I have seen a number of people posting about the need for a dock for the R?.
The following article, offered for comment and criticism, is aimed primarily at educators, though it applies to all users, arguing for the use of a posturally-safe workstation with any sort of portable computer. With a heavy laptop, the engineering required to create a reliable dock connector is expensive. But the R? is so close in technology and size to a mobile phone that engineering a dock connector with the ‘dockability’ of an iPhone should be far less demanding.
Please could someone with the necessary skills try to engineer this with a beta board? If it works with leads brought from all the board's existing sockets, then one could only hope that a future version of the board with the dock connector riveted to the board should be fairly easy to produce. The sooner this can happen, the sooner docks can be developed. If the safety case isn't immediately obvious to you and you're interested, please read on.
When is computing potentially hazardous to learners' health?
There are many, oft-rehearsed arguments for providing learners with their own computers. Self-contained, portable computers such as laptops, netbooks and tablets possess the additional advantage of enabling learners to use the same software and data resources at home as well as at school. Furthermore, such self-contained portable computers are often highly attractive to educators, as, at the lower end of their price range, they are more affordable than a desktop or nettop computer workstation. They also take up less scarce space in classrooms and can be relatively easily moved between classrooms. Even quite low-powered devices can perform as remote desktop clients when connected to a network server that hosts applications and files.
For computers to be effective tools for learning, many factors need to be considered, such as affordability, standardisation, physical and data security, maintenance, teachers' access to relevant, timely training and expertise, and learners' e-safety. Less frequently considered is the question of how portable computers can be used in ways that avoid hazards to health such as neck pain, upper limb disorders (ULDs), including repetitive strain injury (RSI), and eyestrain.
Why does postural safety matter?
Employees who perform substantial work with computers in Great Britain are covered by the Health and Safety (Display Screen Equipment) Regulations 1992 (http://www.hse.gov.uk/msd/dse/
) published by the Health and Safety Executive (HSE) and designed to protect the health of people who work with all sorts of display screen equipment, including computers. Since learners in schools are not employees, they are not legally protected by these regulations.
However, if we are embracing the use of computers as tools for learning for a substantial proportion of the school day, we owe it to learners to enable them to use computers as safely at school as in the workplace, protecting them from distortions of posture (especially kyphosis, an excessive rounding of the upper spine) and excessive wear-and-tear of the intervertebral discs in the neck that are liable to cause them health problems in later life, informing them about safe practice in the workplace and making them aware of the risks they run if they choose to use computers less safely at home.
Principles of safe computer use
These may be summarised as:
Seating should provide adequate support for the user's back to remain relatively straight.
Seating height should be adjustable relative to the desk, so that the user's elbows are just above keyboard-level and their wrists are straight.
Screen height should be adjustable so that the centre of the screen is just below eye-level – anything lower than this encourages craning of the neck and hunching of the back.
Screen angle should be adjustable to optimise screen colour and contrast.
Natural and artificial light should be directed to minimise unwanted reflections from the desk and screen.
The potential hazards
Portable computers are suitable for occasional use, but are not ergonomically designed for sustained use. A standard laptop or netbook used by itself cannot conform with the principles listed above concerning keyboard and screen; the keyboard and screen are simply too close together for typing without bent wrists while viewing the screen with a healthy head and neck posture. See for example, the head and neck posture in http://www.ncl.ac.uk/gps/asset.....p_user.jpg
Similarly, using the virtual keyboard on the touchscreen of a tablet computer on a lap-stand or non-elevated table-stand will require excessive neck and risk flexion, as discussed in http://iospress.metapress.com/.....lltext.pdf
. Conformance with the relevant principles can only be achieved with a tablet computer or smartphone, if the device is used at eye level. Even the level shown in http://news.bbcimg.co.uk/media.....let624.jpg
is slightly too low. Clearly, sustaining such an arm posture for more than a few minutes would be very tiring and unsatisfactory for sustained work.
However good a room's lighting design is, all types of portable computer can easily be inadvertently placed in positions that produce unwanted reflections. While it is debatable whether a bean bag can ever support a healthy posture, it is highly unlikely that it can comply with the regulations when used as seating for a learner using a portable computer (http://static.guim.co.uk/sys-i.....-u-007.jpg
Mitigating the risks
The HSE's booklet The law on VDUs: An easy guide (http://www.hse.gov.uk/pubns/bo...../hsg90.htm
) states: “Whenever possible, users should be encouraged to use their portable at a docking station. Or, they can use the portable with a plug-in full-sized keyboard and mouse, enabling the height and position of the portable’s screen to be adjusted by placing it on raiser blocks.”
So a laptop, netbook or tablet can conform to the principles listed above concerning keyboard and screen, if the whole computer or detachable laptop screen is elevated on a stand that is adjustable to suit each hot-desking learner's height and used with external keyboard and pointing device. Alternatively, the portable computer can be attached to a separate, adjustable screen. The most convenient and least problematic way of connecting a laptop to a screen, keyboard and pointing device is to place it on a docking station to which these devices are attached. Unfortunately, laptops equipped with detachable screens or docking stations tend to be very expensive, partly because of the additional high-reliability connectors required and partly because of the relatively low volume of production.
So, notwithstanding the other potential advantages of using portable computers in the classroom, facilities for safe input and output during their sustained use require as much space and possibly even greater monetary expenditure than those required for a desktop or nettop computer.
An ultra-low-cost dockable, portable computer?
The Raspberry Pi is a credit-card sized, Linux computer based on a mobile phone processor. Harking back to the era of Sinclair ZX computers, it is not supplied with a display screen and relies on an external HDMI-compatible screen and loudspeakers, such as a domestic television, for output. The Raspberry Pi is available for as little as $35 (with Ethernet) because it is also supplied without any input devices.
So, the Raspberry Pi represents an extremely low-cost, “micro”, portable computer. Although some will no doubt use it as the heart of an ultra-low-cost netbook or tablet computer, educators probably need to concentrate on making it dockable with posturally-safe workstations.
The challenge exists for the Raspberry Pi project to engineer an open standard for a durable and easy-to-use dock connector, perhaps similar to that used on Apple media player, smartphone, and tablet products, for docking the computer with an adaptor that connects the computer to power, HDMI, USB hub for peripherals, and Ethernet at a workstation.