If you want to effectively develop an HMI, you are faced with a complex development process with many potential pitfalls. A well-thought-out HMI 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 device 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 HMI has to achieve in daily use.
Questions that should be asked early on:
> What environment is the device used in (indoor, outdoor, industrial environment)?
> Is the device operated with gloves, in damp conditions or with disinfectants?
> Which protection classes (e.g. IP65) or quality 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 HMI 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 switches 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 develop an input device 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.
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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.
Effectively developing an HMI – that involves a design combining aesthetics and functionality. The choice of material must match the application: While chemical-resistant overlays are required for medical devices, a hardened glass with anti-glare coating for better readability in bright light can be decisive in industrial applications.
Lighting is also an important aspect: uniform backlighting of symbols and buttons not only increases intuitive usability 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: 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 overlays 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 switches, unsuitable materials or insufficient installation space for the necessary electronics can make subsequent modifications expensive.
4. Consider integration into the overall system
HMIs 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 HMI 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 keypads 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 HMI 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 HMI 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 HMI or redesign? Make an appointment with our HMI experts – we will support you from the initial idea through to successful series implementation.
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