engineer

tim   .

                                                      


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.   hunkin

                                                         


cartoonist

 

2 TON SCHOOL RUN

I wasn’t sure if the initial idea for this machine would work out. I feared it might turn out either too childish or cause too much ‘offence’. But an initial idea is only ever a starting point, it’s the process of turning it into a physical reality that’s always the interesting part. During the process, ideas always change. At the time I’d been experimenting with possible ingredients for future machines when this road crash mechanism worked much better than I expected.

 

First prototype video

The theme came from my weekly visits to my mum, who lives in a posh suburb of London with a school at the end of the road. The chaos at the end of the school day with so many badly parked huge cars and the tiny children in their mum’s enormous Chelsea Tractors (SUVs) often made me laugh. The cars are the parents’ battle tanks for protecting their children. In this respect they work well – a recent survey found that collisions between large heavy cars and small light ones resulted in the occupants of the small cars 12 times more likely to die. Though socially unjust, its also true that road deaths generally have fallen massively over the last 50 years so everyone is safer than the used to be.

Then as an engineer, I’m astonished that these enormous vehicles weighing around 2 tons, with the fully electric ones weighing even more, can be considered ‘green’. The amount of energy consumed by a car is roughly proportional to its weight. While its fashionable to think that electric cars are the future I’m not convinced the current generation are even as green as a 1950s Citroen 2CV. Weighing four times less, it could do 60mpg and with modern efficient petrol engine could do double that.

 

Second prototype video

The technical challenges of making the arcade machine interested me. Its always hard when parts physically bump into each other to find good ways to prevent them destroying each other or jamming the machine. They have to physically make contact or the game is no longer fun. So for a couple of months I carried on propelled by the challenge to see if it was possible, still doubting the initial idea. The covid lockdown had just happened so there were no distractions. I discovered several things that encouraged me to persevere. To my surprise, the crash mechanism worked even better with the car above the pivot point, balanced by a spring. Then realising that the paint on the car and the obstacles would get ruined by the constant collisions, I found that the car could hover 25mm above the road while still looking OK, and also that I could protect the obstacles with 2mm carbon fibre rods which didn’t look too visually distracting. (The rods came from Rex’s workshop, I’ve no idea what he used them for but I’m sure he would be delighted to know they had found a good use).

 

I then started carving the little wooden characters for the scenes. I enjoy carving and this was a smaller scale than I’d tried before, which was interesting. I realised the magic I felt about the first rough prototype came partly from my childhood memory of the 1930s Wonder Book series, of which we had many. What I most loved were the fly leaves at the beginning and end of the books. At the start would be an elaborate cartoon scene of people doing things, and at the end was the same scene with every element transformed into chaos. When I made my book of cartoons (Almost Everything There Is To Know) in 1987, I had the chance to do my own version. This prototype seemed a mechanical version of the same idea.

I was also thinking of Buster Keaton. Awful stuff happens but he always carries on oblivious. I wanted my accidents to be, as Buster Keaton called them ‘prat falls’, cartoon-like rather than bloody. When Bill and I finally fixed all the painted scenes into the machine they had charm. The accidents had the gleeful anarchy I was hoping for though maybe some people will still ‘take offence’. Children are now so shielded from stuff like this but maybe exposure to some politically incorrect ideas are a useful balance. I also recently read that for artists to ‘get on’ in the art world, they now have to subscribe to current politically correct ideas - so it felt good to be going in the opposite direction.

So as I worked the machine became as much a general celebration of irreverence as a satire of SUVs and their owners. It touched my constant amazement at today's risk averse mentality and sensitivity about causing offence - so different from the 1960s and 70s counterculture of my youth. I was never a hippy but loved the opportunities offered by the breaking down of barriers. The counterculture was so energetic and creative, and gave birth to lots of technology (particularly the personal computer). For me it was particularly the ending of closed shop unions which enabled me to make films and create museum galleries. It was a brief period of freedom, long since extinguished by today’s mind numbing bureaucracy.

This change was amazingly similar to the historical transformation during the early 19th century. My favourite period of history is the late 18th century, the so-called ‘enlightenment’. It was a time of fearless experimentation and excitement about technology, the start of the Industrial Revolution. By the mid 19th century, this had been replaced by conventional stuffy Victorian values. At the time the Victorians felt they were morally superior. They felt the Georgians of the 18th century were crude and unsophisticated. In some ways they were right. Passing laws to protect animals and children at work and end slavery were definitely progress. But the sparks of open-ended discovery, innovation and entrepreneurship suffered. The enlightenment started the industrial revolution, but by 1850 Britain was no longer the workshop of the world.

Anyway, returning to the '2 Ton School Run', my initial idea was that you would have answer the kids questions while driving but once the machine was playable, it was obvious that the real fun was trying to hit everything rather than avoid them. It had never occurred to me before that most games are about hitting targets rather than missing them. It’s uncomfortably similar to a notorious 1980s video game called Death Race where you had to mow down as many pedestrians as possible, turning them into tombstones. Wikipedia’s entry on controversial games is fascinating, but also to me depressing. As the decades have passed, people have objected to more and more subtle details of games.

As the machine neared completion, I tried many different variations for the verbal instructions but they basically were all either moralistic – “you have no idea of the destructive power of your SUV so now’s the time to find out”, or anarchic – “Your kids are safely in school so now you can go wild”. I don’t know why I dithered for so long, the moralistic ones just felt fake.

As I write, its been on the pier a couple of weeks and I haven't seen anyone hesitate to flatten everything in the car's path. I've often heard parents and grandparents encouraging their children to hit everything. I obviously had no need to so anxious about it and now I'm annoyed at myself for allowing today's 'fear of causing offence culture' to get to me. I suspect people who think like this are a tiny minority but their views have been amplified by the media. 

 

 

 

TECHNICAL DETAILS

The hardest part of making the machine was working out how to detect every collision.

The obvious way to do this would be to have a software ‘map’ of the road, with specific locations tagged as collision points. Unfortunately, though possible, this is clunky using my PLC controllers. But I also found that the position encoding sensors got out of step after a few collisions. A simpler more robust system is to use contact sensors on the car. My previous machine ‘Celeb’ works in this way. However making the sensors sensitive enough to a hit at any point round the car and also proof against false readings was so hard I eventually gave up. What worked best in this case was a combination of 2 systems.

First, when the car touches an obstacle it tips the section of road enough to trigger a switch which powers the road section to fully rotate and reveal the flattened version of the scene.

If for some reason this fails, or the car hits the side of an obstacle rather than head on the second system is activated. Both horizontal and vertical movements have encoders. Also the motors are belt drive, so the torque can be adjusted by the tension of the belt. The PLC simply detects if a motor is powered but the encoder isn’t registering any movement, and then reverses the relevant motor for a second or two.

At the end of August about 800 people had used it and so far it seems to be working fine, though I've had to adjust the torque limiter on the vertical drive a couple of times.

 

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