About Me

I've been taking things to bits, and making things ever since I can remember, starting with dismantling knackered alarm clocks and watches and helping my dad fix the car. Now I have a well-equipped workshop and have aquired lots of new skills, so I can make better stuff. When they first appeared, I became involved with personal computers, and these and developments in electronics have increased the scope of the things that I can do. Just recently retired, so O yes, now I can make all sorts of stuff.....

Thursday, 25 July 2013

July news

A bit late this month with this update, lots going on as usual.

Last month we had some sad news about Sergei the meerkat. This is a further update from Alexandrei Orlov, Sergei's friend:
"Peeples. Am wanting to thank all who send letter with sorry for Sergei, very kind, but waste of timing. Am also here to tell that I am very angry.  As all know, Sergei found hanging in workshop of Meerkovo Airways and everybody think he too stressed with new job and hang own neck. But when Vassily go to cut body down, he find that it not Sergei at all but just stupid meerkat toy!

Big searching by Meerkovo Security Agency (MSA) have discover many thing:  first, Sergei have pilfer many rouble from accounts over long time using IT skill.  Second, new stewardess Tanya have disappear, and three: new Meerkovo airplane have missing also.  MSA have follow airplane to Moscow airport and are believing that Sergei and Tanya are hide with american spy, Snowdon Edward.

This all very bad. Many rouble is gone, and Sergei having much cheap vodka and all kind of duty-free game with Tanya while I am bite furniture with angriness. MSA is on case, will catch stealing meerkat and bring back, hanging in workshop will not be joke this time."


Brass clock mechanism

This is one of my favourite pieces of silliness ever and I am childishly pleased with it. I have had a gear cutter for my little milling machine for a long time, and finally decided to try it out by making a clock mechanism.  I started by making a mock up, then amended the bits that didn't work properly and produced the final article. The pictures are a bit pants, but give the general idea (the black lump is the stepper motor).

Cutting an alloy gear on the mill
Its a pretty simple gear train, as the clock only has two hands (minutes and hours) and a simple 12 to 1 train between the spindles.  The smaller gears are turned from brass rod, with the bigger ones made from aluminium, and then the teeth are cut using the rotary table stood on its side. I made all the gears with numbers of teeth that can easily be counted in whole degrees as I don't have a dividing head. The smaller gears were cut from one solid rod and then parted off on the lathe. Each set of gears was then mounted on to a brass spindle and a silver steel shaft pressed into each one.

The front and back plates are made from 2mm thick brass, with the gear spindle holes carefully drilled to the correct centre distance on the mill using the rotary table to get the correct angles between them. The original prototype was marked out with dividers and drilled from centre-punched marks, but the spacing was not accurate enough and the gears didn't mesh properly.

Stepper motor and controller
The clock is driven by a small stepper motor - less than two quid each from my friends in China - and the drive from this is geared up 9 to 1 so that a large number of motor steps provides a small movement at the minute hand.  I've had it running off the Raspberry Pi and it chunters away happily.

The plan is to drive the motor from an Arduino (I already know how to program this; its a bit simpler than the Pi and there's only so many different languages I can be arsed to learn).  There will be a position detector on the hands so that the Arduino knows where they are and it will automatically compensate for time drift by adding or subtracting a few steps each hour.  The hardest part is going to be setting the time - 'real' clocks have a clutch on the spindle so that you can just whang the hands round but I would like the Arduino to do it automagically.  My plan is for the Arduino to go through a setup routine each time it is powered up, so it needs to turn the hands to a point where is knows where they both are; then calculate the number of motor steps required to get to the 'real' time, and then crank the motor as fast as it can (either forwards or backwards) to set the hands correctly.  If this works as planned it should look really cool, and  you should never need to touch it, although compensating for summer time/GMT is going to be a bit of a chore.

Anyway, the end result is that the mechanism looks pretty good and works a treat so far, I just need a cheap Arduino and a few days spent in the programming room before fitting it into a case.  I was originally planning to use it for the garden, but it seems a waste to hide those luverly gears away inside a housing so I'll get the programming working and then decide where to put it.  Non-rude suggestions are welcome.

Metal storage in the workshop has long been a problem.  The raw material comes in a variety of sizes, and once some of a length has been used, the remaining stumps end up swilling around the bench and getting in the way.  Time to resolve this, and it turned out to be much easier than I had thought.

