Game pad joysticks are probably without doubt physically robust enough to
take a considerable degree of punishment. What is less certain however is
the quality of their electrical switching or resistive elements.
If you are unable to defeat THARG because your joystick is a bit dicky in
the North-East quadrant, well you can go and by a new joystick and have
another go.
Depending on the application, if a wheelchair joystick suddenly becomes
unresponsive, or worse begins to drive on it's own, - that could represent a
serious hazard to a vulnerable client. Whilst recognising that the benefits
sometimes outweigh the risks, I am always reminded who might get torn to
pieces in a court of law should something go horribly wrong.
BSEN 12184:1999, ( Electrically powered wheelchairs, scooters and their
chargers - Requirements and test methods), Section 8.3 - gives instruction
on how to test "Control input devices" for electrical and mechanical
longevity. The standard also includes general wheelchair mechanical and
electrical construction standards, and specific test methods for EMC.
Coupled with documentation to the requirements of the Medical Devices
Directive, custom solutions can be made as safe as is "reasonably
practical".
Best regards,
Geoff
G.J.Harbach I.Eng MIED IIPEM
Clinical Technologist
Special Controls Service Manager
West Midlands Rehabilitation Centre
91 Oak Tree Lane, Selly Oak
Birmingham, West Midlands, B92 6JA
Tel 0121 627 1627 Ext. 53238
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-----Original Message-----
From: John Shermer [SMTP:[log in to unmask]]
Sent: 15 April 2003 18:22
To: [log in to unmask]
Subject: Re: Small joysticks[Scanned]
absolutely !
what is the point of companies spending large sums of money ensuring
systems are safe and meet the regulations if others are simply going to
bypass the rules and potentially put people at risk. I understand the
temptations to mend and make do or even come up with a 'clever '' and cheap
way of achieving something for a client. but ultimately it isn't clever at
all, a more relevant route is to make the companies aware of the problems
and seek proper solutions that are safe and can be replicated and supported
for years to come. the industry already suffers from poorly conceived
products that are poorly made. by making specific demands (and then buying
the results when they are made!) is by far the best way in the long term.
John Shermer
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