engineer

tim   .

                                                      


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.   hunkin

                                                         


cartoonist

 

LONDON ZOO TROPICAL AVIARY CLOCK
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DESIGN
INFLUENCES
AUTOMATA AND FILM
INDUSTRIAL AUTOMATION
TECHNICAL DETAILS
METALS AND PAINT
ZOOS
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DESIGN

 I don’t usually live a jet set life, but I first called in at the zoo to discuss the idea en route to the Makers Faire in San Fransisco. I’d sent in advance a contraption I’d made in 1981 called Air Raid. Two seagulls swirl around overhead and shit polo mints when you press the fire button. This obviously influenced the design for the zoo.

 The zoo’s offer had come from a wealthy sponsor who was already funding 50% of the tropical birdhouse renovation. He had recently expressed interest in adding a bit more to make it really special. Did I want to design something to tempt him? I knew immediately that I did – I liked both the location and the theme (the Victorians attitude to animals), but coming up with an idea was more tricky than I’d expected.

 
It didn’t have to be a clock, but I like clocks. People naturally gather to watch a performance on the hour. Clocks are also fortunately too ‘nerdy’ to count as fine art.  My first idea was to make a clock in a cage, but I was quickly told that this would not do – the zoo was busy removing cages and certainly didn’t want any new ones, even if it was only a clock inside. I then started exploring the rotating bird idea. I had a number ideas for mechanisms, scenes, ingredients, but they obstinately wouldn’t distil into anything simple. At the back of my mind was the Southwold pier clock – which often isn’t working perfectly, but as long as the boys trousers drop and they pee, the audience is perfectly happy. At some point I realised that a unifying strand was birds escaping, and this helped hone the design, but it still refused to reduce to anything simple.


Rejected caged clock idea


One of many early designs

Eventually, with the deadline looming, my enthusiasm to do the job got the better of my reluctance to submit a complicated design. I go through a cycle building something really elaborate, and then relaxing with more straightforward stuff for a while. The last project that had really stretched me had been my Mobility Masterclass arcade machine three years ago so perhaps by now I was ready for the next challenge. Anyway, the mysterious sponsor liked my crude animation of the clock, so suddenly the job became a reality. I always feel flattered and keen when a proposal is first accepted, and in this case my enthusiasm has continued, so I guess I wasn’t such a bad design – even though I remain nervous about its long term maintenance.

 

INFLUENCES

Saul Steinberg was an American cartoonist who most famously drew for the New Yorker in the 1950s and 60s. My dad was a fan and his enthusiasm infected me. Most of his work is now a bit dated but I’ve remained obsessed by one of his cartoons depicting the American way of life in a Victorian setting. It portrayed the state of the nation as an imposing pedimented statue, reminiscent of the Albert Memorial in London. The idea of capturing the spirit of the age in this manner really appeals to me.  I tried my own cartoon version a few years ago. Anyway, with Steinberg strongly in my mind, the concept of a statue celebrating the victorian’s confidence about their mastery over the animal kingdom seemed totally appropriate and appealing as a project. 

 


The 1951 Festival of Britain Guinness clock,
(note the toucans pecking the tree behind the doors) 

In the late 1940’s a cartoonist called Roland Emett was drawing ‘fantasy’ machines. He then started working with an engineering company to make his cartoon machines into physical contraptions. Guinness commissioned him to make a clock for the 1951 Great Exhibition, featuring the Toucan they used in their advertising. The clock was a hit and Emit made several more for English seaside resorts. The original London clock was moved to Battersea Park and I vaguely remember being taken to see it as a child and demanding to go back to see it again and again. I now can’t remember what it looked like, but the connection between toucans and clocks is obviously indelibly imprinted. 



The entrance to Hagenbeck's zoo in Hamburg, c1910. Hagenbeck was a flamboyant character who supplied zoos and circuses with wild animals and native people. His zoo was the first to remove cages and build fake scenery and mountains so the animals could be seen in their 'natural' habitat. The entrance expresses the victorian confidence in their command of the natural world perfectly.

 

 

AUTOMATA AND FILM

The process of making a clock like this is surprisingly similar to making a film. I’ve done both. Both tell stories. Both start with research, followed by a broad outline to sell the idea. Once the cash is agreed it’s a technical process of creating the material. Both are finished by a process of editing, which with this clock involved programming all the pneumatic rams and adding sound. The timing of each action is surprisingly critical, get it wrong and it jars in the same way as a clumsy film edit. Both film and clock involve disappointments and delightful unexpected surprises along the way. Both only come to life right at the end of a long and expensive process. The clock was certainly transformed by fine tuning the timings of the rams and adding the bird sound track. I’d never expected the finished result to feel emotional. 

