Automatic Smart Lights and Door Without Microcontroller

This automated smart lighting and door system operates entirely through hardwired analog and discrete logic, completely eliminating the need for a programmable microcontroller or complex software. At the heart of the detection stage is a Passive Infrared (PIR) sensor, which continuously monitors its field of view for changes in ambient infrared radiation emitted by human bodies. When a person approaches or enters the detection zone, the PIR sensor generates a positive voltage output signal. This output signal is directly routed to the control inputs of a 2-channel relay module. When energized by the sensor's signal, the electromagnetic coils inside the relay switch internal mechanical contacts, closing the circuits connected to the AC power source. One channel of the relay controls the room light, allowing household alternating current to flow directly to the lighting fixture. Simultaneously, the second relay channel triggers the door actuator, which provides the necessary electrical or mechanical stimulus to unlock or open the entryway. Once the occupant leaves the area and motion is no longer detected, the PIR sensor output drops back to its baseline state, de-energizing the relay coils, cutting power to the room light, and returning the door actuator to its default locked position.