf.au. (The official conf doesn’t start till Wednesday - but the mini-confs are just as much value). I hovered between the security mini-conf and a few others. Michael Davies gave a quite informative talk on signing code fragments before they end up in distro repos. Enno Davids talk on self-defending networks was pretty neat. He had some good insight into the issues surroung DDoS attacks - particular he propogates some useful ideas that might make use of ICMP to signal pwned bot hosts operating systems to back off for a little while. (Of course this assumes that the essential integrity of the bot herd’s host operating system is not compromised . There was a very neat lighting talk from a real white-hat hacker (who seems fairly grey in a lot of his outlook) called Metlstorm. He is a Kiwi his alterego is Adam Boileau. Pretty smart guy working on a lot of projects. ssh-jack allows you to eavesdrop on a ssh session on your host, without letting the user being aware - purportedly to keep an eye on the bad guys.

We also had a pretty long-winded GPG key signing party. Unfortunately I feel pretty deflated after finding about I got duped by one of the attendees with dubious ID - http://madduck.net/blog/2008.01.28:on-the-point-of-keysigning/ . What I am more dissapointed in is that the keysigning herd didn’t protect itself, instead letting everyman fend for themselves. Clearly in my mind a true Web of Trust ought to protect itself when an attack on it’s integrity is observed. I can only blame myself for accepting Martin’s ID (and in hindsight I can remeber even what it looked like), but I do feel there should be an obligation to protect each other.

Just before the last service I had arranged for our 2001 Holden Zafira, I noticed that the odometer had gone black. While it looked like some sort of LED dot matrix display, after some investigation with a torch (and comparing the other displays) it seemed to be some sort of backlit LCD panel. I asked for the people doing the service to have a look at it for me. They rang after they had done the normal service and told me the bulb could be replaced, and the bulb was only a few dollars, but it would cost me $150 to do the job. This was because the whole dashboard would need to be removed just to get to the bulb. So I decided there and then, I would get them to supply the bulb and have a go myself.

Well, after a few false starts (mainly around getting the radio out, but also I struggled to one screw that preventing me removing the dash), I managed to fix this a few weekends ago. It was quite rewarding to do this, as these days I tend to get my cars fully serviced at the dealer service centres. I also thought that there was some really nice engineering in how all the modules were designed to fit together.

Anyway if you have a Zafira, which is basically a pregnant Astra, you might find the photo diary I recorded here useful. (BTW for those that are interested the Holden Zafira is assembled in Thailand, but it is basically the same design as the GM Vauxhall Opel that is built in Belgium)

My youngest son has for a long time had a fascination with all things to do with combat. Most of his make-believe time is concerned with sword-wielding warriors or gun-toting aliens. A few times we supplied him with plastic armaments that are available in two dollar shops and even your quality toy store. However at hour place, these never last more than a few tournaments. Also, swords seem to be about 1/4 scale - not much fun for real play fighting. So a few birthdays ago under cover of darkness, I spent a few evenings putting together a sword and shield. It certainly has stood up to the rigours of combat , as well as impressing a few other kids and their dads. After a bit of a lull on the battlefront, the son has renewed interest of late - however having only one sword has meant his combatants have been at a disadvantage, often having to use regular sticks or cardboard rolls for their weapon. Also, because these inferior weapons don’t have guard or hilt, the other party often gets a good whack on their hand - mum was the latest casualty. I succumbed to the pressure this weekend, and below is a bit of a photo log of the construction of a second sword.

Basically, it is constructed from standard plywood, 5 ply 12mm for the sword base, and some 3 ply 7mm to add some strength and thickness for the hilt and handle. You will need some construction glue to laminate the pieces together. Tools are just a jigsaw, an angle grinder with a flap wheel (to tidy up the edges) and a rotary tool with grinding wheel (to do finer smoothing) and a possibly a ball cutter to make the fullers (or “blood grooves”).

Any way, basically this might be something to make for your kids for Christmas - hopefully it might even last a little while and become a family heirloom!

I made a template in Inkscape and traced this onto the 5 ply.

Make another two hilts from the 3 ply and glue, sandwich and clamp these. You can also screw them - I used chipboard screws with a square drive for good effect.

You will want to use grinder with a flap wheel and a rotary tool for finishing it off

After adding the blood groove and sanding it smooth all over it is ready for painting

The shield is also made from 3 ply. I cut up an old belt and used brass screws and nuts and a large washer to make the handles.

