Wednesday, 31 August 2011

Assembling The Robotic Arm Day 2

Here we are with Step 13 complete, 4 gearboxes assembled, although the last one (designated M2) only has 3 nuts because someone lost one of them:


Here's the 4 gearboxes.

Step 14 involves assembling the components for the base to which the arm attaches. You then insert Gearbox M5 (the first one I made) into a pre-formed well. Also the connectors for the batteries have been fitted.




In this image the wires have been routed roughly as the instruction manual said. Later I will change the routing of the wire from the far end to give me a little more slack.


Step 15: Add more bits over the top of the gearbox, insert the batteries and re-route the wires.

Wait a minute: did I just seal in a gearbox without using a single one of its nuts? I did, didn't I? That means if I now undo most of what I just did I can pinch a nut from Gearbox M5 and transfer it to Gearbox M2, which will need it. So that is what I did - undo stuff, extract the gearbox, disassemble it, steal a nut, and stick everything back together again, to arrive back at this point.

At which point, as I inserted my scavenged nut into Gearbox M2 (amazingly it went in correctly at the first attempt) I realised I'd just been a bit silly - why hadn't I scavenged all of the nuts instead of just one? Well, I'm not undoing everything again, I'm just not.


Step 16: mount the turntable that will allow the robotic arm to rotate, and relocate the battery terminal cable.


Step 17: secure Gearbox M4 to the turntable cap (using the troublesome nuts) and fit the assembly to the turntable.

Now it's beginning to look like something, and my cache of plastic parts and tiny bolts and screws has diminished. The next step will be to assemble the lower part of the arm, using up the 2 remaining gearboxes (the last gearbox, M1, is created as part of the gripper assembly).

Monday, 29 August 2011

Tragic House Fire

Last Wednesday in Queensland a house burnt down in the middle of the night, incinerating 1 man and 10 women and children. There have been lots of questions about the event and a fair bit of wild and uninformed speculation about causes and behaviours. I just want to focus on one thing:


Yepsters, the smoke detector. From the stories told by two of the 3 survivors, if they had a smoke detector in the house, it didn't go off. Which is a great pity, because if there had been a working smoke detector in the house, it is very likely all 11 dead would be alive today.

Smoke detectors are mandatory in multi-unit buildings, and in all residential properties offered to let, at least here in the ACT. They might even be mandatory in new houses, I don't know. However, I do know that you can't be required to fit one to an existing house, you can only be encouraged to do so.

Well, let me help with the encouragement. If you live in a house by yourself, you can do what you like with respect to smoke detectors, right? If the bloody thing keeps going off because of the hot oil you use to make your chippies, you can just disable it, right?

Well, no. It's only your sole risk up to a point. If you leave the chip oil heating and go to bed, you may not wake up until the house is well alight, at which point all you can do is escape. Lack of a smoke detector has allowed what might have been an extinguishable fire to turn into a conflagration. And if that conflagration sets fire to the place next door, as it very well might before the fire appliances show up, then the insurers of the property next door are going to come gunning for you. And you've probably voided your own insurance policy, if you have one.

And if you're not living alone, it's even worse. If it's your house you have a duty of care to others who may occupy it, no matter what your belief about the evilness or otherwise of smoke detectors. If you don't have a working smoke detector, you've got exactly zero defence to a manslaughter charge in the event that your house burns down, killing some of the occupants.

Experience in the USA has shown that too many people do have smoke detectors but never test to see if they are working. As a result, too often the fire brigade is called to a conflagration rather than a blaze in a corner, and far too often lives are lost.

The solution is simple: get a smoke detector, fit it where the manufacturer suggests, test it every 6 months and, every second test, replace the battery. Ooooh, horrible environmental catastrophes will follow if we all use that many 9v batteries and throw them away. Bollocks. A house fire releases enough poisonous stuff from all the plastic alone to pollute a suburb for weeks.

Sunday, 28 August 2011

Man Says Aaaargh

Did I mention that the nuts are tiny? The nuts are very very small. And difficult to insert. Here's an image:


The width across from vertex to vertex is about 4.5mm and the diameter of the hole is 2.6mm. You can see how tiny the nut is compared to the small needle nosed pliers.

On Friday I started assembling the second last gearbox. After six attempts to insert the first nut I might have become a little frustrated, I don't say I didn't. So as I was withdrawing the incorrectly aligned nut for the sixth time I might have been gripping the pliers with a little more than usual force. Whereupon the nut shot out of the pliers, went clunk against something wooden nearby and vanished.

