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.....

Monday, 30 December 2013

Xmas and new year update

Well, here we are at the end of one of those 'good in parts' years.  This is the usual round up of recent activities and a peep at what is coming next in 2014.

Let's start with OB's chess set.  He has shown an interest in playing chess recently, and you can't play unless you have a board and pieces to play with, so between us we knocked up a set for his birthday.  (We have a weekend in December every year when the grandkids come to stay and while Charlotte goes off shopping with the Boss, OB and I make stuff in the garage.)

I couldn't face the thought of trying to turn up 32 assorted chess men - I don't have a wood lathe, and although I can turn small stuff in the metal lathe its not something i would describe as a 'core skill'.  So instead we made a more contemporary set with all of the pieces made from square timber with various shapes hacked into the top ends - so a rook has grooves reminiscent of battlements; the bishop has a pyramid-shaped point, and the knights look like..errrr.... horses.  Pawns are plain blocks, and the kings and queens have machined alloy 'crowns' and a bit of groovage on the flanks.  Once set up it didn't take long to finish them, and although they could probably have done with another coat of danish oil, they look fine.
I made a board for myself a while back, and realised that with a bit of care I could cut precise squares on the radial arm saw (the Saw of Oblivion) by setting up an end stop and trimming the squares across both length and width.  The fine saw blade gives a clean cut, and the bits don't need any further work before sticking them to the baseboard.

The base is made from two sheets of 6mm plywood, glued back to back and at 90 degrees to each other to try to stop them from warping. A bit of careful marking out and I glued the squares on to the first quarter of the board, making sure that each piece was snug against the ones around it.  Once this part was dry, repeat for the other three quarters, then trim the edges of the whole board very carefully on the saw so that the plywood and the squares were flush.  A quick edging of beech, a bit of heavy sanding with the sanding machines and all done.

So that the pieces and the board stay together, we made a box to fit under the board.  I had some nice pieces of oak that we cut to form the sides, with the corners cut with finger joints made with a straight cutter on the dovetail jig.  Some 3mm ply for the base, a set of rubber feet, a pair of brass hinges and a ball catch to hold the lid on and we're done. Last job was final sanding and a hefty slap of danish oil applied with considerable style by OB to bring up the colour of the walnut and maple squares on the top.

Looks really good, OB is pleased with it, and it saw a very close run draw between OB and Jon on Chrismas day.  Mission accomplished.

Next up, we've been looking for a long time for a replacement for the table lamp in the hall - it has been around for ages and  doesn't really go in this house.  After exploring other options I decided to have a go at making a shoji-style wall lamp.


I've left off some of the obviously Japanese-looking details, and focussed instead on a simple structure with very slim frames - although the wooden parts are very slim, the cross-halving joints give the whole thing a surprising amount of strength and it works pretty well.
 The framework is made from cherry, and the bulb is hidden behind a sheet of hand-made paper with a very coarse texture which softens the light quite nicely.  Unfortunately it uses one of they new-fangled low energy light bulbs which give a light that is a bit too white for my liking, but it does the job OK.  I'm not too happy about the cable dangling underneath it, so I think I'll get me little hammer out and hide the wire inside the wall.

Last month I mentioned the music player I had built using a Raspberry Pi and a some software called 'music player demon' or MPD.  The Pi reads my music library off the server and pours it out of its audio port into an external amplifier, with the control of what it plays being driven by an app on any android or tablet, or iPhone. If you've ever looked at Sonos kit, that's pretty much what it does.

MPD Pi in its case
Its been running for the past couple of months, and I've tried a number of different apps to control it, and having run it for a while upstairs in the study it recently was moved to the kitchen.  Its a good measure of how easy it is to use, and how well it works, in that the Boss is happily playing some bangin' choons on it right now downstairs in the kitchen.  

The MPD software runs on the linux Pi, and can be downloaded from here.  There are several apps available, I've only tried the free ones and in my opinion the best for the iPhone is called MPoD.  For android there is a much bigger choice, my personal favourites are MPRemote and MPDroid. It works so well that I will probably cough up the cash for a couple more Pis (Pies?) and put one in the lounge and one in the study.

Last in the list of things for this month is the model engine.  Well, not built yet, but I've been doing loads of research and designing and we're about ready to start ordering materials.

I'm expecting it to take a few months to build, with a fair bit of trial and error along the way.  I've wanted to build an engine for years, and having done my share of rebuilding 'real' engines I know that there's nothing like that moment when an inanimate and slightly sulky pile of oily metal parts splutters into life for the first time and becomes a living breathing thing.

Prototype carburettor
The design will be a bit different.  Its a 2 stroke for a start, with two horizontally opposed cylinders, and because 2 strokes usually use the crankcase pressure to 'pump' the fuel/air mixture into the cylinder, this arrangement will not work as the opposed pistons cancel out the pressure.  Instead it will have a secondary pair of cylinders that will suck in the charge, compress it and then deliver it into the 'firing' cylinders for the 'bang, whoosh!' part.  I came up with this idea by accident, and only later discovered that the bloke who originally invented 2 strokes used this on his first engines.  If I think about it a bit, there's no reason why I can't use the pre-charge cylinders to act as a supercharger.

