Process

The PIR sensor was used to detect people entering the room. Initially, I thought the proxy sensor on the Arduino would be sufficient, but its detection range was too short, so I opted for a separate sensor. The PIR sensor can detect movement within approximately 10m of the sensor. However, I had difficulty understanding its sensitivity and feedback time because the knob on the sensor was not intuitive. The machine produced a puff of air with the help of a blower, which initially confused me because the blower had four wires. After researching, I learned that it was a PWM blower, which stands for "pulse width modulation." The PWM 4-pin configuration includes GND, Voltage, Fan Speed, and Fan Speed Controller. I used a relay to control the air movement because I wanted short bursts of air rather than continuous airflow. I also designed the machine to reveal the fan through a box, resembling a person peeking out. The small servo could function without any issues, but I required a standard-sized servo due to the large blower, which needed an additional power source. The four AA batteries (total 6V) functioned satisfactorily, but the battery life was too short. I attempted to switch to the 5V USB socket; however, it did not have sufficient power to activate the blower. To stop the airflow, I utilized a flax sensor to detect it.