So I got down on my hands and knees and searched for it, first by eye and then with the aid of a LED torch. No sign of it. Feeling around didn't reveal it either. So I did a police-type search by sectors. No nut. So I did a search through the bag of bits, hoping against hope that the supplier had given me an extra nut. Nope. Some bean counter in the Taiwanese company that made this robotic arm had decided that they could save a billionth of a cent by only supplying the exact number of tiny easy-to-lose parts that the assembly required, so that's what they had done.

I did notice that I only had 3 washers, when I thought I needed 4. I briefly toyed with the idea of making a warranty claim for a missing nut and washer, but decided that was silly, so on Saturday morning I went to the electronics store to see if I could get replacements.

I discovered that the smallest nut I could get was for an M3 bolt - M stands for metric and 3 stands for 3mm. I knew this wasn't going to work, since the missing nut suits a 2.6mm bolt, but I bought some M3 bolts, washers and nuts anyway:




Take my word for it, they're small. Also, sadly, the M3 nut will not fit into the pocket in the gearbox housing because it is both too wide and too thick. So I'm going to have to bodge something up with an M3 machine screw (which bites into the plastic) and some epoxy adhesive.

What was that proverbial rhyme about the " ... want of a nail" that leads to the kingdom being lost? Well, I'm going to nip this in the bud, and glue my way out of trouble.

Thursday, 25 August 2011

Assembling The Robotic Arm Day 1

Here are some images showing how it is coming together. To give a senses of scale, the grid on the cutting mat is 10mm square.


Step 1: Gather together the required bits.






Step 2: Separate the gearbox casings from the runner, and file off the residual lumps.




Step 3: Insert 4 tiny nuts into their housings, making sure that the vertices are top and bottom, not the edges. This was a horrible job; most of the time the very act of inserting the tiny nut rotated it as it was held in the jaws of the needle nosed pliers, resulting in the edge being on top. I had to make many attempts with each nut before I finally got them all correct.

Step 4: Insert the main gearbox cog in the big hole and insert the shafts.


Step 5: Insert the remaining gearbox cogs and make sure it all works before inserting the motor.

Step 6: Find the correct motor (you can only tell by the colour of their wires).


Step 7: Insert the motor, being ludicrously careful not to dislodge any of the 4 tiny nuts, and draw the power cables through an outlet at the rear of the housing.


Step 8: Attach the other half of the housing, and heave a sigh of relief because the tiny nuts can't go for a walk any more.


Step 9: Flip the motor and get ready to insert 3 very small self-tapping screws.





Step 10: Tighten the self-tapping screws to lock it all together. Easier said than done. Because the screws are very small you have to use a very small screwdriver, which means you don't get much leverage. Drive the screws in turn about 4 turns. Back out the screws a couple of turns and drive again for 4 turns. And so on until the screws are snug and won't go any further. I nearly weakened and got out the power drill, but using a power screwdriver on a self-tapping screw isn't the right thing to do.

But after 30 minutes of fiddly work, the first gearbox is complete.


Step 11: Make another one, exactly the same. Another 30 minutes. At which point the hand operating the screwdriver started to tremble, so I stopped for the day. Steps 12 and 13 involve making another two gearboxes exactly the same except for the colour of the wires.

By my count I've used 34 of the total 187 parts, so even when all 4 of these gearboxes are complete, there will still be nearly 120 parts to be fitted. Another few days to go yet.

Sunday, 21 August 2011

The House Temperature Done Better

Friday night was going to be 3 deg. C overnight. I did what I usually do and left the curtains and blinds open, and, on Saturday morning, I got up at 6:30am just as the heater started up and snapped a pic of the thermometer under my computer monitor. I might have snapped just before the auto-focus had finished, which would be why it is slightly blurry.


I'm going to call that 13.5 deg. C, so the house shed 8.5 deg. C in 8.5 hours, or a neat 1 deg. C per hour.

Saturday night was going to be be 3 deg. C overnight too. This time I spent 15 minutes before I went to bed closing all the curtains and blinds, and shutting the doors to the bathrooms (because these have plastic skylights) and the laundry. And at 6:30am on Sunday I got up and snapped a pic of the thermometer, this time waiting until the auto-focus had finished.