Personally, I prefer making a clock to a film because the process of filming a scene is far more wearing and less satisfying than making a part for a machine. Filming is frustrating because it’s expensive and usually everything has to be done in a hurry. It usually involves lots of people and lots of energy motivating them all to get the result. I have done it and my films have been quite successful, but only on a few special occasions have I ended a day filming feeling content. 

In contrast, making parts in a shed is cheap, so it doesn’t have to be done to a tight schedule, and there’s a satisfying physical object to show for almost every day’s work. I know I’m a bit odd, but I feel alive with the smell of the oily machine tools, the sparks of the angle grinders and the white hot metal of the welding. To me it’s all much more sensual, battling against physics and the elements to get the result. It seems infinitely preferable to a hot film set, charming a group of people to get the result. If I worked as a complete loner, I would feel limited, but I have the luxury of working with a few other enthusiasts. And because there’s little or no status attached to this sort of work, they only do it because they enjoy it like I do.

 

INDUSTRIAL AUTOMATION 

Today, we are used to mass produced machines which have all have been through many prototype stages and modifications in production to make them reliable. It’s always really hard to make a one-off machine reliable. Trying to make a first prototype 100% reliable is virtually impossible. Sometimes my friend Will jokes that what we do for a living is to make unreliable machines. 

Fortunately we are not alone. A lot of machines are built as one-offs, particularly for industrial automation. If an industrial automation robot or conveyor system stops working a factory loses a lot of money. Nothing is being produced but the factory is still paying the staff and the overheads. In the UK, food factories spend in a particularly extravagant style to fix their production lines as quickly as possible.

 

Unlike consumer machines, the long term reliability of industrial machines is more important than initial price. Also, industrial automation companies have to try and make it possible for engineers to make reliable one-off machines using their stuff.

I like the industrial automation kit of parts, and use them for almost everything I make. My machines are still pretty unreliable to start with, but they usually settle down after a year or two and then become at least manageable if not respectably reliable.  My enthusiasm often gets the better of me so my machines are usually far too complicated and I sometimes have to go back to a machine twenty times to get it to this state. (My ‘Expressive Photobooth’ was the worst ever – I went back every week for two years, then rebuilt it and went every week for another year….but then it was built round a PC (consumer product), not a PLC(industrial automation product). 

 

For people used to programming microcontroller chips and making their own printed circuits the industrial automation kit must seem ridiculously expensive and curiously old fashioned, as there’s no soldering, the components all have screwed terminals and are connected to astonishingly large DIN rail terminals. My control boxes are usually at least 600mm square, the one for the clock is 800mm by 1,000mm. But to me it seems eminently sensible. Although I often solder my own printed circuit boards, when I’m trying to get a complete machine to work I have to swap seamlessly from software to hardware, a screwdriver is a more practical tool. If a control board is too crowded, I can only see it clearly when its on the bench, not when its installed in a machine in a typically awkward position. If I need to add an extra wire,  I simply pull the covers off the trunking and screw it in place.

TECHNICAL DETAILS

 

Pneumatics

I had the idea of using pneumatic rams to drive everything early on, but at first wasn’t even sure if they would work outdoors in all weathers. The rams are made of aluminium and stainless steel so they would be fine but I wasn’t sure about the plastic tubing and flow valves. My local pneumatics company assured me they had quite a few outdoor installations so I went ahead. Apart from plastic being affected by UV there is also the problem of condensation. The rapid changes of outdoor temperature means a lot more water then normal gets sucked in. The problem is that if any water reaches the control valves, it blocks up the tiny air passages and they stop working. It is possible to buy refrigeration devices to remove all the water, but these are expensive and bulky, so I was recommended a cheap alternative which spins the air in a vortex, throwing the water out.  

 

The pecking toucans

Having decided to use pneumatics, the two main technical challenges were getting the toucans to peck the pendulum reliably and getting the birds to fly and return to their cages without bumping into anything. Industrial automation parts don’t solve problems like these without some additional ingenious mechanical design. Both problems went though several prototypes before finding solutions. 

I first thought the toucans should each have a string connected to a small ram to pull them back.  The string could pull when the pendulum was on the far side of its swing and release when the pendulum touched the toucan’s beak. The result was that the weight of the toucans would give the pendulum a nudge every swing. This is the same principle as a gravity escapement (as used on Big Ben, and many other tower clocks) so it seemed a good idea at the time. Sadly it was a complete failure. It didn’t behave like a gravity escapement, more like pushing a child on a swing. Pushing with any significant force shortens the period of the pendulum’s swing. I eventually did get it to work by fixing the timing of the pulls on the toucans’ strings, but still did not feel entirely confident about it. As the timings were now coming from the logic controller, it was no longer acting as a true pendulum, and this gave me the idea of fitting a small ram near the top of the pendulum, giving it regular ‘pulses’ of air. This worked first time, had easily enough power to nudge the toucans and was self starting. So now it’s a complete fraud, the pendulum is a fake and its not even powered by the toucans. But its reliable, looks great and makes a nice tick-tock sound.

