If you want to plan an input system properly, you are faced with a complex development process with many pitfalls. A well thought-out input system is a crucial component of every modern device – whether in medical technology, mechanical engineering, mobile applications or food processing. This article shows what developers and product managers should pay attention to in order to save time, costs and nerves – and to develop an HMI system that is technically, functionally and economically convincing.
1. define requirements at an early stage
A common mistake in the early project phase is incomplete requirements elicitation. The focus is often on design or touch technology before it is clear what the input system has to achieve in daily use.
Questions that should be asked early on:
- In which environment is the device used (indoor, outdoor, industrial environment)?
- Does the system have to work with gloves, in damp conditions or with disinfectants?
- Which protection classes (e.g. IP65) or standards (e.g. IEC 60601 for medical technology) must be met?
Tip:
Involve all stakeholders – development, product management, quality management – as early as possible. Involve your planned partner for the implementation of the input system in order to benefit from their experience and clarify technical feasibility at an early stage.
2. clearly think through the operating concept and user guidance
The choice of HMI components should not be determined by trends, but by the operating concept. Capacitive touch, membrane keypads or hybrid systems – each technology has specific strengths. If, for example, haptic feedback is crucial (e.g. for machines in noisy environments), a pure touch solution is often unsuitable.
Planning error no. 1: Dynamic software interfaces on touchscreens, although operators need a fixed layout with tactile feedback.
In order to plan an input system correctly, a thorough analysis of user requirements is essential. Ergonomics, visual guidance, feedback and operating logic must be precisely tailored to the application context. A well thought-out operating concept not only reduces operating errors, but also increases efficiency and acceptance. Ideally, typical usage scenarios should be incorporated into the development as early as the concept phase – ideally in close cooperation with real users and the interdisciplinary project team.
Membrane keypad vs. touchscreen: Technical advantages in the industry
3. design is more than optics
Of course, the visual appearance plays an important role – especially with high-quality medical devices or modern mobility solutions. But good design takes far more than just color and shape into account.
Planning an input system correctly – that means creating an HMI design that combines aesthetics and functionality. The choice of material must match the application: While chemical-resistant front foils are required for medical devices, a hardened glass with anti-glare coating for better readability in bright light can be decisive in industry.
Lighting is also an important aspect: uniform illumination of symbols and buttons not only increases user-friendliness, but can also improve safety during operation. In mobile applications or outdoors, the display must also be easy to read in direct sunlight – a factor that is often underestimated.
Ergonomics is another key point in planning an input system correctly: Are controls equally accessible for right- and left-handed users? Can they be operated with gloves? Is the operating logic intuitive even under stress?
In summary, a good design also takes into account:
- Material selection (e.g. chemical-resistant front foils vs. scratch-resistant glass)
- Light guidance and legibility in direct sunlight or dark environments
- Ergonomics and usability, adapted to the user profile
Stumbling block: committing to a design too early without checking the technical feasibility. Tight bending radii for membrane keypads, unsuitable materials or insufficient installation space for the necessary electronics can make subsequent modifications expensive.
4. consider integration into the overall system
Input systems are not isolated components – they must fit perfectly into the device mechanically, electrically and functionally. If you think about integration too late, you risk regressions in the project plan or technical compromises in series production.
A frequent sticking point is the mechanical interface: just a few millimeters of deviation in installation cut-outs or fixing points can hinder installation or cause leaks. In applications with increased IP protection, sealing concepts must be carefully coordinated – also taking into account tolerances in series production.
Electrical integration is just as critical: How is the input system controlled? Which signals need to be transmitted – and via which interfaces? Is EMC conformity guaranteed?
There are also challenges on the software side: Drivers, firmware or operating logic must be adapted to the HMI. Especially in the case of customized keyboards or displays with special functions, it is advisable to network the development departments at an early stage.
Tip:
A common interface and installation concept, which is jointly coordinated by mechanics, electronics and software, prevents surprises later on – and speeds up product release.
5. from the prototype phase to series production: testing, testing, testing
As soon as an initial sample is available, the decisive phase begins: validation under real conditions. This is the only way to avoid expensive series errors later on. Typical weak points that only become apparent in the field:
- Insufficient durability of the surface with cleaning agents
- Unclear operating feedback
- Problems with operation under environmental influences
If you want to plan your input system properly, you should test it in this phase under realistic conditions – ideally with real users and in the intended environment. This makes it possible to realistically evaluate function, feel and durability and avoid complaints later on.
Conclusion: Good planning saves time, money and nerves
A successful input system does not come about by chance. It is the result of clear requirements, well thought-out operating concepts and close coordination between all those involved – from product management to series production. Investing in technical feasibility at an early stage and relying on experienced partners avoids expensive reworking in series production.
👉 Are you planning a new input system? Make an appointment with our HMI experts – we will support you from the initial idea through to successful series implementation.
