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EVTEK University of Applied Science
Accessibility in Embedded Systems
Esa Häkkinen
TP02S
16.9.2005
1 Introduction
In modern electronics, more devices are made using embedded intelligence every day. Coffee
machines, vacuum cleaners, air conditioning, mobile phones… They all are today cheaper to make
with one microcontroller. What can a engineers do to make it easier to use these devices?
The common way of thinking about accessibility is originated at least 1700th century. As people
were thinking, there are only normal healthy people with almost a Spartan body and brilliant
personality, or man is weak because God cursed him and Evils are in his body making them sick.
This way of thinking is still present in our society, we really still think that there is normal and then
there are these other people. Even commercial marketing today makes assumption that individuals
are dumb, and by turning an easy thing complicated and giving out a easy solution, they make more
profits out from it.
In 2001, World Health Organization WHO made a new terminology suggestion, which would
change the common definition and a new way of thinking: let’s not just separate humans into two
different groups, let’s just think that every human has different amount of abilities and they
sometimes don’t reach society’s demands [Zato, WHO].
Accessibility is already taken part of a design processes, but only in sense of system availability
against 99,999% of time. We really could make new embedded device’s user interface easier to use,
just by lowering the demands against user’s abilities. Maybe these devices must be usable even in
emergency situation, like stopping air conditioning system during a fire or making a call help with a
mobile phone a little bit easier.
How could this new model of thinking make electronics easier to use today? Should we change
something in developing of a intelligent embedded system process? In which part of this process we
should be make a little effort, to make our final product a bit easier to use without a heavy manual?
2
Common Problems in embedded systems
2.1 Logic of User Interface
Symbols and logic of a embedded system are usually considered hard to learn. Usually limiting the
number of buttons on one cross-hair and one OK is enough, if there is a display for menu structure.
Sometimes a more simple interface is needed, like only On/Off and speed control, but still those
could be done with only one button, where longer is different than short impulse, which isn’t
usually clear for first-time users with manual lost somewhere.
2.2 Location of the control interface
Why there are vacuum cleaners with speed control in the handle? Users usually don’t want to climb
on ladders toward ceiling to turn on the lights; the control switches can be located into walls nearby
exits. But in embedded systems, there is no remote control in mobile phones; the control interface
must remain in exterior of the device.
2.3 Nature is brutal on embedded devices
Since embedded device should usually be small and it must survive from winter and rain, resist
huge humidity and sunshine effects in electronics, their designing is problematic. But solutions are
still quite cheap, like a metal case, but it might be too heavy to carry along. Plastic looses flexibility
in sunshine, but adding a ultraviolet resistive chemicals might cause health concerns.
2.4 Price tag effects
This is the reason, why coffee makers have microcontroller inside – it is cheaper to control only one
heater resistor with microcontroller, than use two heat relays, which makes it one dollar cheaper to
manufacture. Usually, there are marketing demands to separate the product from grey mass by
adding a fancy-looking coffee concentration control knob outside and two hour safety power-off?
So there already is software inside embedded systems, why couldn’t we program the user interface
easier to use, even for impaired people?
3 Designing with accessibility as one goal
Designers should have vision on the final device before they start sketching electronics. They
should already know something about different human perception levels, even unique person might
be ill or in a hurry sometimes, and he cannot concentrate his thoughts on the temperature control of
air conditioning.
Usability engineering is already a part of big embedded device companies, like Nokia, development
unit’s tasks. They already think what can a healthy two-handed ten-fingered sharp-vision strong and
cleaver happy end-user do think about these interfaces, but they really don’t spend time on thinking,
how hard this user interface might be for the person, who has been impaired or have lower
perception level.
It isn’t obvious, that more accessible design wouldn’t be kept beautiful and desired by end-users.
Maybe normal humans could appreciate easier interfaces and larger font on the displays, if the
devices are made looking visually good and steady to handle even with greasy hands.
4 R&D should hear after-marketing feedback
Most of the elevator companies are getting the big moneys after selling the actual system. They are
really listening the customers and carry out the feedback to the research&development department.
When individual end-users are heard and their ideas are token in use, we might end up with easier
devices out from the packet.
The Rank Xerox have had a huge problem ten years already: they can not find people, who haven’t
used a computer, to their user interface design laboratories. Maybe this lack can be covered with
taking impaired or less perception people to help research new ideas and fixing current ones.
Sources
[Zato]
Zato, Jose G. Introduction to assistive technologies. 2005.
[WHO]
World Health Organization WHO. Internet pages http://www.who.org.