I am going to call that 14.75 deg. C, so the house shed 7.25 deg. C in 8.5 hours, say 0.85 deg. C per hour. So we've achieved a 15% reduction in the rate of heat loss by sealing the place up, which sounds impressive, but in reality it isn't - I mean, whether it is 14 deg. C or 15 deg. C when you get up in the morning probably isn't something you can really detect. All you know is that it isn't very warm in either case.

You'd get a much better result if you did at least one, and preferably all three, of the following:

  • Bump up the roof insulation to the maximum possible
  • Insulate the exterior walls
  • Replace all the windows with thermally broken double-glazing systems
Since I don't own the place none of that is going to happen, so I'll continue to leave the blinds open so I can see the stars at night. I seriously doubt that launching the heating from 15 deg. C instead of 14 deg. C in the morning translates to a 15% saving in my gas bill - more like 1.5%, or something like $30.00 pa.

Thursday, 18 August 2011

I'm So Excited

I probably need something to calm me down because I've got some fiddly work to do. Look what arrived by courier yesterday afternoon:


Inside the box are about 200 parts - some plastic on runners, like an Airfix kit, and some in plastic bags, like motors or tiny screws and washers. Sort of like a cross between an Airfix kit and an electronics kit. When complete it has an extended reach of about 300mm and it can lift 100g. If I manage to complete it correctly, of course. I shall need some tools:


When it's finished and I've figured out how to control it, I'm going to hook it up to the laptop so I can program it. Since it can only lift 100g it's not going to be fetching me another beer any time soon, even if it had wheels, which it doesn't. In fact, even if I had 6 of these robotic arms working in synchrony, they'd be at their lifting limit with a full stubby of Boag's Draught. Never mind, this gadget is a training toy.

Now where did I put those complicated assembly instructions?

Wednesday, 17 August 2011

Ooop ...






Well, that wasn't what I expected. Sealed up the house as tight as I could, and when the heating came on it was 15 deg. C under the computer monitor - 2 deg. C cooler than yesterday.

There are so many flaws in my experimental method that I think I'll ignore yesterday's result and start with this one instead. 7 deg. C drop in the 8 hours between 10:00pm and 6:00am with the house sealed up tight and an overnight low of 4 deg. C. It's going to be about the same overnight over the weekend, so I'll repeat the experiment then.

The house was noticeably warmer when I got up this morning, but it feels horrible having all the curtains closed. I'd be interested to find out what fitting double glazed windows would cost. I'm certain the landlord wouldn't be willing to spend the money, but I'm curious.

Tuesday, 16 August 2011

What Happened To The Heating?


This is Canberra in winter, of course I've got central heating. Since I'm home for at least part of the day every day between 9:00am and 5:00pm I leave it running all day. This turns out to cost an extra $100 per year compared to switching it off at 9:00am and turning it back on at 5:00pm. This is because it takes nearly as much energy to reheat a cold house as it does to just keep it constantly warm in the first place.

The heating comes on at 7:00am and goes off at 10:00pm. every day, and because the system is ducted gas through the roof space blowing warm air down, I have the thermostat set to 23 deg. C. When the place is warmed up this delivers a temperature gradient of 20 deg. C at the floor, 23 deg. C at standing head height (which is where the thermostat is mounted) and about 25 deg. C at the ceiling. So it's about 22 deg. C at seated head height, which is comfortable.

Except this morning the heater didn't start. Usually I wake around 6:30am and so I get to hear the 'whump' of the gas heater starting up. The fan starts spinning and you hear the air moving at 7:00am, the scheduled start time. This morning - nothing. So I went and inspected the thermostat to find that it had reset itself to Saturday 4:00am. Since no other wired devices with clocks had been affected, I'm guessing it is more likely that the thermostat is on the way out.

But it gave me a chance to assess the performance of the house overnight, which I hadn't thought to do before. Heating went off at 10:00pm yesterday as far as I can remember, so the house had been cooling for 9 hours. The thermometer under my computer monitor normally reads 22 deg. C when the temperature in the house is stable. That's it in the picture above, reading 17 deg. C at 7:30am.

It was 4 deg. C overnight, quite mild for Canberra in August. So the house shed 5 deg. C over 9 hours when the inside-outside temperature differential was 18 degrees i.e. 0.5 degrees per hour. Now I always leave the bedroom blinds and curtains open because I like the light. I'm going to try an experiment and see if I can improve the performance of the house just by closing the blinds. I know everybody seems to think it makes lots of difference, but I'm interested in whether it makes a noticeable difference.

