Danijel Kurinčič

Touch-screen interfaces for a car A/C service machine.

Beginning with the user research, understanding thoroughly the marketing approach and the business agenda for the product, we could come up with interface model that sets the standard for the client - and hopefully for the industry.
Client: Gorenje Design Studio (contact: Ana Osredkar) for AVL Ditest

The challenge: design market leading interfaces

A/C service machines need interfaces? Oh yes they do. The A/C service machines market is saturated with a couple of leading players, but still a profitable business for service shops. Even though the process of charging A/C units has become fully automatic, there still exists a certain peculiarity resolving errors and diagnosing system failures. Following their commitment toward building user friendly and modern devices, the AVL Ditest approached us with a challenge to design interfaces for their A/C service machine.

User research

The first step of the project was gaining a thorough understanding of the current customer behavior patterns. We interviewed 7 repair shop technicians about how they operate their A/C machines and other machines with touch screens. We quickly realised that speed means money and the progress must be clearly visible, many features of current machines are ignored, customers are often present while the process is under way, there are many resistive touch screens already in workshops, but also a lot of dirt and grease.

The output of this phase was a research paper with 4 design guidelines and other design considerations.

Understanding the product from the technical and sales points of view

Where the user interviews have left us puzzled, the 2-day visit to the clients production site has enlightened us and answered all the peculiarities of the numerous use cases. After that, we conducted a quick workshop for the product sales team. Following a known design thinking method we made two teams of sales people to each come up with a "product box" and try to sell it to the other team. This way, we could capture the debate and understand how the sales team wants to sell the product and thus which features are the most important.

Layout and core flows

The next step was wireframes. Understanding the product from the user, technical and business perspective really helped us to come up with the first version of the wireframes fast. At this stage the biggest challenge was coming up with a layout that would support the most common use case, as well as allow for use of advanced functions.

Designing for touchscreens

Builidng upon the technical knowledge of the GDS technicians, we assisted the client at picking the right screen and made sure we understand the consequences of the touch-screen techologies (capacitive vs resistive) for the design.
Aside technical limitations, we had to design the interface around the complexities of the numerous functions and settings of the machine. Once we had the main navigation and the core flow in place, however, this task was easier.

Due to the environment the machine is used in, we consistently took into account the two modes of operandi: from afar and from close. Some information had to be clearly visible from the distance of the vehicle, while other supported tasks close to the machine.

Emulating analog

Pressure of the system is very important for both regular use as well as for advanced "debugging" use. To enable technicians to feel "at home" with the new device and keep traditional information interfaces but at the same time build upon the digital, we have come up with big digital gauges. These enable users to quickly glance at the pressure rates and notice the possible sudden changes of the pressure. We have showcased the latter with some digital gauges prototypes as well (like this and this).


After a number of revisions we have confirmed the final interactions design as well as the final grahpical design (Katja Korinsek). Throughout the process the up-to-date wireframes were available as a clickable prototype, while the final graphical design was presented on the final presentation that delighted the client.

First impression of the device – the customers are overwhelmed! Very good feedback from the product managers and the customers from the fair in Frankfurt (Automechanika)! It seems that we did a very good job at all until now!
Dominik Heschl, Development Engineer Firmware

Final screens and a picture of the device