I was looking for a room in Baraha to get some work done. However, to check some of the rooms there, I had to manually open the doors to see if they were occupied or not. I found the whole process inefficient, since I had to apologize if the room was occupied. The experience was embarrassing, and I was sure there were better ways to avoid it from happening.
So I decided to build my final project based on this idea: a detection machine that lets people know if the room is occupied or not. I found further inspiration from the parking lights installed in some of the malls in Abu Dhabi. There are lights on top of a parking space, and those lights display colors depending on the availability of the space.
At first, I thought using ultrasonic sensors would work. The idea was to have a sensor installed on the door to check if someone walks across the doorway: if they do, activate the light. However, ultrasonic sensors spread in an arc, so they may cause more errors than I expect. Next, I considered using PIR sensors that detect motion and heat. This is a good approach, but since PIR detects only movement, there are issues when people inside do not move: if they sit still and work on their projects, the sensor would assume the room is empty. This defeats the whole purpose of the project.
So for my sensors, I decided to use IR beam-break sensors. It is a single-line sensor that triggers when something gets in the way, so I thought it would be perfect for this project. If I have two of those sensors, I would also be able to determine whether a person enters or exits the room, allowing me to turn the LED on or off. It would be better to have the IR beam sensor installed at the door and a PIR motion sensor installed inside the room for a two-way detection system to ensure fewer errors, but cost-wise, I found that it was not worth having two sensors. I want to buy the sensors so that I can keep the project for my own use without having to return it later.
For the display, I will either order an LED panel or just use a circular LED display to show the status. Universal language such as red light means it is occupied, and green light means that the room is available. I can get more creative and use LED panels to show art installations, which would make it look more like an interactive media project.