This page treats a scrolling text display as a problem in viewing geometry, which is what it is on a hillside town. It covers the angles you will really be read from, how a sloping street changes the mounting height, why a few degrees of rake matters more than an extra hundred nits, how to derive the character height when the reader is above you, why dusk arrives here before the clock says so, and what a local electrician can put right without anybody driving 371 kilometres.
LED scrolling sign in Trbovlje — manufacturing, installation, quote
Slovenia · 371 km from our plant in Győr
Nearly every guide to scrolling text boards assumes a flat street and a reader standing straight in front. Trbovlje offers neither. The town is terraced up two valley sides, its streets climb, and a board mounted at a normal height above a shop door will be read from below by people coming up from the valley floor and from above by people coming down from the housing on the slope. Panels have a finite viewing cone, and a text strip is far less forgiving about it than a video wall, because a line of letters that loses contrast simply stops being a line of letters. The geometry, not the wording, is what decides whether a board works here.
The angle you will actually be read from
Above, below, and rarely straight on
Stand at the position you have in mind and look back at the wall from every place a reader will realistically be. On most Trbovlje frontages you will find you are looking up at it from one side and down at it from the other, with a genuine spread of perhaps fifty degrees between the extremes. That spread is the specification. Panels hold their contrast well within a cone around the perpendicular and fall off outside it, and outside that cone a scrolling line goes grey long before it goes dark. Write the two extreme angles down; they will decide the mounting height, the rake and, more often than people expect, the position itself.
Mounting height on a street that climbs
Two metres of fall along one shop front
A gradient that is barely noticeable when you walk it is substantial across the width of a building. A shop front eight metres wide on a one-in-four street drops two metres from one end to the other, which means that a board hung level with the door at the upper end is at head height at the lower end and well above it at the upper. The usual mistake is to set the height from the doorway. Set it instead from the middle of the frontage and check both ends, and be prepared to mount lower than instinct suggests, because a text strip read from underneath at a steep angle is the single most common complaint we are called out to.
Rake, and what a few degrees buys
Cheaper than brightness, and it works
Where the readers are mostly below, tilting the board down by a few degrees brings the perpendicular into the middle of the audience rather than into the sky. It costs a bracket. The alternative that people reach for first, more output, does not solve an angle problem at all: a washed-out line seen from outside the cone stays washed out when you brighten it, and now it also annoys the neighbours. We decide the rake on the survey with an inclinometer and fix it in the bracket, because an adjustable mounting will eventually be knocked out of position and nobody will notice.
Character height when the reader is twenty metres above
Distance along the line of sight, not along the pavement
The old rule of thumb, roughly a centimetre of letter height for every four to five metres of reading distance, is sound, but the distance that counts is the slant distance from eye to board. Somebody on the terrace above is thirty metres away along the sightline even though they are only fifteen metres away on the map, and they are also seeing the letters foreshortened. Both effects push the character height up. On a strip, the character height is set by the number of tile rows, in 16 centimetre steps, so this arithmetic is what decides whether you buy a board one row tall or two, and that is a decision you cannot revisit later.
Dusk in a deep valley, and the dimming schedule
The ridge takes the light before the clock does
In a valley this narrow the sun leaves the frontages a good while before sunset, and there is a long period during which the sky is still bright but the street is in shadow. A board running at daytime output through that window is glaring; a board running at night output is washed out at midday. Two levels are not enough here. We set a short third step for the shoulder period and drive all of it from the controller's schedule rather than from a photocell, because a photocell mounted on a shaded wall will switch at the wrong moment every day of the year and nobody will work out why.
What a local electrician can put right
Modules, a controller and the parts shipped with the board
A text board has few parts: tiles, a power supply, a controller and a cable. We ship spares of the first two with the board and we label everything, so that a competent local electrician can swap a dead module or a failed supply without specialist knowledge. Faults are diagnosed remotely first, over the same network or Wi-Fi connection used to load the message list. Warranty runs to one or two years depending on the configuration. The whole arrangement exists so that the 371 kilometres between here and the workshop is an accounting fact rather than an operational one.
