Logi Escalier -

Mrs. Dupont goes down to get her mail. She presses the button on the 2nd floor, the light turns on for 60 seconds. She retrieves her mail and returns to the 2nd floor in 45 seconds. The light is still on. She enters her apartment. Fifteen seconds later, the timer ends, and the light turns off.

Imagine an apartment building in the 1920s. A resident finishes their shift at the factory and climbs the dark stairs to the fourth floor. At the top, there is a switch. But the entrance? That switch is at the bottom. To turn on the light before ascending, they had to walk into the pitch-black stairwell, feel for the switch, turn it on, run up the stairs, and then… the light stayed on. All night. All morning. Wasting electricity and burning out bulbs. logi escalier

In the early days of electricity, controlling a light was a simple, private affair. You flipped a switch on the wall, the filament glowed, and the room filled with light. But as buildings grew taller and hallways stretched longer, a problem emerged: the staircase . She retrieves her mail and returns to the

What was needed was a logic —a set of rules for the electricity to follow. This was the birth of the . The Core Principle: Temporary Presence The logic is simple, elegant, and almost human: When a person requests light, provide it, but do not waste it. Assume they only need enough time to climb one flight of stairs. Fifteen seconds later, the timer ends, and the

The solution was a more advanced : the impulse relay with a "staircase" function .

The light does not know your name. It does not know your floor. But thanks to the logi escalier , it knows exactly when you need it—and, more importantly, when to say goodnight.