Why HMI development in Pro AV requires more than good interface design

When developing a new control interface for Pro AV or broadcast equipment, it is easy to focus first on what the user sees. The screen, control layout and visual design are obvious parts of the experience.

Modern control surfaces are much more than displays surrounded by hardware. They can combine touch, tactile feedback, programmable controls, embedded processing, firmware, control software and mechanical design within one interaction system.

Every decision made in one area can affect another. Display selection can influence enclosure depth, power requirements and thermal design. A rotary control can affect tooling, assembly and firmware. Moving functions onto a configurable touchscreen can reduce physical controls, but it also changes the software architecture and operator workflow.

This is why HMI development requires an end-to-end approach.

For broadcast and Pro AV manufacturers, bringing hardware, software and UX development together can reduce integration problems and create control surfaces designed around the way operators use them. It also creates opportunities to replace fixed hardware architectures with more flexible, software-defined interfaces that can evolve across products and workflows.

What does end-to-end HMI development mean?

End-to-end HMI development brings the main parts of a Human-Machine Interface into a coordinated development process.

Depending on the product, this can include the display, touchscreen, tactile controls, embedded computing, control electronics, firmware, software, mechanical engineering, industrial design and UX.

The objective is to develop these elements as parts of the same system.

A control surface may look straightforward from the outside, but the user interaction depends on several technologies working together. Pressing a button or moving a rotary may trigger firmware, update information on a display, send a command to another device and change the state of the interface.

Decisions about the UX therefore have consequences for both hardware and software.

An end-to-end development process considers those relationships earlier, before individual components and systems become difficult or expensive to change.

Why interface design alone is not enough

A visually clear interface is an important part of HMI design, but it cannot solve problems created elsewhere in the system.

Consider a broadcast control surface with a well-designed touchscreen interface. If operators need to look directly at the screen to confirm every input, it may become difficult to use while they are simultaneously monitoring a live production.

Adding physical or haptic feedback could improve the interaction, but that decision affects more than the UX. It may change the mechanical design, electronics, firmware and manufacturing process.

The same applies to other design choices.

Changing the display can affect enclosure dimensions. Introducing a new rotary control can alter tooling requirements. Moving functions from fixed buttons into software can reduce the number of physical components while increasing the importance of the software and embedded processing platform.

This makes the complete HMI architecture part of the user experience.

Start with the operator workflow

HMI development should begin with an understanding of what the operator needs to do.

Broadcast and Pro AV environments can place significant demands on operators. They may be monitoring several sources of information, responding to events in real time and adjusting controls while concentrating on something away from the interface.

The development team needs to identify which information requires constant visibility, which controls need immediate access and which interactions benefit from physical feedback.

This can determine where a touchscreen works well and where buttons, rotary controls, faders or haptic feedback may provide a better interaction.

There is research supporting the use of tactile information when attention is divided. A Human Factors study examining visual and tactile cues found that informative peripheral cues could support task switching and interruption management in environments with competing task demands. The research provides useful evidence for designing interfaces around limited operator attention.

The goal is not to add tactile controls everywhere. It is to understand which interactions benefit from them.

Combining touch and tactile controls

Touchscreens give HMI designers considerable flexibility. Controls can change according to the workflow, and one display can support several interface states without requiring additional physical hardware.

Physical controls provide different benefits.

A rotary encoder gives an operator something they can physically manipulate. A button provides a clear press action. A tactile fader can support precise continuous adjustment.

Hybrid interfaces combine these characteristics.

Densitron's Tactila® tactile technologies include touchscreen interaction, buttons, haptic feedback, rotary knobs and tactile faders. These technologies can be integrated into displays and control surfaces according to the requirements of the application.

Tactila® rotary controls can also be incorporated into touchscreen interfaces without drilling through the front glass. The control can change function through software, allowing a single physical input to perform different tasks as the interface changes.

This creates opportunities to reduce fixed hardware while retaining physical interaction.

