In this project, the PIR sensor connected to the NodeMCU board, detects any motion of a person and turns LED ON and turns OFF the LED when no motion is detected by it.

In this project, the PIR sensor connected to the NodeMCU board, detects any motion of a person and turns LED ON and turns OFF the LED when no motion is detected by it.


PIR sensor

PIR stands for Passive Infra-Red sensor. As the name says, it is a passive sensor which means it does not emit any infra-red rays but it senses the infra-red rays around the sensor range. The IR sensor is covered with a passive cube that has many layers of lenses to collect different wave patterns. Every living being generates heatwaves and these are detected by the PIR sensor and senses the motion. When the thermal signal is detected this sensor produces high analog signal and when nothing is detected it produces low analog signals.


A NodeMCU is a development board with an inbuilt Wi-Fi module in it. It is a basic and cost-efficient board to carry out projects using internet of things. The NodeMCU has ESP8266 microcontroller unit in it. The operation of this microcontroller is controlled with the programs used in Arduino thus making it very easier to use and also to learn basic IoT projects. This board has an inbuilt 2.4GHz antenna to receive Wi-Fi functions. This board has a memory of 4mb to store the data acting as ROM and 64Kb of RAM. This board operates at 3.3 volts and it is mandatory to operate the board at this voltage and not more than that as increasing the input voltage in this board may damage few GPIO pins (general input-output pins).

Pin Configuration

1. Vin: 3.3V can be provided at this pin as the supply to power on the board. This pin is used to power on the entire microcontroller.

2. GND: This pin is connected to the negative terminal of the battery.

3. RST: This pin resets the microcontroller and clears the memory.

4. EN: This pin is used to enable the operation of microcontroller.

5. 3V3: This pin provides 3V output and this can be used to power up some sensor units connected to the microcontroller.

6. SD1, CMD, SD0, CLK: These pins are used in SPI communication, that is it is used to transfer the signals between two microcontrollers, Rx and Tx modules with asynchronous transmission.

7. SD3, SD2: These pins can also function as asynchronous transmission or as GPIO pins.

8. RSV: These are two reserved pins used by the microcontroller and cannot be used in connecting any external circuits to it.

9. A0: This microcontroller only has one analog pin for Analog communication. This A0 pin is used in analog signal communication.

10. GPIO 1 – 16: This controller board has 16 input-output pins which be used as input or output pin based on the programming.

11. GP10 1, 3, 13, 15: This microcontroller has 2 UART communication pins, RX0, TX0 (GPIO 1 & GPIO 3) and RX1, TX1 (GPIO 13, GPIO15).



int PIR = D1;
void setup() {
 Serial.begin(9600);       // 9600 BITS TRANFERING TO PC PER SECOND

void loop() {
  if(digitalRead(PIR) == HIGH){
     Serial.println("Motion Detected");
       Serial.println("Motion Not Detected");
       delay(150);         // Delay to Avoid the fast print 

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