When we talk about ergonomic design we refer to an optimized interface between “man and machine”. In the eSticky project, ergonomic design includes both the physical accessibility of the devices and the design of the user interface.
Furthermore, we must not forget that people with dementia have particular ergonomic needs. This is because the disease makes it difficult for those affected to learn new operating patterns.
In addition to the limitations of the disease, there are the general limitations of age. In particular, close attention should be paid to limitations such as vision, hearing and motor skills. That’s why the touch control elements of the eSticky are designed in such a way that their operation is immediately and intuitively recognizable. The color and shape of the operating element make it visually perceptible how it is pressed, turned or otherwise manipulated.
Now let’s see in detail what are the ergonomic requirements of the individual hardware elements of the eSticky project.
Ergonomic requirements of the individual eSticky hardware elements
To understand what are the specific requirements on the ergonomics of individual hardware elements, we must refer to the ISO 9241 Ergonomics of human-systems interaction standard.
When we talk about electronic devices, one of the most important parts is the screen. Below we see what are the ergonomic requirements that it must have:
- Screen size and format suitable for work activities;
- Simple to install, easy to rotate, height adjustable, tiltable;
- Image without flicker and distortion, smooth and stable;
- Good screen brightness and high contrast;
- High quality fonts;
- Crisp, clear and large enough fonts;
- Matte, non-glare surface and luminous body to avoid annoying reflections;
- GS Conformity Mark and TCO Seal of Approval – is internationally recognized for safety and sustainability and brings many competitive advantages.
For this last point it must be emphasized that the GS seal of approval (tested safety) in Germany is not mandatory, but brings an international competitive advantage. The seal of approval is obtained after:
- Electrical and mechanical safety tests;
- Functional safety tests, endurance tests and much more;
- Testing for chemicals and pollutants;
- Tests on ergonomic aspects;
- Measurement of noise emissions.
Finally, ISO 9241 Part 3 contains the following visual display requirements:
- Design viewing distance: angle of line of sight, point of view;
- Character height;
- Spacing between words: line spacing, linearity, display brightness;
- Luminance balance: glare, image polarity, luminance uniformity, luminance coding, flashing coding;
- Temporal instability (flicker);
- Spatial instability (jitter);
- Color of the image on the screen.
Feedback Button Requirements
Another very important hardware part is the so-called Feedback-Button, or feedback button.
Here are what are the design guidelines for button ergonomics:
- Adequacy: the input device should match the user, the user’s activities, and the user’s work;
- Operability: use should be predictable and consistent;
- Predictability: it should match the user’s expectations;
- Consistency: buttons should behave the same even when used in similar situations;
- User compatibility: the design should match the users’ capability;
- Feedback: the device should let the user know when it is responding to their actions;
- Controllability: the device should be responsive;
- Biomechanical load: it should be minimized.
ISO 9241 Part 4 contains the following topics related to the feedback button. First, the overall design of the keyboard and keys must include elements such as:
- visible key surfaces;
- keyboard slope;
- keyboard slope adjustment.
Key design covers such elements as:
- key layout;
- key displacement and force;
- typing feedback:
- bounce action;
- cursor keys;
- numeric keyboard;
- keyboard cover shape.
Principles of interaction
We discuss principles of interaction between a user and a system that are formulated in general terms, i.e., independent of usage situations, application, environment, or technology.
The ISO document provides a framework for the application of these interaction principles and general design recommendations for interactive systems:
- Task adequacy;
- Self-descriptiveness;
- Conformance to expectations;
- Learning facilitation;
- Controllability;
- Tolerance to errors;
- Customizability.
To learn more about this topic, we recommend reading the article User Stories: the process of primary and secondary user interaction with eSticky.
Ergonomic requirements: materials
Materials for the target group of people with dementia must have certain properties. In particular, the surfaces of the materials must therefore be glare-free. This may mean that a shiny material may not be suitable, although it provides good interaction with other materials. Therefore, devices should have a matte surface.
The tactile touch of the material is equally important to the user. It should give confidence through a secure grip. For this reason, the use of a soft, rubber-like plastic layer is recommended. This type of material allows for a better and more secure grip.
At the same time, a plastic material usually does not feel as valuable as, for example, a natural material. For this reason, natural materials are probably the best way to go.