While I can't control the outside temperature, it's going to be 3 deg. C tonight, so that's near enough.

Sunday, 14 August 2011

The New(er) Blue Z

I can take better photos than this, really I can. Some time in the next month or so I will pass the 10,000km mark on the New(er) Blue Z. This photo was taken on a recent trip down the South Coast of New South Wales. That trip showed me the inadequacies of my luggage arrangements. The magnetic tank bag doesn't hold as much as you think it should, and it creates uncomfortable turbulence, while putting everything that didn't fit into the tank bag into a backpack just left me with tired shoulders.

Removable panniers and a pillion pad base for my tank bag seems like a better solution. I can feel the urge to do some interweb shopping coming on.

Thursday, 11 August 2011

Missing Table Of Australia's Wars


Colonial Period 1788 – 1901 Colonial Era
Sudan 1885 Colonial Era
Boer War 1899 – 1902 Colonial Era
Boxer Rebellion 1900 – 1901 Colonial Era
First World War 1914 – 1918 Just
Second World War 1939 – 1945 Just
Korean War 1950 – 1953 Just
Malayan Emergency 1950 – 1960 Unclear
Indonesian Confrontation 1963 – 1966 Just
Vietnam War 1962 – 1975 Unjust
First Gulf War 1990 – 1991 Just
War In Iraq 2003 – 2010 Unjust
War In Afghanistan 2001 – Present Unclear

Australia's Wars


I am troubled by dichotomies in how I think about Australia's wars. Back in the sixties and seventies I objected to Australia's involvement in Vietnam. I wasn't very passionate about it, and I never marched in a Moratorium, but I held the view that we shouldn't be involved. To my mind the Vietnamese had been fighting a war of colonial independence, and doing pretty well against the French, and the Americans had no business interfering. And we had no business helping the Americans.

My view today is largely the same, except a little more nuanced.

At the same time I drew a distinction between the war itself and the Australian troops doing the fighting. That is, the war was objectionable, but the soldiers were not. In fact, I objected loudly to the way Australian troops were often reviled when they returned from Vietnam (this happened on more than one occasion). I discovered that very few people shared my position: they either supported the war, and therefore the soldiers, or they objected to the war, including the soldiers.

During the sixties and seventies my father subscribed to the science fiction magazine 'Analog'. Each month there was an opinionated and very provocative editorial by the magazine's editor, John W Campbell. The subjects were most often political, and he delighted in making people think. As an example of his provocative style: he argued that mechanisation would have eliminated slavery in the end anyway, and thus if America had just put up with it for another few years the Civil War never would have happened.

Some time in the late 1960's, perhaps some time in 1967, Campbell wrote an editorial about the Vietnam war. He was ambivalent about America's involvement but he had no doubt at all that the American way of fighting the war was completely wrong. To make his case he used the Australian troops in Phuoc Tuy province, describing them as the best counter-insurgency troops in the world. They had pacified the province without whole-scale napalming of villages and had demonstrated (at Long Tan) that they could take care of themselves when vastly outnumbered in a big firefight. Most important, in Campbell's view, was that the Australian troops had succeeded in obtaining the amity of the villagers, which made it much harder for the Viet Cong to get help and support.

My chest swelled with pride when I read that. Little Australia, “ … the best counter-insurgency troops in the world.” Mind you, I would have been about 15 then; an impressionable age. And whether Campbell was qualified to judge I wouldn't know.

But this set me thinking: if it is possible for soldiers to act with gallantry and do their job well in an unjust war, how many of Australia's conflicts have been unjust? I obtained the following list of Australia's wars from the Australian War Memorial web site, deleted the police actions and added Iraq and Afghanistan. My take on each conflict is below the list.

Now by 'Just War' I mean a war in which Australia itself or its Territories or interests are under attack by a foreign power, or a war in which Australia has an agreement to come to the aid of an ally. I'm sure there are plenty of people who would argue that there is no such thing as a 'Just War', and I've had conversations with people who have asserted exactly that, but I'm a realist – if the bullies are picking on you or your mates, then you have the right to stand up to them.

We'll ignore conflicts of the Colonial Era because the decision to involve Australian troops was made in London, not Australia.

