What is coming

The biggest lever on consumption is brightness, not the diagonal. A 55-inch indoor screen draws close to a hundred watts. The same device in a shop-window version at 2500 candela per square metre uses several times that, because the backlight does all the work. With LED walls, the picture content counts as well: a white surface uses considerably more than a dark image.

From that follow three adjustments that cost nothing but a setting:

Panels last longer than most people think. Manufacturers state 50,000 to 100,000 operating hours for the backlight before brightness has fallen by half. What reaches its end sooner is almost never the picture but the software: a device with a built-in player, an SoC device, eventually stops receiving updates.

That is why it pays, when buying, to look at separability. An external player can be swapped in five minutes while the display stays on the wall. Also ask about spare parts: power supply, mainboard, and for LED walls individual modules and receiver cards.

For the end of life, Switzerland has a clear system. Electrical devices are financed through the advance recycling fee and taken back by the SENS eRecycling and SWICO Recycling schemes. Return is free of charge, and dealers take devices back even without a new purchase. And consider a second life: a shop-window device that has grown too dim will still serve for years in a corridor.

What has changed is not the screen but the route to the page. It is useful where there used to be manual work:

Add voice control at kiosks. It makes sense where hands are full or hygiene matters, and it helps people who read a screen poorly. In a station concourse or a gym with music it stays awkward. Plan it as an addition to the touchscreen, never as a replacement. Our yardstick is simple: the machine may suggest, a person has to approve.

There are places where I deliberately switch off, and they have little to do with scepticism about technology.

Binding information does not belong in the hands of a machine. Prices, opening hours, allergens, emergency numbers, a municipality's deadlines: these values come from a checked source or from a person who stands behind them. Nor does uncontrolled generation belong on a public surface: whatever is created live has been read by nobody beforehand, and the screen in the window is a notice you are liable for.

The camera is delicate. Technically, age, gender or dwell time can be estimated. Legally you are then moving within the revised Data Protection Act, the nFADP, and practically within a question of trust. If at all, then with counting and no image storage, with a visible notice on the device, and with a purpose you can explain to a customer in one sentence. And one last point: no generated images of staff, rooms or products that do not exist in that form.

The clearest trend is unspectacular: less and less content is maintained by hand, more and more comes from a source that exists anyway. A baker shows croissants and coffee until ten o'clock, then the lunch offer. A sports shop brings up umbrellas when it rains. A furniture store takes a model out of the loop as soon as the till reports zero stock. Above all, this lowers the error rate, because a piece of information is only maintained in one place.

Every one of these sources needs the same protection: a fallback page for when it falls silent.

On the hardware side, less moves than the trade fair stands suggest, but three developments have arrived in practice.

LED walls are getting finer. Pixel pitches below a millimetre exist for indoor use, which brings the wall closer to the viewer without the dots becoming visible. Transparent versions behind shop-window glass keep the view into the shop clear, and curved ones follow a column.

Displays are getting thinner and lose their frames, which mainly helps installation. And then there is e-paper, the quiet alternative: price labels, direction signs, room signs, timetables. Such surfaces only draw power when they change, are excellently legible in sunlight and sometimes run for years on one battery. Colour is possible, the refresh stays slow, and there is no moving image. Where attention has to be won in two seconds, there is no way past a bright, moving surface. Where information merely has to be current, e-paper is often the wiser choice.

One topic is growing noticeably, from two directions: from customers and from the legislator. In Switzerland the Disability Equality Act obliges public bodies above all; in Europe the European Accessibility Act has applied since 2025 and also covers self-service devices. Anyone buying a kiosk or a totem today should expect stricter requirements. The good news: what works for a person with impaired sight also works for the passer-by walking past in the rain.

For all that is moving: the core of this book is untouched by it. A passer-by gives your screen two to three seconds, and in that time a thought forms or none does. It still comes down to the three things from the beginning: a goal you can state in one sentence, content looked after by someone with a name and a date in the calendar, and technology that suits the place rather than the other way round.

A personal word to close. Much of this book I did not learn at a desk, but on ladders, in shop windows in high summer and in conversations where a customer asked a question to which I had no good answer. I am grateful for both: to my team in Solothurn, who have made sure for years that an idea becomes an installation still running in its third winter. And to everyone who has entrusted us with their façade, their reception and their waiting room.

If while reading you thought of your own wall and are unsure whether your reasoning holds: ask somebody who installs such devices themselves, and ask early. And if you close the book and take away a single sentence, let it be this one: two seconds, one thought. Everything else is craft.