... and seen from the other end
It will also be quite big, because making something as complex at really small scale is very difficult with my chubby fingers, so the capacity will be about 12cc, and the overall dimensions around 140 x 80 x 60mm.  I could machine all the parts from solid chunks of metal, but that is an expensive way to produce a floor full of swarf so I plan to try my hand at casting some aluminium.  I reckon I can build a simple furnace with a couple of clay flower pots, a hair drier and some charcoal bricks, and I can make the patterns for the castings from sand-packed styrofoam which vanishes in a puff of smoke and flame when confronted with boiling aluminium.  

So how far have I got?  Designs are finished enough to make a start on hacking up some metal, and I have made a simple carburettor (probably the most complex part of the lot) out of alloy bar and brass just to prove that the design works - tested it by putting the fuel feed pipe in a jar of water and blasting compressed air through it, producing a very satisfying mist spray out of the other end when at full throttle, though it took a while to mop up the puddles afterwards.  I've made some patterns for the 'real' carburettor and am about to start on the ones for the crankcase and the various manifolds before getting to grips with building the furnace.  Woohoo, can't wait.

I also am pleased to report that the tradition of making things from bits of junk appears to be hereditary with Sean's recent completion of a gyro-controlled camera mount.  Works a treat, as seen here in use on a bike, and an earlier version with a few glitches here on the back of the motor bike - we should call this one 'buttock-cam'.  Great job, and all based on a couple of bits of scrap aluminium hammered into shape in my workshop a few weeks ago.

A quick medical update as well.  I finished the radiotherapy mid-November, and as expected the major lethargy from that has taken a while to wear off.  I'm feeling almost back to full working order now and planning a new fitness regime starting this week with a view to getting back into shape and removing the flab round my middle (caused mostly by the hormone treatment, but not helped by my not training since April)  and getting back into TKD training by the end of January all being well.  Next steps are a follow up with the prostate team next week, and another with the haematologist at the end of January, fingers crossed but I'm not expecting any significant things from either of those two events.

An what of 2014, I hear you cry?  Well, the main tasks are going to be building the engine, and getting the kart ready for a full season's racing with a determination to come somewhere other than last.  I also have a coffee table to make for Sean and Mad, and OB has an arduino now, so probably a good deal of telephone and on-site support will be needed for that.  Having started the model engine work, I've also been looking at the design of the very old Commer TS3 engine, made by Commer trucks in the UK in the 60's and discontinued by them when Chrysler bought the company.  This engine was a supercharged three cylinder, opposed piston two stroke diesel with a distinctive exhaust sound, and I rather fancy making a working model version of one after the first engine is up and running.  The old timers among you may remember these engines, they had a nasty habit of kicking back and running in reverse with rapidly increasing revs and an inevitable very messy and noisy end - I once saw a driver  leap from the cab of his truck and leg it away from the vehicle at amazing speed just before the engine burst, filling both the cab and the roadway with oil, smoke, and bits of very hot metal.  I'll try to avoid that fate if I build one :-)

Onward and upward.  Time to order some metal and locate a couple of flower pots for the furnace, I promise lots of pictures for next month.

Friday, 8 November 2013

Airbrushing and some other stuff

Its been a bit of a slow month with construction projects.  I started radiotherapy on the 30th September, and the daily visits to the hospital kinda take up a few hours of every day, and not leaving much time to do stuff.  The radio is going well, the only side effects so far are a bit of tiredness (probably due to getting up early every morning, something I've got out of the habit of since retiring) and the need to pee a bit more frequently than usual. The staff at the cancer unit are fantastic, and us patients have a good old laugh while waiting our turn on the machine, so I will almost be sorry when the fun comes to an end on the 19th.

In spite of this malarkey I've still managed to get some stuff done this month, so here goes:

Cherry blossom airbrushed on wall
First up, the airbrush.  I've been prowling around looking for things to paint ever since I got this magic gadget, and have finally found a couple of targets.  The first is a bit of cherry blossom on the wall of our bedroom - much agonising before starting spraying, and its turned out a bit darker than I wanted, but for a first attempt its not ended up too bad.  The worst part was lugging the compressor up and down the stairs, it must weigh around 50 kilos so its not exactly portable and the corners start to dig into your hands after 10 seconds or so.

Cherry blossom detail
Making the masks from adhesive masking film is easy enough, but this stuff is a bugger to stick to the surface - the static in the film makes it jump out and stick to everything it sees, and getting the stuff to lay flat on the surface is a nightmare.  I decided after this little episode to try sticking on the plain sheet first and then cutting the masks in situ.

