35.Home Automation - 09



In this post I'll show you how to make the sensor unit of the home automation system.


This unit is use to switch on/off the lights of the selected places(rooms). What this unit does is , it senses the movements by the attached PIR sensors.According to those movements , it sends signals to the main control unit for the switch on/off the lights.We can attach 7 sensors to this unit.

To make this unit we will need below parts list.

  • Arduino Nano module - 1
  • NRF24L01 RF module - 1
  • PIR sensors - 7
  • Prototyping board - 1
  • Led
  • Wires
  • Soldering Iron 

I have describe about the Arduino & RF module in previous posts.Now I'll describe about the PIR sensors.

PIR Sensor (passive infrared sensor)

A PIR-based motion detector is used to sense movement of people, animals, or other objects.As per the detection it sends signals as an output.This module works with 5v power connection. 

Now I'll show you how to assemble the sensor unit.As above image we need to connect the modules.The connections should be as below.

  • Arduino Nano VIN pin to +5V power connection
  • Arduino Nano GND pin to -5V power connection
  • NRF24L01 MISO pin with Arduino Nano D12 pin
  • NRF24L01 SCK pin with Arduino Nano D13 pin
  • NRF24L01 CE pin with Arduino Nano D9 pin
  • NRF24L01 MOSI pin with  Arduino Nano D11 pin
  • NRF24L01 CSN pin with Arduino Nano D10 pin 
Then PIR sensor connections should be like , 

  • All the PIR sensor DATA pins with Arduino Nano D2 up to D8 
  • All the PIR sensor VCC pins with Arduino Nano VCC pin
  • All the PIR sensor GND pins with Arduino Nano GND pin

After we made all the connection correctly , we have to upload the Sensor_Unit.ino file to the Arduino Nano using Arduino IDE. 

In next post I'll update you about next new function which I added to the system.

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