How modern touchscreens meet the challenges of the outdoors

Shining brightly through thick and thin

Sweltering heat in the Rhine Valley, the infamous Siberian cold in Berlin, autumn storms in the Münster region, classic foul weather in Hamburg – parking meters and ticketing machines have to withstand the very worst central European weather has to offer. If you want to avoid queues of frustrated customers trying to pay for their parking tickets in vain, these machines have to be durable and function without a hitch every time. In the process of implementing these requirements, the Hamburg company Garz & Fricke supplies the automated systems manufacturer bebarmatic with reliable display solutions and embedded systems – increasingly connected with digital spheres.

The Duisburg firm bebarmatic specialises in parking systems. Especially the requisite vending machines, are part of a driver’s everyday life. And every driver knows how annoying it is when the machine fails and you have to dash miles through the pouring rain to find the next one. This is why reliability is one of the absolute musts in vending machine technology. ‘Our systems have to be able to withstand not only damp and warmth but also extreme cold,’ says bebarmatic’s Elmar Schulte-Herweling. ‘Especially the highly-sentitive touchscreen is a real challenge.’ The touch display has to surmount several difficulties at once. It is open to the elements and has to be suitably robust whilst still being easy to read and sensitive to all input.

At first glance, you might think a thick pane of glass would do the job, but it is not as easy as that. ‘Thick panes’ and ‘on-target operation’ are uneasy bedfellows because the light gets refracted in thick glass. This so-called parallax means that it is harder for the user to hit the various operating elements on the screen. Moreover, sensitivity suffers when the pane is thicker. Garz & Fricke GmbH in Hamburg can deliver the optimum compromise in various different price categories in accordance with requirements.

Addressing the challenges

Manfred Garz

"With the really expensive displays, every application can be mastered. But it just goes beyond the scope of what the finished device may actually cost."

Engineer and CEO Manfred Garz

Resistive or capacitive

In addition to the display technology, customers can also make choices about ‘touch’. The touch- sensitive surface either functions on the principle of a resistive or a capacitive touchscreen. As a rule, resistive technology has the advantage that it is optically more attractive, can easily be operated with gloves on, and is not susceptible to electromagnetic interference. The high level of brightness also speaks in its favour. Monitors of this kind are, however, very susceptible to damage by vandals. Even a simple cigarette lighter can easily damage the plastic surface. And somewhat poorer light transmission and readability in sunlight also speak against resistive touchscreens in carparks.

The capacitive touchscreen, by contrast, is positively finger-friendly and yet very robust. It is designed for input with a bare finger and even recognises the input of several fingers at the same time – known as multi-touch – for example, gestures. When a finger touches a capacitive touch surface, low currents flow which enable the electronics to determine the position of one or more fingers. Capacitive technology does, however, present developers with some knotty problems, especially outdoors. Unlike the resistive touch, input here can be disrupted by rain drops because in terms of functionality, a droplet of water has the same effect on the screen as a finger – both control the current. Without additional measures, the system cannot tell them apart.

Touch Screen

Special software adaptations ensure that the touchscreen works just as well in the rain as in the dry.

Manfred Garz

"The display, which is sturdy, finger-operated and also susceptible to, for example, drops of water, is not there yet."

Manfred Garz

Scorching heat

Manfred Garz

"The temperatures in a ticket machine or cash machine can quickly rise to well over 60 ° C - a test for the built-in electronics, which heats up under these conditions."

Manfred Garz

High performance at low power consumption

Tailored to the case

Garz & Fricke supplies ready-to-install components for its customers’ casings. Depending on customers’ wishes, coin validators and electronic payment systems can also be connected.

Equipped for the future

Open and competent

"We wanted finished components and we found them at Garz & Fricke. And, on top of this, excellent technical expertise"

Elmar Schulte-Herweling - bebarmatic