Top frame of bed with leaves
Having done the wall, it seemed a good idea to add a few leaves to the top bed rail as well.  It needed a new coat of white paint anyway, so I gave it the airbrush treatment while it was in the workshop.  It came out pretty well, although the same problems with positioning a pre-cut stencil meant that a couple of bits got missed.

Racing tortoise on spare side pod
Pumped up with these successes I decided to have a go at the kart side pods.  These are black and boring, so I have been looking for ways to brighten them up for a long time.  Of  course, they take a bit of a bashing on the track, so I'm not expecting the paint to stay on for long, but I thought I would try the process on the spare pod that we have and see how it turns out.  This time, I stuck the mask on in a single sheet, and then cut it in position - its certainly easier doing it this way and if I don't lean too hard on the scalpel there's no visible cut marks on the plastic pod.

I've learned a few things from this last item.  First, the background really needs to be a good solid white to give the colours some brightness, but the acrylic white that I have is just not man enough for the job so I will try some white car primer next time, it should key well to the plastic and will give a good matt surface for the acrylic.  Second, the paint is all water based, which makes cleaning up easy but it takes a long time to dry in between colours, so I found that a quick blast with the hair drier dries each coat nicely. Third, spraying through a bit of old mesh material gives a neat spotted effect which suggests reptile scales.  And last, don't shake the airbrush when its full of paint and the cap isn't on the paint cup  :-)

I'm encouraged enough by this test pod that am planning to do the real ones as soon as I can  pluck up the courage, though I'm not sure whether to go with the tortoise or something else.  Are we going to look good next season, or what?

The other major project this month has been to turn my Raspberry Pi into a dedicated music player which can be controlled by a phone or tablet. 

I've had this little widget for some time, and had always intended that it would eventually end up being built in to a spare monitor to run a home information screen, showing things like the state of all the door locks; temperature; calendar events coming up; to-do lists; weather, and so on. It runs a slow but adequate version of linux and all I would need to do would be to build a 'home control' web site:  however, this proved to be a bit of a problem because all of the web browsers are either a) slow; b) won't display all of the content, or c) both of the above. This has put a bit of a stopper on the project and while I puzzle out a solution the Pi has been relegated to a test bed for the stepper motor in the Magic Clock.

I have decided to buy an Android tablet, and this prompted me to think that the home control information would be easy to display on this kind of device.  While thinking this through I wondered how to play music through a tablet without downloading 5000 tracks to the device, and this led me to start looking at ways to do this in various places in the house without having to turn a PC on.

It turned out to be much easier than I thought it would be.  Basically the Pi needs to download a free app called MPD, then another free app called MPDroid on the tablet/phone, a bit of configuration and we're off!  I also bought a neat little case for the Pi for a fiver from a nice man on ebay to give the whole thing a professional appearance.

The Pi runs on the house network (this one is wired at the moment, but will use wireless in the kitchen where there is no handy network point) and is mapped to the server where all the music files live.  The tablet/phone shows a list of all the files and allows you to select the music you want to play and change the volume - I'm still playing with it, but I think you can also set up playlists.  It works a treat - surprisingly, its quite quick, and its pretty neat to have music playing in one room and be able to turn it up or change the track from another room. The plan is probably to buy a couple more Pis? Pies? Pees? to run in the kitchen, lounge and in the landing/study area.

And last this month is a picture of me and OB being pirates.  Shortly after the picture was taken he said something so funny that I was absolutely helpless with laughter for about five minutes, and sitting in the hospital waiting room the next day I remembered what he had said and started giggling again.  Yo ho ho and a bottle of rum

Next month:  radiotherapy finishes on the 19th, so more time to start butchering wood and such, and a new car on its way for The Boss, plus the build up to Xmas and we may have the new tablet by then. I'm also looking a designs for a 3D printer and/or a 3D milling machine (same guts, different foo-foo on the top), thinking of building one of they sometime soon.

Tuesday, 1 October 2013

October update

Doing stuff is still getting in the way of writing bloggery, and this is how it should be, so this is the current state of the game at the end of September.  The main events this past month have been the Magic Clock and the airbrush, and in response to a couple of constructive comments I am trying to include more pictures and a bit less wordage - however, I've never been a man to use ten words when a hundred will do, so its unlikely I'm going to change now :-)

First the Magic Clock.  I've been banging on about this for a couple of months now, ever since I discovered that I could make gears on my little milling machine. Well, here it is, pretty much finished.
Magic clock - finished
"What makes it magic?" I hear you cry, so this is why. Although the clock is powered by electricity, it continuously stores a record of how many steps the motor has done since midnight on a small SD memory card and uses this to remember the time when the power is removed and when the juice comes back on it 'fast winds' to the correct time and then resumes normal timekeeping.  As it runs normally, it constantly checks that its not running too fast or too slow, and if it is it automatically adjusts itself.  Its seems silly, but unplugging it for half an hour so that you can watch it catch up is one of those things that you never tire of. Here is a short video of it just finishing its starting up routine:-


Goncalo alvez block with black streaks
The observant ones will notice that it fast winds, then hesitates before doing another quick squirt:  it does this because the startup winding can take a couple of minutes and it makes a secondary adjustment to compensate for this.   There are two LEDs on the front, one to show that its powered up and the other flashes when its making an internal adjustment.