 

   

The Flying birds
There was no satisfying eureka moment in getting the birds to fly and return reliably. My initial problem was that the birds needed to be significantly bigger than my drawing to have any presence when flying. This meant the wings would have to unfold. I tried several unfolding and flapping mechanisms, but they all had problems. It was during one of these tests that I tried the curved supporting rods with the pivots on the rotating arm further out. This just looked great when the birds were flying so it remained. The eventual solution for the wings was to shape them so that they folded by themselves when they bumped into the cages. I could then use their air supply, intended to power the wings, for two cylinders on the ends of the arm. These pull the support rods inwards, pulling the birds into their cages, so their normal position is just far enough out to avoid all obstacles. I’m now amazed that they even seem to work in quite a high wind without crashing into things.

 

Unexpected disasters always happen. At one point we decided to cut down the plinth by 150mm. While lowering the frame with a turfer, a rope slipped, dropping the clock hard and bending the frame. We eventually straightened it by welding some short 100mm box section pieces together to make a 'beam' which we used with a car jack to apply an opposite force on the frame. How I would love to have a crane always ready in the yard.    

Near the end of the project I had a software problem getting the clock to start at the right time every day and keep good time – it just seemed very unpredictable. Logic controllers (like computers before they were connected to the internet) just don’t keep accurate time. The spec of my controller was an error of up to 45sec a month, about 10 minutes a year. It is bizarre that such sophisticated digital contraptions can’t keep time – I used to think quartz crystals were almost as good as atomic clocks but really they’re not much better than mechanical pendulums. I was aware of this , so I had incorporated a cheap radio wall clock to correct it, and it took a while to discover that this was the main source of the problem. It had been struggling to get a strong enough signal, surrounded by the metal clock frame and so was occasionally resetting itself, throwing everything into confusion. 

In the long term, I’m worried about the lifespan of the valves and cylinders powering the pendulum. They have to do 10 million strokes a year! I’m also worried about the lifespan of the compressor. Despite running everything at only 50psi, the clock uses a lot more air than I was expecting and the compressor runs for 8-10 minutes every hour. 

Postscript, five years later:

After the first few months I fitted a master valve which turns off the air supply to all performance rams, except when performing. This greatly reduced the time the compressor runs and its still going fine, currently 1500 hours since new. I finally had to change the cylinders that work the pendulum and escapement last year, they had done 50 million cycles. The valves were still working, but I swopped them with two of the performance valves which don't have such a hard life. 
The worst maintenance problem to date was the clock becoming unpredictable in chiming and sometimes not starting up in the morning. It took months and many visits to find the problem was just a loose collar on the hour hand which caused the hour hand sensor to fail intermittently.

 

METALS AND PAINT

 

I’ve never liked paint. Probably it’s because the first job I was given when starting at Magnadove, (the industrial modelmakers I worked for after leaving college) was to paint their sign board. I spent two weeks painting and sanding the background white colour, every time being told to start again – when I started I’d no idea it was possible to get a hand painted surface completely flat and shiny like a sprayed one…and by the time I’d finished, it was really flat and shiny, but I never wanted to paint anything ever again. 
But I also dislike paint because it looks great when its new, but then just gradually looks worse and worse. To me, paint is usually a bad option when there are so many surfaces which improve with age – wood, most exposed metal and even some plastics. Surfaces which wear gracefully, like the metal on my southwold pier  clock on  are always more practical and more appealing than those which deteriorate ungracefully. 

So I decided to do without paint on this clock. The alternatives – anodising and electroplating, both involved chemistry, and I enjoy messing about with chemicals.  Particularly industrial chemistry which avoids the disappointment of so much school chemistry! Industrial chemistry is chemistry that has been proved to work. It still involves a lot of trial and error, but the results are never unobtainable. Industrial processes never catch on if they aren’t reliable and easily reproducible. 

Finding out about specialist techniques like anodising and electroplating would have been tricky in the past. The boss of my local electroplating company is certainly not the type to encourage DIY forays into his territory. But this is where the internet is so fabulous. For every speciality, however obscure, there is an enthusiastic expert. I bought an anodising kit from a man in Wisconsin, a gold plating kit from a man in Bath (England) and sent ‘Mr Titanium’ from New Mexico a donation for his site, as it described the process of anodising titanium so clearly.  Experts like this assume their customers are enthusiastic amateurs like me. The kits were great fun to try, and the experts all responded enthusiastically whenever I had problems. The processes I used also shared a surprising amount. The electroplating power supply was also perfect for anodising the aluminium. The giant vat of sulphuric acid for anodising the aluminium was also perfect for pickling the copper prior to electroplating. Chemistry is such a great subject, its baffling to me that it is possible to make it quite so dull at school.