How software-defined controls change HMI development

Traditional Pro AV control panels often use fixed mechanical controls. Each button, knob or switch has a defined function, and changing the product can require changes to the physical front panel.

Software-defined interfaces create a different architecture.

The function of a control can change according to the current workflow, application or UI state. A rotary control might adjust one parameter on one screen and perform another function when the interface changes.

Touchscreens can expose controls only when they are required. Software can also allow similar hardware platforms to support different products or configurations.

For OEMs, this can reduce the need to develop a new physical control layout for every product variant.

Densitron's current broadcast and Pro AV HMI platform combines programmable tactile interaction with multi-touch displays, embedded processing and configurable UI behaviour.

This approach allows more of the interface to evolve through software rather than repeated mechanical redesign.

Reducing hardware and BOM complexity

Every physical component added to a control surface has implications beyond its immediate function.

Buttons, rotaries, switches and other controls need space, electronics, mechanical integration and assembly. Different product variants can require different front panels, tooling and component inventories.

A more programmable HMI can reduce some of this complexity.

If a single tactile control can perform several functions according to the current UI state, fewer dedicated controls may be required. If products can share the same underlying display and control architecture, OEMs may also be able to reduce the number of hardware variants they need to develop and manage.

This does not mean removing physical controls wherever possible. The aim is to use fixed hardware where it supports the workflow and software-defined interaction where greater flexibility is useful.

The resulting architecture can then be evaluated against usability, cost, manufacturing and product lifecycle requirements together.

Firmware needs to be part of the interface conversation

As HMIs become more programmable, firmware becomes an increasingly important part of the operator experience.

The firmware may determine how a tactile control behaves, how quickly the interface responds and what happens when the control changes function.

This means the physical and digital parts of the HMI cannot be developed independently.

A rotary may feel appropriate mechanically but still produce a poor interaction if its software response is slow or inconsistent. A haptic response may be technically functional but distracting if its timing or intensity does not match the action taking place.

Firmware development therefore needs to happen alongside hardware and UX decisions.

This becomes even more important when manufacturers want to reuse an HMI platform across several products. The underlying hardware can remain consistent while firmware and software configure different control behaviours for each application.

Connecting the HMI to the wider system

A professional control surface rarely operates alone.

Broadcast and Pro AV interfaces may need to communicate with multiple devices, applications and data sources. This requires a control layer capable of connecting the physical HMI with the wider operational environment.

Densitron's IDS control and integration platform provides this software layer.

IDS is vendor agnostic and can integrate with devices and applications through IP, I/O and APIs. It supports touchscreen and tactile operation and can centralise control across distributed systems.

This allows the HMI to become a point of control for a broader workflow rather than a standalone interface for one piece of equipment.

For broadcast environments in particular, this can be useful where operators need to interact with equipment and systems from multiple vendors through a consistent interface.

Mechanical engineering shapes the user experience

Mechanical design can sometimes be treated as something that happens after the interface has been developed. For an integrated HMI, it needs to be considered much earlier.

Screen dimensions affect the enclosure. Physical controls require appropriate spacing and mounting. Connectors and electronics need space behind the interface. Cooling requirements can affect the size and construction of the finished product.

The position of controls also influences usability.

A rotary placed too close to another component may be difficult to operate accurately. A touchscreen installed at an unsuitable angle can be harder to view or use. Controls that work well on a large prototype may become cramped when fitted into a rack-mounted unit.

These constraints need to feed back into UX decisions.

The finished HMI is a physical product, so its mechanical architecture and operator experience need to develop together.

Designing for manufacturing rather than the prototype

A successful prototype does not automatically result in a successful production product.

As the HMI moves towards manufacturing, teams need to consider tooling, assembly, component availability, testing and long-term reliability.

Highly customised hardware can provide differentiation, but it can also increase non-recurring engineering costs and manufacturing complexity. A design that uses established display and tactile platforms with configurable software may offer another route.

The appropriate balance depends on the product.

Some applications require a highly customised interface. Others can use an existing platform with selected changes to the display, controls, firmware or mechanical design.