This month I've made a big push to finish it off, starting with the purchase of a couple of hefty slabs of goncalo alvez timber and a less hefty chunk of black walnut, both from my local woodyard.  The goncalo alvez is a reddish timber with random dramatic black streaks, so I cut the chunk to make the most of these. Finished with danish oil and beeswax, all of the wood will gradually darken to a richer colour over time.

Fixings and cable grommet
The visible part is the brass mechanism - basically a pair of drilled plates with brass gears which make up the correct ratio between the minute and hour hands, and with a secondary gear train to the stepper motor which drives the whole thing.  No big deal in this part, other than the need to cut the gears and drill the plates with a fair degree of accuracy to ensure the train runs smoothly and without too much backlash.  It even has its own hand made miniature custom spanners to lock the hands on to the spindles

The mechanism is intended to appear to be hanging in mid-air and is contained in a glass fronted space to keep the dust and inquisitive fingers out. 
Stepper motor and drive module

The stepper motor and controller module came from China at a ludicrous price of around three quid including postage.

The part that drives the stepper motor is an Arduino microcontroller with a few add ons - a module to hold a SD memory card; a real time clock module, and the controller module for the stepper motor. All of the modules and the Arduino came from my friends in China with a total cost of around fifteen quid.

The software is in two parts - one to set the whole thing up, and the other to run the clock.The setup routines set the real time clock module to the current time, and creates the SD card file with a zero entry.  Once the setup routine has been run, the mechanism has to be physically set up with the hands pointing directly at 12:00 before loading the 'run' software.  The clock reads the data from the card (zero the first time out), compares it to the 'real' time and calculates the number of steps that the motor needs to run in order to catch up.  Once the fast wind is completed, the clock also calculates how long this process took and kicks the motor the right number of steps to compensate, then settles into a routine where it pumps the motor by n steps, compares the result with the 'real' time and makes any required adjustments by either pumping in a few more steps or stopping the clock for a few steps-worth.  In practice these adjustments are only around 10  - 15 steps worth (there are 36864 steps in an hour) and occur every couple of minutes - at the moment the software is full of information messages which affect the running speed of the software and I expect to be able to fine tune it better once the software is cleaned up a bit more. All along the way the number of steps completed by the motor is saved to the SD card, and the next time the clock is powered up after a power failure it reads this number and resets the clock.  Simples.

The software has taken me a fair time to write, C++ not being my first language, but with a lot of trial and error and help from Jon with the SD card it now works. There is loads of online help for these little computers, but although there are countless examples to play with, none of them ever seem do what I want to do.  Unfortunately - like there is in the linux community - there is also a fair number of self-styled 'experts' out there who when you ask a simple question make it their mission to make you look as stupid as possible instead of giving a plain answer, or giving a solution that is so complex that its impossible to understand. I have to assume that these people a) are twelve years old, and/or b) have a very small willy. If anyone wants to have a laugh at my code, or even have a go at building their own version of the Magic Clock, let me know

Rear access plate
The electronics are crammed inside the wooden slab, mounted on a metal plate to allow them to be slid out in case of internal derangement.  I'm expecting that the SD card will probably be the part that is most likely to fail, so I've made it accessible from outside with a retainer to prevent it being popped out of its slot by accident.

It was a real pig to hack away the wood to make the space for this, and in retrospect I realise that I could have split the slab in half and routed out the hole in both halves then glued it back together again.  Didn't think of that at the time, so it was out with my Japanese chisels and my little hammer.

Japanese oire nomi chisels

Not clock related, but every time I use them I realise again how spectacularly good these chisels are.  They are made from the same type of laminated steel that made the Japanese swords so good at taking and holding a keen edge even after hacking up a few assorted bad guys.  The steel is  heated up and hammered flat, then reheated and folded over on itself before hammering flat again:  repeat a few hundred times or more and the steel develops the ability to be hardened to a higher level than most other steels while retaining its strength and chip resistance.  The chisels don't do much in the way of bad guy hacking, but they take a fantastic edge and hold it through a lot of hard timber.  By contrast, the english plane blade that I have had for many years takes a fairly decent edge but loses it very quickly, requiring frequent re-sharpening throughout even fairly light wood butchery, and this is the case with pretty much all of the newer tools that I have - the steel is mostly selected for its cheapness and not its quality and it is increasingly difficult to get any kind of a tool that works properly. I especially hate the tools which claim to be 'titanium coated' but which actually seem to be  made entirely of cheese with a lick of brown paint.  Having recently seen a bloke making axe heads with a tray of hot coal, a big 'ammer and an anvil I'm tempted to have a go at making my own Japanese steel edge tools.  Watch this space.