I got a modest refund from my tax return for 2005/6. I have been wanting a mountain bike for a little while so I had a bit of a look around for the last few weeks. I also wanted to get one for the lovely mrs. You can certainly get a nice bit of machinery, and you can also spend many thousands on it. Anyway rather than spend crazy amounts of money and not being sure that I will like it (and be serious enough about it), I settled on basically the best (read most expensive) bike that BigW sell. Anyway for the mammoth total of $298, I ended up with a quite nice bike. It is a softtail (I only learnt that term during my recent research - it means it has rear suspension), and of course has front fork shocks. Alloy frame, and 21 speed Shimano controlled by grip-shift. What I thought was pretty good was this it has disc brakes as well as deep rims. The brakes look cool, but I think that will especially well in the wet, as the brake system is well away from the tyres.

I have already tricked it up a little, I bought LED lights as well (it might mean that I can do some exercise during the week), as well as longer seat post (being 183cm meant that the existing post and frame forced my legs to be a little to bent at the longest stretch.)

(Oh, and so as not seem too self-indulgent I bought my wife, a ladies’ model!)

Apart from a few laps around the village, I hadn’t really put the bike to any test. So I decided to go exploring around some of our local firetrails. And have been have a great time. I’ll publish some GPS tracks very soon.

Very rapidly we seem to be approaching an age of artificial light no longer being the result running current through filaments of wire. While fluorescent lighting is pretty old, we are finding it being condensed into the compact fluorescent form which is able to replace the regular incandescents. What hasn’t really taken off yet though is a much more efficient lighting method - Light Emitting Diodes. While LEDs are also quite old (we just watched an early 70’s Columbo episode where the murderer ran an electronics company and he was proudly showing off his red LED digital watch he had designed), only in probably the last 3 or 4 years have the ultra-bright white LEDs been around. These have found much favour with the outdoor types for use in long lasting torches and the like. We even have now almost ubiquitous solar-powered garden light. I bought my wife a LED equipped book light recently as well which is pretty good use of this technology.

I have been keeping an eye out for LEDs for general architectural use for a little while now. One problem is that the colour temperature has tended to be very blue and narrow - this meant that illuminated objects didn’t seem to be in full colour. Also you really did need a lot LEDs to get good brightness. Finally they have been pretty costly. Anyway, I visited my local electronics store the other day and spied some 12V MR16 halogen replacements. Unfortunately at $40 each (and the sales guy not all that convinced a permanent store display was worthwhile), I decided to scour Ebay instead . Sure enough, an enterprising Chinese company was able to sell me 3 LED spotlights posted to me for just over $40. We got these last week and installed them in one of our living room fittings. They look pretty cool (warm actually - the colour temperature is definitely redder than the halogen and maybe even a tunsten filament incandescent). They replaced 20W halogens - I would say their brightness is about the same. They certainly are cool to touch, I should measure their current use to find how efficient they are. Unfortunately though they don’t respond to dimmers well. Rather than getting less bright, when I turn down the dimmer they start to falter, flash and then just go out. I guess being a first generation of this type of thing, I am presuming that are using a fairly simple regulator. The dimmer would be a duty cycle chopper but I am not sure whether the 12V halogen supply is a simple transformer or a switch-mode supply. Either way, these can dim and control a halogen bulb properly. I would have thought that a circuit to sense the input supply (whether chopped or simply lower voltage) and could drive the LEDs appropriately shouldn’t be all that hard (though it needs to remain efficient of course).

The other interesting thing is that all the LED lamps I have seen to date (including the ones I bought) use regular discrete LEDs in large arrays. I am surprised that no one has developed some sort of array substrate that contains lots of LEDs. This way a direct area light could be created that could be molded in all sorts of shapes. Even one that resembled a regular light bulb - but with lots of light spots around it. I expect that there will be heaps of innovation along this front in the next few years - particular with a drive to reduce our energy footprint. (And of course the other things is that LEDs themselves should have a 100 000 hour life - which means these new LED bulbs I bought might simply become quaint and old-fashioned before they actually burnout!)

As soon as people found out I had an OLPC XO it seemed I became flavour of the month. - they all wanted to see it. My first engagement was the monthly talk at SLUG. I prepared 15 slides for a presentation that introduced the mission of the project, a few photos from a pilot in Nigeria, and a walkthrough of the hardware and software components. I then did a demo using the Build 385 qemu image as well as the XO itself. Anyway I got a lot of interaction, and lots of people wanting to have a play. Most were pretty supportive of the project. One though didn’t think they would last very long and would soon be wrecked by the kids not knowing the value of that. While I didn’t think that rang true, I didn’t have much to back my defence at the time.