Prototype anodised titanium wing. 
No dyes, just painting with electricity 

I hadn’t imagined the birds ending up so bright and intensely coloured but the processes were so successful they just seemed to make everything bright. Fortunately I’d just been to zoo on a really dark winter’s day. Everything looked grey, except for the parrots. Their colours looked even brighter in comparison with everything around them. So bright seemed right. 

 

ZOOS

 I’ve wanted to make something for a zoo for a while. I really enjoy looking at animals, they are astonishing to see in the flesh, so different from any photo or nature film. On one trip to London Zoo as a child, a tiger pissed on my cousin Nicola – the volume and force was amazing, like a fire hose, and she smelt of tiger all day. Nothing on TV can compete with experiences like this. However, I was increasingly told that zoos were cruel places and that animals shouldn’t be kept in cages. I still sometimes feel this when I see an animal restlessly pacing. I don’t like London Zoo’s new gorilla enclosure because the gorillas still look so sad, though that maybe me anthropomorphising their normal expression. But as I’ve read more about zoos, I now feel the anti zoo position is narrow minded. The books and papers use exactly the same phrases, like some sort of party political line. Nowhere does it really address the fact that we are ‘naked apes’, members of the animal kingdom, and that mutual curiosity and interaction are ‘natural’, even if unequal. 

 


The tiger is actually behind thick glass

Zoos have greatly improved since my childhood. Cages have largely disappeared, replaced by more subtle barriers like moats and electric fences. I’m not sure this makes any difference to the animals, but it certainly does help visitors feel less guilty. Zoos have got better at selecting species that thrive in captivity. I spent a day drawing a bunch of squirrel monkeys a couple of years ago. They have such a busy social life, with parents, grandparents, children, delinquent teenagers, their life appears to be a manic soap opera, certainly not lacking in stimulus. Then the keepers now often talk to the public. It’s really interesting finding out about the individual animals from the person who looks after them.  Watching the penguin feeding time at London zoo was hysterical because several penguins were more interested in cuddling up to the keeper than grabbing the fish. She explained this was because they had been hand-reared, and she then revealed why the penguins had been moved out of Lubetkin’s 1930s grade one listed concrete enclosure to an ordinary looking pond. The poor birds had been developing arthritis from walking on concrete all day. (I’m not sure any architecture so completely unfit for purpose be grade one listed but this is a digression.) 

Zoos also now stress their importance in conservation. The number of animal species in danger is certainly scary. Not everyone believes zoos are any help – they say the gene pool in zoos can never be large enough for a species to survive exclusively in zoos. But even if this is true, zoos now champion their role in education, showing us wonderful and extraordinary animals to encourage us to care about their survival in the wild. Sometimes this comes across as too worthy for my taste, but the older I get, the animals themselves just seem more and more astonishing and worth preserving.  

The disapproval of UK zoos in the last few decades may have been a great asset. They have been starved of cash and so have avoided the numbing bureauocracy of worthy institutions like the London Science Museum. Zoos, like seaside piers, have miraculously managed to avoid becoming part of ‘culture’. People of any age or background go to them with no pretentions, zoos are just instinctively enjoyable. 

A painter I met recently described his problem with culture, or more precisely cultural institutions. He enjoyed working in unlikely places, observing and drawing everything happening around him (which I entirely sympathise with). He said that seeing his finished paintings in an art gallery always felt disappointing. His rich experiences lost their power when transported into the tasteful white environment. Maybe culture has been captured by bureaucrats so its now all presented in standard formats. Perhaps the root of the problem is that there’s so much ‘culture’ now that most of what’s in art galleries just isn’t very good. Then culture can also be a form of snobbishness. Anyway, whatever the reason, personally I just feel happier working in places like piers, hospitals and zoos.     


19th century travelling menagerie

Zoos are far more ancient than museums or art galleries. The Pharos had collections of exotic animals. London Zoo started as the king’s collection of animals, on public display at the Tower of London. In the 18th and 19th centuries zoos were often part of ‘pleasure gardens’ and travelling menageries often featured at street fairs. The animals were badly treated so things had to change, but today zoo animals are well treated, and I suspect the popular delight in watching animals may be returning. Particularly because more and more stuff is digital and virtual, experiencing real stuff is becoming more and more special. My clock was commissioned because it fitted the zoo’s education aspirations, but I also hope it also celebrates a return to zoo’s showmanship and sense of fun that was part of the 18th century pleasure gardens.

 

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