All of this has taken up most of September, and because I wanted to get the clock finished before starting anything else, it has diverted me away from my other exciting new foo-foo which is my new Chinese Airbrush.  

If you search the 'web, the general view seems to be that some of the best airbrushes around are made by a company called Iwata.  They may be good kit, but with prices starting around £100 they are outside my budget, so I'm off to China via Ebay.  Well, blow me down, here's a Veda WD180 airbrush which is pretty much the identical jobbie to the Iwata HP-SB (priced at around £180) at a bargain price of twenty-five quid including postage.  Found some online reviews which rated it pretty highly, so worth a punt.

Veda WD180 airbrush
Well the little beastie arrived a couple of weeks ago after the usual 3 -4 weeks shipping, and its an absolute ripper.  Beautifully made and finished, and comes in a padded box just like the real thing.  In fact, its so much like the real thing that I suspect that it is made in the same factory as the Iwata.

I have a limited number of paints that I can use with it, and have only played with it a bit so far, but the first impressions are a) its a great bit of kit, works a treat, and b) its fiendishly hard to use.  The trigger presses down to release air, and pulls back to open the needle to let the paint into the airstream, but getting the co-ordination right is a bit of a challenge.  Like all these things, practice makes it better, but I need a fair bit of time before I am going to be able to do a Banksy on the side of the village hall.  So far, this Iron Man  is the best I can come up with - 

I have already found out that the water based paints which I have are really easy to use and clean up, but they only work on fairly absorbent surfaces like paper - on a hard surface you need to spray a bit, wait for it to dry off, then spray some more, and while waiting for it to dry you need to clean the airbrush to stop the paint drying inside (which is easy to do but tedious and wastes the paint).  I'm going to experiment with thinner-based paint and see how easy that is before re-painting my computer case with the Donald Duck picture. 

I've also discovered that the freehand work that you see people doing on Youtube is about as easy as knitting with fog underwater, and my best option is to use multiple sticky stencils - another new skill I have to learn.  I'm planning some flames on the kart side pods for next season, so now that the clock is done that will be my next focus.

And last, a quick medical update.  At long last I started the radio therapy yesterday, seven and a half weeks of going to the hospital every day, spending an hour drinking a gallon of water and three minutes in/on the radio machine.  First observations:  plain water is only interesting to fish, dogs and horses; the staff at the centre are really great, couldn't wish for any better; and while in the machine, they play music from the 1960s.  I thought this was a carefully thought out caring idea because most of their patients are aged 60 plus, but apparently they only have three CDs and this is the best of them.  Although the treatment itself only takes a few minutes, by the time I've hiked there and back its about a two and a half hour for the round trip.

I also had the last of the hormone injections today, can't say I'm sorry to see the back of them as they give me a constant dull headache, stop me sleeping properly, have added a couple of kilos to my waistline and generally make me less enthusiastic than usual. This last one should have mostly worn off by the end of October and I should gradually get back to normal after that.  With the radio therapy finishing mid-November I aim to get stuck into some fitness work after that and return to some form of martial arts training after Xmas.  Can't wait.

Next month?  Well, the airbrush will get a bit of a pasting as soon as I can get the paints organised, and I need to rebuild my desktop PC with some new go-faster guts provided by Jon - just received the memory today, but this will entail re-loading all the software so it will be probably the best part of a week loading discs and staring at the screen.  There's also the design work for the new 'Star Chess' game that OB and I have been talking about, some outside work to do in the garden before the weather closes in, and of course trekking back and forth to the hospital every day is going to limit my time a bit.

As the Honda advertisment used to say: "more forwards, please"

Wednesday, 4 September 2013

Late August update

As usual, the work of the retired person is never done, and there's been lots occurring this month.  Lets look at some of it:-

First, a bit of a rebuild of my ancient air compressor.  I originally built this the best part of 30 years ago from an old compressor unit from a scrap fridge and an air tank off a lorry, and even had the build featured in one of the Model Engineer type magazines.  Given that the compressor unit is probably around 40 - 50 years old, its done sterling service - it blows up the tyres; blows dust and gunk off; and has done a huge number of spray painting jobs (including a set of kitchen cupboard doors; large parts of the old Morris van, and a complete Vauxhall Astra).  After all these years, its leaking a bit and the pressure switch - made from various junk including a piece of an old truck inner tube - was looking a bit sad. Time for a freshen up.

The main reason for looking at the compressor was because I have also ordered myself a new airbrush (yes, from China) and I will need a decent adjustable air supply for that.

It quickly became apparent that a new pressure switch sourced from the UK was going to cost £30 plus, so off to China to buy the same item for around £6 including postage.  Inspired by this find, I also ordered a new moisture trap for the princely sum of around four quid.