Making this distinction early can prevent engineering teams from investing in bespoke elements that provide little benefit to the finished product.

Scaling an HMI across multiple product variants

Pro AV manufacturers often develop families of products rather than a single control surface.

An amplifier range, for example, may contain several models with different functions or capabilities. Traditionally, those differences could require separate front panels and control layouts.

Programmable HMIs can make it easier to share more of the underlying hardware.

The same display and tactile platform can potentially support different interface configurations through software. Controls can change function according to the product, and the UI can expose different features without requiring a completely different physical architecture.

This can help reduce the number of hardware variants across a product family while giving manufacturers room to differentiate individual models.

It can also make future product updates easier because more of the interface behaviour can be changed through software.

Who offers full HMI integration for broadcast control surfaces?

Densitron provides integrated HMI development for broadcast and Pro AV control surfaces, covering display technology, touchscreens, tactile controls, embedded processing, firmware, control software and custom interface development.

Its engineering teams support projects from concept through production, including interface architecture, firmware integration, prototyping and production support.

Densitron's Tactila® portfolio provides programmable tactile technologies, while IDS provides the software-driven control and integration layer. These can be combined with embedded displays, ProDeck desktop control surfaces and RU Series rack-mounted systems.

Densitron also develops fully customised control solutions for OEMs and integrators that require a control surface built around a particular workflow or product architecture.

This allows manufacturers to work with one HMI technology partner across several layers of the interface rather than sourcing the display, tactile controls and integration software separately.

Standard, configurable or fully custom?

One of the most useful decisions an OEM can make early in HMI development is determining what needs to be customised.

A fully bespoke control surface can be appropriate where the product requires a distinctive architecture or highly specialised workflow.

In other cases, a configurable platform can provide the required differentiation without developing every component again.

Densitron supports several levels of HMI development. Manufacturers can integrate individual display and tactile technologies into their own products, use configurable control platforms such as ProDeck and the RU Series, or develop a customised HMI around specific requirements.

This gives engineering teams the option to concentrate custom development on the areas that provide the greatest product or operator benefit.

Moving from HMI concept to production

An integrated development process connects the operator experience with the engineering required to manufacture it.

The workflow defines what operators need to see and control. That informs the display, touch and tactile architecture. Those choices influence the electronics, firmware and mechanical design. Prototyping then allows the complete interaction to be evaluated before the product moves further towards production.

Problems identified during this stage are generally easier to address than problems found after the mechanical design, electronics and software architecture have been finalised.

This is one of the main benefits of treating HMI development as a system rather than a collection of components.

Densitron's broadcast and Pro AV HMI development brings these technologies together, supporting manufacturers developing control surfaces for broadcast production, professional audio, live events and integrated AV environments.

Key takeaways

• End-to-end HMI development brings displays, touch, tactile controls, embedded processing, firmware, software and mechanical engineering into one development process.
• Software-defined tactile interfaces can reduce dependence on fixed hardware and support more flexible control architectures across product variants.
• UX decisions need to account for operator workflow as well as the engineering and manufacturing requirements of the finished control surface.
• Densitron provides integrated HMI technologies and development support for broadcast and Pro AV, including Tactila®, IDS, embedded displays and configurable control platforms.

Building the complete Pro AV control experience

Modern Pro AV and broadcast control surfaces increasingly combine physical interaction with configurable software.

That creates opportunities for OEMs to reduce fixed hardware, build more flexible product families and give operators interfaces suited to increasingly complex workflows. It also creates engineering dependencies that need to be addressed early.

Developing the display, tactile interaction, firmware, software and mechanical architecture together provides a clearer route between the initial operator requirement and a manufacturable control surface.

Densitron supports this process with integrated HMI technologies for broadcast and Pro AV, combining displays, tactile interaction, embedded processing and software-defined control with engineering support through development and production.

For OEMs developing a new control surface or replacing a fixed hardware architecture with a more programmable platform, Densitron can support the complete HMI rather than a single component of it.