Update README.md

README.md

@@ -1 +1,8 @@
-# ElevatorController
+# ElevatorController
+
+an elevator, moving people up and down between three floors. A picture of the situation is shown on the right.
+In the elevator car, there are four buttons: buttons 1, 2, 3 to go to the respective floor, and a stop button to stop the elevator. On each floor, there is a button to call the elevator. Furthermore, the elevator has two sensors, the first indicating if the elevator is on a floor or in between two floors, the second one indicating if the elevator's door is closed or not. There is also a linear position sensor for measuring the position of the elevator in the elevator shaft.
+
+The elevator is moved up and down by a motor that is on the roof of the building, at a maximum speed of 50cm/s. The motor is controlled by two signals, one for moving the elevator up and one for moving it down; both signals are driven using pulse-width modulation (PWM) to enable smooth acceleration and deceleration of the elevator car. The distance between two floors is 400cm.
+
+The goal of this project is to implement and test the software controlling the elevator.