New moisture trap
Delivery was around 3 weeks, so in the meantime I set to work dismantling the old girl. For those that don't know, the back heavy lump in the bottom of a fridge is a steel bottle containing a motor driving one or two pistons.  Air is drawn into the space inside the bottle through a pipe, and is then sucked into the cylinders, compressed, and forced out through a narrow pipe. The bottle also contains a small amount of oil which lubricates the pistons via a crude pump arrangement, but unfortunately this also produces a fine mist of oil which gets sucked in with the air and which is guaranteed to ruin any freshly applied paintwork unless its removed first.

The rebuilt compressor
I took the top off the bottle by sawing through the weld seam with a hacksaw - if you choose the right spot, no metal filings will find their way into the innards.  My plan was to run the intake of the compressor directly to the outside of the bottle, thus stopping the oil from being sucked in with the air, but the contraption of pipes that I had to create to do this made the air intake much smaller than before and the compressor ran massively hot after only a few minutes, and it was clearly struggling to suck the air in fast enough.  So I reverted to the original design and will deal with the oil mist by means of the new moisture trap.  Topped up the oil a bit and tack welded the lid back on the bottle.  A bit of a tip here if you do this - after tack welding, make sure that you cover the joint around the bottle with tape or silicone sealer, if you don't the air gets drawn in through the joint instead of through the filter, and the noise it makes resembles the sound of a thousand centipedes farting.
.. and from the front, the string operates the drain valve on the tank

Earlier than expected, the new pressure switch arrived, a bit of hacking about of the pipework and its up and running.  Unlike the old home made switch, the new one is adjustable and also has an unloader valve which releases the pressure in the compressor itself when it switches off so that when it turns back on there is no pressure in the cylinders - a good idea to save wear on the compressor, and a very satisfying blast of air every time it switches off.

I plan to use the new airbrush on the bench, so I will need to run a long hose from the compressor and mount the moisture trap on the wall above the bench.  The moisture trap also has a pressure regulator, so it needs to be close to where I'm working.  Pacing up and down now waiting for  the postie to deliver the airbrush, and from then on anything remotely flat that stands still long enough will end up with an assortment of flames, skulls, dragons and flags.  Can't wait to get stuck in, though there is a lot of dark muttering from the kitchen every time I mention it.

Next, I've finally finished the water alarms.  When we built the house, I planned for these to be installed in both the utility room and the kitchen, as a water leak in a timber frame house with solid wood flooring would be a complete disaster. Over the years we've had occasional explosions in washing machines and I've become a bit paranoid about them, so a couple of weeks ago when the washing machine stared leaking and it turned out that the rubber seal on the door had a tear it prompted me to finish off the alarms.

The rubber seal was fairly easy to replace - you need to remove the top and the front of the machine and its pretty easy after that - although the genuine Miele spare cost the thick end of £90 plus postage.  Gulp.

Indicator panel in utility room
as well as the blow-your-head-off siren
The alarm is a simple Velleman kit which I installed inside a standard double wall box, with a trailing wire to connect the sensor - two stainless steel plates held around 3mm apart with a block of plastic and laid on the floor under the machine.  In the utility room, the box is in the wall behind the washing machine and connects to an adjacent CAT5 wiring point with a short patch lead, as well as a second lead that goes up inside the wall to emerge in a single wall box above the worktop.  This box contains a set of indicator LEDs and a fly cable to a siren mounted underneath the high level cupboards, as well as a kill switch for the siren and a test button. The test button has already given me endless entertainment at the expense of unwary visitors :-)
The unit in the kitchen

The CAT5 connection provides 12 volt power for the sensor, LEDs and siren, and also has a feed back to the Arduino to tell it when an alarm is triggered. I plan to rig up another central siren fed from the Arduino to kick off not only when the water alarms go off but also when any other alarming event occurs - for example, if the back door should open after 1 am.
The alarm unit in the kitchen is set up in much the same way, although its mounted in a cupboard which unfortunately muffles the siren a bit, but its still loud enough to trigger a change of underwear when it goes off unexpectedly.

Then there's the brass clock. Since last month, I've stopped drooling over it and made a ring face from 3mm thick aluminium sheet, mounted on to a satin black steel carrier plate and a small bracket for mounting.  I plan to mount it to a seriously chunky block of timber, then encase the clock proper in a glass-panelled shallow box - hard to explain, but you'll understand when I post some pictures hopefully next month. In the meantime, its been running more or less continuously, driven by the Raspberry Pi for now, although it will be eventually driven from another Arduino hidden inside the timber chunk. 

I've started writing the software, a bit tricky as the clock will need to know what the real time is without any feedback from the mechanism, and if there's a power failure it will need to automatically adjust its own hands to bring it back to the correct time. The plan is for it to continuously count the number of pulses it has delivered since 00:00 and convert that into time which it will compare with its own internal real-time clock. 