That changed today however. A while ago I volunteered to spend some time on the Linux Australia stand at CeBIT. Anyway, as I now had an XO I was encouraged to bring that along. Here it also got a lot of interest. Quite a few people had heard of the project, but there still was a lot that hadn’t. What was really funny was that every second person wanted to know what happened the wind-up handle! (Which of course, disappeared from the design when it was found that it put too much stress on the unit, and also was difficult for young kids to use). I
managed to pretty well talk myself hoarse - I certainly enjoyed the spruiking.

What also was very encouraging was talking to a Nigerian fellow who currently lives in New Zealand. I queried him about the concept that the kids would wreck the machines. He said it would be absolutely the opposite! These kids would guard their machines with the life - particular if they have little else of value. He spoke of seeing kids that had exercise books that they would write on school with a pencil. Then, when the term or subject was finished they would diligently erase their writing eventually resulting in books almost worn thin. So I really do think in general they would be well looked after.

My 3rd engagement should be a little more laid back — to the smaller gathering at this month’s SCLUG meeting.

I received an email just before Easter that was a bit of a surprise. It was from laptop.org asking for my postal address. It said that they wanted to send me an XO! I’d nearly forgotten about the submission I wrote during LCA to the OLPC developers list. Jim Gettys encouraged those that thought they might be able to contribute practically to the project to write a submission. Three were given away at the conference.

Anyway, I feel pretty privileged to have received one about 2 weeks ago. Jeremy certainly has been pretty enthusiastic about it. It might even inspire to him to learn Python - most of the applications (called “activities” on the OLPC platform) are written in Python - at least as the glue to talk between the user interface and any hard-core logic.

There has certainly been a lot of thought put into the OLPC to bring it this far. As almost everyone has said, the screen is quite brilliant. Being LED backlit for darker rooms, and being able also be used without backlight in bright sunlight is, well brilliant. Having a built-in camera is quite important as well. They have a dual mode touchpad/graphics tablet that allows normal mouse cursor movement to be controlled with the finger, but also allows absolute drawing and tracing using a stylus (you have to fashion your own) on a larger tablet.

I have spent a fair bit of time understanding how the software is put together. While it is basically built from Fedora, I understand that a lot of things have been done to conserve power. It performs admirably well for having a 433MHz CPU, 128MB RAM and no swap. I have learned a little about how Sugar activities are packaged into bundles. I even loaded up a HelloWorld.Activity. The production XOs look like they are going to have the faster and less battery-hungry Geode LX (rather than the GX) as well as double the RAM.

I’m very keen to my family contribute to how it can be used to foster music amongst the kids that will use OLPC. Tamtam is a great application already - I would like to see how it can be better used for teaching music fundamentals. (Of which I only know a little - hence my very musical family are going to have to help me out.)

A colleague of mine who has quite a few OLPCs, mainly for testing the wireless stuff out, told of the absolutely clever analog input port the OLPC has. Not content with a regular AC microphone input, it can be configured in two other modes. One is a straight DC input that can measure between 0 and 3VDC. I immediately thought of kids in Africa being able to hack electronics together from old radios and the like and using the OLPC as a simple oscilloscope or voltmeter. The other analog input puts 2.5V and allows you to measure across this. This means a simple potentiometer can be read. Great for all sorts of science experiments, but also a good way of providing another interface to control the Tamtam musical instruments.

Unfortunately I have been all too busy to do much with it. Anyway it looks like I’m going to have to be a bit of an unofficial local ambassador for the project. As soon as I mentioned to SCLUG that I had one, they wanted me to speak at the next meeting. And I let it drop to the SLUG president as well, so he has asked me to speak at their next meeting.

Oh, and I am writing this post with my OLPC XO of course!

We have had a pretty good 2 days so far at LCA. As I expected, I flittered between the Virtualisation, Gnome and Debian mini-confs. I learned a lot from Jon Oxer’s talk on Xen Image Manager. Probably most interesting was learning about recent glue tools such as ATA over Ethernet ( a poor man’s iSCSI), drbd ( A Network RAID-1) and Unison (a better rsync). Anyway it certainly has some good ideas for building reasonably sophisticated data centres on a budget.

We also heard a little about the OLPC project from Chris Blizzard’s keynote - and catching up with James Cameron at morning tea meant that we could actually have closeup look at the one he has been testing in the bush.

At lunch I was able take a ride on Geoffrey Bennett’s open source segway clone.

Jono Bacon exemplified the value of open source development, talking about the audio editor Jokosher that spawned as a result of the need to fill a niche for a multi-track editor that mortals could use.

Anyway a pretty good days so far!