First World War

Entire books have been written about the causes of the First World War. In a nutshell: a Serbian partisan assassinates Arch Duke Franz Ferdinand of Austria-Hungary. Austria-Hungary tells Serbia to say sorry, big time. Russia tells Austria-Hungary to stop picking on poor little Serbia, or else. Germany says if Russia interferes, Germany will get involved. The United Kingdom says if Germany threatens Russia or France, the United Kingdom will come out swinging. The Germans respond by invading France via Belgium, and everybody gets involved.

Australia, although now a sovereign nation, is nevertheless a member of the British Empire and has a duty to assist.

Call: Just War

Second World War

This one's not so confusing. Germany invades Poland; Japan attacks Pearl Harbour. In the former case Australia is still a member of the British Empire and has a duty to assist; in the latter Japan brings war to Australia's doorstep and threatens to invade.

Call: Just War

Korean War

I'm going with a technicality here: after North Korea invades the South, the United Nations Security Council calls on member states to contribute troops to push the North Koreans back. Whether Korea should have ever been partitioned in the first place is another matter entirely, but the North Koreans started the war and the United Nations sanctioned Australia's involvement.

Call: Just War

Malayan Emergency

Malaya is a part of the British Commonwealth and is facing an insurgency by ethnic Chinese who are cheesed off that all the things they were promised would happen after decolonisation have not occurred. The UK calls for Commonwealth support to fight the insurgency, particularly from Australia because of our proximity. Whether Australia had an obligation to get involved in someone else's civil war is moot.

Call: Unclear

Indonesian Confrontation

Indonesia invades Malaysia. Australia has a mutual defence treaty with Malaysia. Malaysia asks for help and Australia responds.

Call: Just War

Vietnam War

I suppose someone will argue that Australia was obliged to support the USA in Vietnam because of the terms of the ANZUS Treaty, but in fact ANZUS only comes into force when any one of the three nations is attacked. It is hard to define VC/NVA attacks on South Vietnamese or US forces in Vietnam as the United States being under attack. As I have said before, the USA had no business being in Vietnam, and Australia should not have got involved.

Call: Unjust War

First Gulf War

Pretty clear cut. Iraq invades Kuwait, a sovereign nation, which calls on the UN for help. The UN Security Council calls on member states to contribute troops to a force to kick the Iraqis out. Australia contributes naval assets, and lots of other countries contribute ground forces. The Australian involvement is sanctioned by the UN Security Council.

Call: Just War

War In Iraq

Pretty clear cut in the opposite direction. Just because some Yemeni born, Saudi trained terrorist in Afghanistan launches passenger jets at buildings in the USA, it's OK to invade Iraq? Weapons of Mass Destruction my arse: even North Korea was reluctant to supply nukes to Iraq. And take a look at the list of nation states that haven't been invaded despite the fact that they are not permanent members of the UN Security Council, and they really do have nukes: North Korea, India, Pakistan, Iran and Israel. And Syria would be there too if the Israelis hadn't bombed their facility.

Call: Unjust War

War In Afghanistan

The pretext for the war in Afghanistan is that the Taliban gave shelter and assistance to Banana bin Laden. Nobody is game to do what Timur the Lame (Tamerlane) did when the Afghans gave him trouble, and just kill everybody. If genocide isn't an option, it's difficult to see what NATO are doing there.

Call: Too soon to tell but it's got a smell of napalm about it.

So there we have it – do two huge mistakes (Vietnam and Iraq) obliterate the good that was done in the other conflicts? Sadly, in my view, yes. It doesn't pay to look too closely at some of the conflicts I am calling as Just Wars, and sometimes the good that was done was negated within a decade. Australia lost in excess of 1% of its entire population in the First World War in 3 years of fighting; if we had experienced in excess of 200,000 Australian deaths in Afghanistan, we wouldn't be there.

But in every one of those conflicts a great many Australian soldiers did their duty proudly and often with great courage. Should they cop the blame because the Australian government that sent them to war made a mistake? Should they cop the blame because the political leaders and generals made mistakes in strategy (think Gallipoli)? Absolutely not.

Anzac Day celebrates the lives, and, all too often, the deaths in combat, of Australian soldiers and non-combatants. It is an event of annual remembrance and reflection. We should all ensure that it does not become captured by the jingoistic war mongers who celebrate war and always reach first for the military solution.