The glass panels will all be engraved with some suitable text, and I'm going to try edge-lighting the glass with high brightness LEDs in the hopes that it makes it look as if the lettering is hanging in mid air. Its gonna be a pointless beast, but a beautiful one

Last month I attempted to play chess with my grandson, OB, but failed as I had a set of pieces but realised we didn't have a chessboard. So this month I made one, and when OB and Charlotte came to stay last weekend we tried it out a few times.
As usual, its made from scraps, starting with a square of 18mm MDF.  I already had some offcuts of yew and some left over maple from the flooring, so I cut these into strips and planed them down to around 3mm thick.  Trimmed the strips to the correct width on the radial arm saw, and then set up a stop on the same saw to cut 32 squares of each colour.  I also had some left over strips of dark imbuia which I planed to around 3mm thick. 

Starting from the centre, I glued the first square and let the glue dry, then added a strip of imbuia and the next square pressed against the first.  Long strips of imbuia in one direction, and short bits the other and fairly quickly I had a board.  A final strip of imbuia all around the four edges, a strip of light wood salvaged from some venetian blind slats glued on all four sides, and we're done.  It took some fairly brutal work to sand the top flat - first took off the big sticky-up bits with the angle grinder, then the big plate sander with 80 grit paper, and finally the small plate sander with 240 grit wet and dry (much better than sandpaper, o yes). Three coats of danish oil, final rub down with a fine scotch pad, a good whack of beeswax and some serious elbow grease polishing with one of those micro-fibre dusters, a set of stick-on felt feet and it looks pretty good.

I'm pleased to report as well that the kart race in August went a lot better than the previous month.  The weather was perfect, warm but not too hot, and spending the money on a new set of tyres made a massive difference.  (Note to self: replace tyres every two or three races in future, instead of trying to make a set last all year.) I ended up having a couple of close runs with one of the many guys who are always faster than me, went quicker than him on two of the four races but never managed to pass him.The new tyres helped, of course, but I was a lot better at braking a bit later and not as much, as well as trying to resist the inevitable elbowing in the first few corners.  All in all, a good days racing.

Some movement on the medical front this month at last as well.  Rather than just opt for the standard radio therapy treatment from the local hospital to fix my prostate, I wanted to explore whatever other treatments might be available as well, so I persuaded my GP into referring me to the Royal Marsden in London.  This is a world-renowned cancer centre and one of only five hospitals in the UK to have a Cyberknife machine.

Standard radio treatment bombards the tumour with low power beams over a period of around seven weeks - it takes this long because the beams can damage healthy tissue, so the dose has to be strictly limited.  The Cyberknife (great name, eh?) fires multiple beams at the target from all different angles, so the tumour gets the full dose, but the surrounding pipes don't get damaged.  It was originally developed for use on brain tumours where surgery was not possible and standard radio therapy would cause too much damage.  The machine is very accurate, and automatically adjusts for the body moving as you breathe.

Well, we saw the Marsden last week, with good and not so good news.  The less-good news is that the Cyberknife treatments are only being done as a series of strictly controlled clinical trials and I don't qualify because of my previous colon cancer and my ongoing lymphoma.  The good news is that although they have a variety of more conventional radio treatments available, the one they recommend happens to be exactly the same as the one that is provided at the local hospital.  No point in trekking to London for that, so I've started the wheels moving here with the expectation of radio treatment starting late September and finishing around 8 weeks later, some time in November.

And finally:  busy flying the whizzcopter the other day down on the playing field when I was approached by a lad of maybe 10.  "Cor" says he, " that's great, can I have a go?"  "No" says I, "its too dangerous".  Lad thinks for a moment, then says "did you make it?", and when I told him 'yes' he says "Are you a scientist?".  "No", I says, "I'm a genius".  "Oh, right" he says and tootled off home, presumably to tell his mum that he'd just met the village idiot.

And next month?  If the airbrush arrives there will be lots on that, plus I should be well under way with the clock.  Vroom, vroom

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.

Thursday, 13 June 2013

June update

Loads been going on this month, a quick summary as follows.

First, the Whizzcopter.  I'm pleased to say that updating the fimware on the flight control board has made a massive difference to the flyability of the tricopter.  During this fine weather, I'm flying every couple of days or so, and havn't had a serious crash yet, although I managed to fly it completely out of the village playing field and dropped it gently into the farm field beyond.  The field turned out to be waist-high with nettles and other savage plants, and it took a while to find the machine - perched vertically on the edge of a ditch with around two feet of water in it.  Lucky or what?

I still havn't mastered flying it towards me, nor the execution of banked-turns-with-simultaneous-altering-of-throttle, and the dropping into the field escapade highlights the fact that when the beast is high and far away its impossible to tell height from distance. Its also surprising how much even a light wind can blow the thing about - changing the propellers for a smaller size made it better, but its still a handful in anything but almost still air. If the fine weather continues, I'll keep flying.