The long pieces - up to around 1 metre long - are all now stacked neatly on a rack which is fixed to the wall.  The rack is simply two strips of slotted angle from the junk pile with steel rods welded on at around 45 degrees, and once the angles are screwed vertically to the wall the metal bars are just laid loose on the angled rods.  Works a treat, the pile of spider-infested metal that used to live in the corner is now a neat and easily accessible stack on the wall and the spiders need to find some place else to live.

The shorter bits provoked a bit more head scratching.  They come in all sizes, from a couple of centimetres up to 40-odd cm.  The solution was a couple of lengths of plastic waste pipe, sawn into various lengths and gooed to a piece of MDF with that excellent 'No More Nails' stickum.  I also gooed each piece of pipe to its neighbours and the end result is a pretty solid cluster of tubes.  The shortest pieces of metal are too small to fit into a tube - they all jumble around in the bottom and you can't get 'em out - so they ended up in an old plastic storage box.

All in all a neat and easy solution, and the workshop looks heaps better for it. Oh, and I can now find stuff as well :-)

A couple of months ago I mentioned the cows painted on the wall of the house in the village.  I recently bumped into the artist and he told me that a couple of other people had asked him about painting cows on their walls, and the first of these was finished a couple of weeks ago.  I can't explain why, but I really like this idea, if we had a painted wall I might ask him to do it here.

We took the kart out for its second outing this year last weekend with disappointing results.  It was one of the hottest days of the year, certainly the hottest we've seen at the track - announcements over the tannoy all day reporting on the ever-rising temperatures and pleading with everyone to drink more.  There was racing the day before, so the track was full of grip, but man, was it hot in the full race overalls, hard hat, boots, gloves, rib protector, phew! My driving performance was rubbish, though - braking too early and too much; too slow into the corners; leaving too much space in front at the start (just asking for someone to drop in there), the list of errors goes on.  I was better at this last year - not good, but better - and it seems that not racing for around 9 months means that I have completely lost any track skill I once had. As the day went on, all the drinking started to take its toll with water sloshing around in my bilges, and the old neck started to give out in the same way as the month before and the last few laps of the final had me flopping about like a rag doll.

I do have a bit of an action plan for next month.  A new set of tyres to replace the old five race set, and a bit of effort to move the seat forwards slightly to increase the grip at the front to make the beast turn in a bit better.  I also plan to follow Jon's advice and exercise the old neck by working it against a weight as well, and then its just a matter of not being such a wuss when out on the track.  Get a grip, man.

I've also been doing some deck repairs, a bit warm for clambering about under there but I need to make the most of the fine weather.  A couple of the deck boards have rotted and needed to be replaced, and over the ten years that the deck has been there some of the foundation posts have subsided and pulled it out of shape.  Replacing the rotten planks was easy enough, and I re-levelled the rest of it by pulling out three boards in the middle, unscrewing the joists from the supporting posts and jacking the whole thing up with as selection of car jacks until it was level, then replacing the screws.  A lot of huffing and puffing, but its done and already looks better.  The last remaining job is to pressure wash the whole thing and then paint it with some non-slip deck paint - unfortunately the rain water tank has gone dry with the lack of rain, so this will have to wait until its filled up a bit, the old pressure washer consumes water at an astounding rate.

The fine weather also means that I have been flying the tricopter quite a bit, and I am very slowly getting better at it.  Not had a crash for some time now, but panic still very quickly sets in when the thing suddenly sets off at speed towards the village hall or a passing pedestrian.  I can now do the banked turn thing, but the flight controller obviously thinks that more power is needed for this and it comes out of the turn at supersonic speeds.  I'm still having trouble working out which way its pointing when it is a distance away, and when its a long way off I'm still having trouble deciding if its high, or distant, or both, making it hard to judge where its going to come down if an emergency landing is required. Still, onwards and upwards.

And finally, the latest medical news.  I'm still in good shape, in spite of the hormone injections adding around 5 kilos to my weight and giving me a dull headache most of the time.  The good news is that the PSA reading is now down to 0.3 (the closer it is to zero the better).  We saw the oncologist  a week ago, and he agreed without a fight to refer me to the Royal Marsden in London, we should hopefully get an initial consultation with them by around the middle of August, then see where that takes us.  More forwards, please.

Next month:-  Charlotte and OB came to stay with us a few days ago, and we were going to play chess only to discover that we had the pieces but no board to play on, so I've started making a rough board, progress report next month.  I've also agreed to build some picture frames for them both, and hopefully I'll have some better results to report from the next kart race meeting. I was going to attack the Arduino temperature sensor that is misbehaving, but the fine weather has meant that I have spent most of my time outside so this will have to wait for some cooler weather.