Saturday, September 30, 2023

Automatic Lights and Door Without Microcontroller

Ashwini Kumar Sinha

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There are various IoT devices available in the market that perform tasks based on voice commands such as opening a door or switching on/off the lights and many others. Constructing them is a complex task and costly as well for which a microcontroller is required along with few sensors. And programming them consumes a lot of resources.  So let’s make a smart door and a smart lights that senses human motion, and which automatically operates without needing a microcontroller.

Bill Of Materials

Here we use the PIR sensor to sense human motion. This helps us in detecting whether a person is coming through the door of a room or the garage door. Next, connect the output signal of the motion sensor to the input of the relay module. In the relay module, connect the live wire carrying current from the AC power source to the common (COM) pins (COM) of the 2-channel relay. Next, connect the live wire of both the light and the door actuator (that opens the door) to the normally open (NO) relay pins.  

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The neutral and earth wire of both the light and door actuator is connected to neutral and actuator pins.


Connect the components as shown in the circuit diagram.

Circuit diagrm for Automatic Lights and Door Without Microcontroller
Circuit diagrm for Automatic smart Lights and Door Without Microcontroller


Now place the PIR sensor above the door and power it. While walking towards the door, the sensor detects the human motion and transmits a signal to the relay module, which activates a relay plunger to move and switch on the room light. The door actuator also gets triggered, which unlocks the door.




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