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BARGAINS
The materials I
use for making things have changed a lot since I started 40 years ago.
Through my teens and twenties there were wonderful industrial surplus
shops in London. After going into the Observer to deliver and edit my
cartoon strip, I would often fill my cycle panniers with beautifully
made motors, cam timers and other bargains from Lisle street or Edgware
Rd.
One by one the surplus shops closed, but for me their place
was taken in the mid 80s by the local scrapyards, particularly Sackers
of Ipswich, which received all the scrap from British Telecom research
labs. Complete machine tools, elaborate industrial automation machines,
endless entertaining boxes of mysterious electronics. My friend Rex used
to go to the scrapyard every day.
In their turn, the scrapyards closed down. (The price
of scrap steel virtually collapsed in the early nineties – which is
why scrap cars were so often burnt out and left by the road for a
while). Now, steel is so pricey cars are no longer abandoned. A friend
claimed in the winter of 2007-8 that he'd been offered £150 as scrap
value for a wreck.
Scrapyards are now so efficient and full of ingenious recycling
machinery that Rex and I are not allowed in when they're running.
But I'm now making a living by building contraptions instead of by drawing, so I
often buy new stuff,
especially from Radiospares. Here you can find a vast range of stuff –
with prices – order it – and have it the next day - without any oily
salesman calling round.
However, the cost of new industrial stuff soon mounts up, and doesn’t
have the appeal of using ‘free’ stuff. I started to look back on the
industrial surplus shops and scrapyards as some sort of golden age. Only gradually did I start to realise my error. We have entered a new,
completely different golden age of technological bargains – brand new
consumer electronics. Burglar alarm motion sensors for £9, boom boxes
for £20, DVD players for £40, PCs for £170, the list is endless.
This article is about the bargains I use in my museum
exhibits and simulator rides. Before I start I have to apologise for not
giving details of product models – they seem to change every 6 months,
so the ones I’ve used will already be unavailable by the time I finish
writing this. Don’t worry though, the changes are usually just
cosmetic – the underlying technology changes much more slowly.
MOTION SENSORING OUTDOOR LIGHTS
About £10. In place of the light, connect it to any other mains
operated device – disorientate burglars by switching on your lawnmower
or starting up a CD player (see below). Its also easy to change motion
sensors into beam sensors by sticking a tube on the front to make them
‘blinkered’.
WASHING MACHINE SOLONOID VALVES
At about £5, these are at least ten times cheaper than any other valve
of a similar flow rate. They work just as well with air as with liquid.
There are two slight drawbacks – first they need a bit of space (the
input and output connections are different and both quite clumsy and
bulky) – second, they won’t switch low pressures, which I often find
frustrating – but hard to grumble at the price.
CAR WINDSCREEN WIPER MOTORS
£5-£25 from a car scrapyard, £50-£70 new. Fantastically powerful,
long-lasting and quiet. I have one on my clock on Southwold pier which
has been switching on and off every one and a half seconds for over two
years – despite being in the salt air and nor waterproofed. DC motors
have an enormous starting torque, a huge speed range, simply adjusted by
the input voltage – 12 volt car wiper motors work slowly at three
volts but still have useful power and are completely silent. Use diodes
to reduce the speed (.7 volts per diode) - not resistors (Under load,
the motor has little resistance so the resistor just gets hot and the
motor doesn’t move).
BOOM BOXES
£20-£25 from most electrical shops. This is the cheapest way to buy a
CD mechanism, and it comes complete with ‘free’ mains adapter,
amplifier and speakers. I use them for the sounds on my exhibits,
connecting wires to the play and the skip forward buttons to switch them
remotely. (The cheapest boom boxes usually have the largest, most
straightforward switches so are easiest to wire up to.) I have had
problems with spikes making the remote switches erratic. The solution is
to have small signal relays or 4066 CMOS switches close to the player,
and keep the mains lead separate from the rest of the machine.
DVD PLAYERS
Down to about £40. I've just bought one and it plays everything, even
MP3s.
Anyway, they are certainly bargains for adding video
and sound to a contraption. Unlike VHS, these quite happily play 12
hours a day, every day, without losing quality, and have the enormous
advantage of changing tracks ‘instantaneously’.
I used to connect wires to the switches in the remote control, as this
meant the player was untouched, and could be easily swapped and returned
under warranty if it went wrong. However, this did not prove to be as
reliable as wiring directly to the buttons on the player.
The only problems with the really cheap players are they don't have many
buttons on the front so you usually would have to wire to the remote
control, (fiddly and not always reliable). The other problem is that
they are now so cheaply made they aren't lasting well. They are still a
good way to have a go at making a simulator, but mine are getting used
so much that I've had to change to using compact flash card kiosk video
players. These cost £165 but are really stable.
MEDIA
PLAYERS
I've been swopping my DVD players for compact flash card 'kiosk' media
players. No moving parts, so they should be generally more reliable.
However, my experience has been patchy. I used Grandtec's Eyezup for a
while, but they only have a next track option, so my PLC logic has to
send it the right number of pulses to address a particular track, and
this occasionally didn't work. So in 2006 I started using the Medeawiz
DV68 player. This usually goes to the right track, but occasionally
returns to track zero instead. My most reliable simulator is still
Quickfit, which is still runs MPEG1 on a 2002 Sharp DVD player (the
image quality is less important as the screen is further
away).
PERSONAL COMPUTERS
£170 from Europc. I was doubtful about the reliability of using a PC in
anything as my experience of Windows is that it is unpredictable.
However, Sarah Angliss used a PC for a Director movie in the gene
forecaster, which after the usual teething problems, has been quite
stable, running under windows 2000. I then tried one out in my
photobooth, running windows XP.
I thought I was going to have to learn some serious programming language
to get it to work, but eventually managed by simply recording sequences
of keystrokes in the Actions palette of Photoshop. I have then simply
wired the function keys (on the keyboard) to the booth’s master
controller. This is considerably more interactive than the
gene forecaster and had loads of teething problems. I've spent much more
time trying to make it stable than I did building the machine in the
first place. Its still not reliable, but the problems are now with the
printer and more electromechanical.
The future for stable applications obviously lies with Linux. Vista will
eventually become as stable as XP, but its even more insanely too
elaborate than XP for a computer that only ever runs one program and
never connects to the internet.
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