Then there's Sergei.  After last month's exciting news item of him piloting the whizzcopter, I've had a message and picture from Alexander Orlov from Meerkovo with some sad news.  The message reads as follows:-
Sergei RIP
"Am having to tell bad news about Sergei.  I know him all my life, and until recent he was in charging of IT department, but wanting more adventuring.  After much training (almost ten minute) he is put in charge of Meerkovo Airways first airplane.  However, flying performance was not good, mainly because he spend much time in cabin playing 'hide the sausage' with funky new stewardess Tanya instead of pulling stick at front.  After too many crash landing, we have suspend his fuzzy ass, and he taking this rejection much badly. Picture show how we find him in workshop. Still, he never good at IT, and worse at piloting, so no great loss.  Am more concern that new airplane can not be found, and Tanya so upset about Sergei that she have disappear too."

Grandfather clock wood pen holder
A few small things built this month.  The first is a pen holder for my desk, made from the remaining fragments of the ancient grandfather clock carcase.  Once all the woodworm, dry rot, nail holes and bullet wounds were cut out, there wasn't much wood left that was usable and this little item finishes off all that remained, while all of the left over unusable stuff has been given a chance to serve again by providing light and warmth in the fire pit.
The fire pit in action

I'm still doing some low-level background work on the Arduino to make it deliver information to a 'status screen' to be driven by a Raspberry Pi.  The Arduino has been working fine for a long time now, turning things on and off and monitoring the status of door locks, lights, and other stuff, but the temperature sensors I used never worked properly.  These were LM34s, bought to match some sample code that I found on the web, but only later did I discover that they read temperature in Fahrenheit which required the software to then convert readings into Centigrade. A bit more research, ordered a couple of TMP36s which read directly in Centigrade, hack the software about and bingo! she works. Well, sort of.  The original sensors gave readings that floated all over the place, and one of the new ones does the same.  Playing around with things leads me to the conclusion that the sensor works fine and that the fault is in the wiring somewhere, so the Arduino box has to come out of the rack to trace the dry joint or bad crimp.  This is a bit of a trial because of all the wiring in the engine room, so I'll do this next month.

Power supply from PC PSU
I've also made a general purpose power supply for the workshop out of an old PC power supply that I've had kicking around for a few years that I am never going to use for a PC.  This conversion is pretty easy to do, loads of information on the web on how to wire it up, and the hardest thing was trying to connect and bundle all of the hundreds of wires that need to be tidily crammed into the enclosure.  I managed it without any blinding flashes or other incident and the picture shows the end result - the only problem is that the blue LED is so bright that it nearly sets your hair alight if you get too close:  "don't look at the light, Mary..."  The box dishes up pretty tightly regulated voltages of 3.3v, 5v and 12v, and I've already used it a few times to test various things to see if they work.  Useful things made from junk again :-)
Table with umbrella

Last month I built the garden table which has been a big success, especially now that the plants are getting a grip and flowering.  Its also just the right height to put your feet on while sunning, excellent.  With the recent fine weather it seemed a good idea to add a stand for the umbrella that has been home to several generations of mice and spiders in the shed for the past couple of years, so a bit of work with a boring bit, some scrap wood, a few screws and my little hammer produced this result.  Looks good, works well, another successful junk conversion.
Workshop floor paint job
I've also just finished painting the workshop floor an attractive battleship grey.  It nearly killed my back and knees, but its much easier to sweep up the wreckage and it brightens the place up a bit as well, and it should also stop the rain from soaking into the concrete and creeping under the door.  Since I've had the paint for the best part of five years I thought it was about time I used it - of course, it ran out after around three quarters of the floor was finished, so I had to buy more, and you can only buy it in 2.5 litre cans even though I needed less than a litre.  Ah well, I've got some spare in case I need to paint some other floor some other time.

Last Sunday was race day, the first time I've raced the kart since last October.  Near-perfect weather conditions, and a track with plenty of grip should have made for a great days racing.  However, my driving was pretty poor, with whatever skills I possessed last year completely forgotten, and by the last race my neck muscles were so knackered that I couldn't control the flopping of the old bonce against the g-forces.  Good fun for all that, but I need to build up the muscles a bit before next month's outing - Jon says I need to tie lead weights on my helmet, but I'm pretty sure the scrutineers will have something to say about that.

Last, a health update.  Just had the third of the hormone injections and done loads of research on the best place to get the radio therapy - probably in London, and I suspect I will need to get the local wallahs in a Kytherian death grip to persuade them to refer me.  I'm currently waiting for an appointment with the local oncologist to kick off that discussion:  'round one, seconds out!'...  

Next month: I will have the Arduino home control box to bits and sort out the temperature sensors properly, and I'm working on some storage solutions for the various piles of metal and other important stuff in the workshop, as well as planning a clock for the garden (probably driven by an Arduino and  stepper motors).  I have also been thinking for some time about building a 'thousand year clock', o yes: more on this later.