Build a Wireless Weather Station with NRF24L01 & Arduino

Build a Wireless Weather Station with NRF24L01 & Arduino

Building a wireless weather station NRF24L01 Arduino project is one of the most satisfying weekend maker builds — it combines environmental sensing, wireless communication, and real-time data display into a practical device you can actually use. In this complete guide, you will build a two-node weather monitoring system: one outdoor sensor node that reads temperature, humidity, and atmospheric pressure, and one indoor display station that receives the data wirelessly over NRF24L01 and shows it on an OLED screen. Let us get started!

Project Overview and Features

This wireless weather station consists of two Arduino-based nodes:

Outdoor Sensor Node:

• DHT22 sensor for temperature and humidity
• BMP280 sensor for barometric pressure and altitude
• NRF24L01 module for wireless data transmission
• Arduino Nano (small form factor, 3.3V/5V compatible)
• Battery-powered with sleep mode for energy efficiency

Indoor Display Station:

• NRF24L01 module to receive data
• 0.96″ OLED display showing all sensor readings
• Arduino Uno or Nano as the hub
• USB powered from any phone charger

The system transmits sensor data every 30 seconds. The outdoor node enters low-power sleep between transmissions, extending battery life significantly. All readings are displayed in real time on the OLED with automatic screen updates.

Full Components List

0.96 Inch I2C OLED LCD Module (White SSD1306)

Perfect for the weather station display node. This white SSD1306 OLED shows crisp text and graphics with just 2 wires (SDA/SCL), leaving plenty of pins free for other functions.

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Outdoor Sensor Node: Wiring Guide

Connect the outdoor sensor node components to Arduino Nano as follows:

NRF24L01 to Arduino Nano:

• VCC → 3.3V (use external AMS1117 regulator, not Nano’s onboard 3.3V)
• GND → GND
• CE → D9, CSN → D10, SCK → D13, MOSI → D11, MISO → D12

DHT22 to Arduino Nano:

• VCC → 5V, GND → GND, DATA → D2
• Add 10 kΩ pull-up resistor between DATA and VCC

BMP280 to Arduino Nano (I2C):

• VCC → 3.3V, GND → GND, SDA → A4, SCL → A5

Power: Connect 18650 battery (3.7V nominal) through an AMS1117-5V regulator to Nano’s VIN pin. A separate AMS1117-3.3V powers the NRF24L01 and BMP280.

Indoor Display Station: Wiring Guide

NRF24L01 to Arduino (same SPI wiring as outdoor node)
OLED (SSD1306 I2C) to Arduino: SDA → A4, SCL → A5, VCC → 3.3V, GND → GND

Sensor Node Arduino Code

Install these libraries before compiling: RF24 (TMRh20), DHT sensor library (Adafruit), Adafruit BMP280.

#include <SPI.h>
#include <RF24.h>
#include <DHT.h>
#include <Adafruit_BMP280.h>
#include <avr/sleep.h>
#include <avr/wdt.h>

#define DHTPIN 2
#define DHTTYPE DHT22

RF24 radio(9, 10);
DHT dht(DHTPIN, DHTTYPE);
Adafruit_BMP280 bmp;

const uint64_t txPipe = 0xF0F0F0F0E1LL;

struct WeatherData {
  float temperature;   // from DHT22
  float humidity;      // from DHT22
  float pressure;      // from BMP280 (hPa)
  float altitude;      // from BMP280 (metres)
  float heatIndex;     // computed
  uint32_t readingID;
};

uint32_t readingCounter = 0;

void setup() {
  Serial.begin(9600);
  dht.begin();
  if (!bmp.begin(0x76)) {
    Serial.println("BMP280 not found! Check wiring.");
  }
  bmp.setSampling(Adafruit_BMP280::MODE_FORCED,
                  Adafruit_BMP280::SAMPLING_X2,
                  Adafruit_BMP280::SAMPLING_X16,
                  Adafruit_BMP280::FILTER_X16,
                  Adafruit_BMP280::STANDBY_MS_500);

  radio.begin();
  radio.setPALevel(RF24_PA_LOW);
  radio.setDataRate(RF24_250KBPS);
  radio.setChannel(108);
  radio.openWritingPipe(txPipe);
  radio.stopListening();
  Serial.println("Sensor node ready");
}

void loop() {
  delay(2000); // DHT22 needs 2s between readings

  WeatherData data;
  data.temperature = dht.readTemperature();
  data.humidity    = dht.readHumidity();
  data.pressure    = bmp.readPressure() / 100.0F; // convert Pa to hPa
  data.altitude    = bmp.readAltitude(1013.25);   // sea level pressure
  data.heatIndex   = dht.computeHeatIndex(data.temperature, data.humidity, false);
  data.readingID   = ++readingCounter;

  if (isnan(data.temperature) || isnan(data.humidity)) {
    Serial.println("DHT22 read failed!");
    return;
  }

  bool success = radio.write(&data, sizeof(data));
  Serial.print("Sent reading #");
  Serial.print(data.readingID);
  Serial.print(" Temp:");
  Serial.print(data.temperature);
  Serial.print(" Hum:");
  Serial.print(data.humidity);
  Serial.print(" Press:");
  Serial.print(data.pressure);
  Serial.println(success ? " [OK]" : " [FAIL]");

  // Sleep for ~28 seconds (8s WDT x 3 + 4s = ~28s + 2s DHT delay = 30s total)
  for (int i = 0; i < 3; i++) {
    set_sleep_mode(SLEEP_MODE_PWR_DOWN);
    sleep_enable();
    wdt_enable(WDTO_8S);
    sleep_mode();
    sleep_disable();
  }
  delay(4000);
}

Display Station Code

Install the Adafruit SSD1306 and Adafruit GFX libraries for the OLED display.

#include <SPI.h>
#include <RF24.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128
#define SCREEN_HEIGHT 64

RF24 radio(9, 10);
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, -1);

const uint64_t rxPipe = 0xF0F0F0F0E1LL;

struct WeatherData {
  float temperature;
  float humidity;
  float pressure;
  float altitude;
  float heatIndex;
  uint32_t readingID;
};

WeatherData lastReading;
bool hasData = false;

void setup() {
  Serial.begin(9600);

  if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
    Serial.println("OLED not found!");
  }
  display.clearDisplay();
  display.setTextColor(SSD1306_WHITE);
  display.setTextSize(1);
  display.setCursor(10, 20);
  display.println("Weather Station");
  display.setCursor(15, 35);
  display.println("Waiting for data...");
  display.display();

  radio.begin();
  radio.setPALevel(RF24_PA_LOW);
  radio.setDataRate(RF24_250KBPS);
  radio.setChannel(108);
  radio.openReadingPipe(1, rxPipe);
  radio.startListening();
  Serial.println("Display station ready");
}

void updateDisplay(WeatherData &d) {
  display.clearDisplay();
  display.setTextSize(1);

  // Title
  display.setCursor(20, 0);
  display.println("WEATHER STATION");
  display.drawLine(0, 9, 127, 9, SSD1306_WHITE);

  // Temperature
  display.setCursor(0, 13);
  display.print("Temp:  ");
  display.print(d.temperature, 1);
  display.println(" C");

  // Humidity
  display.setCursor(0, 25);
  display.print("Humidity: ");
  display.print(d.humidity, 1);
  display.println("%");

  // Pressure
  display.setCursor(0, 37);
  display.print("Press: ");
  display.print(d.pressure, 1);
  display.println(" hPa");

  // Heat Index
  display.setCursor(0, 49);
  display.print("HeatIdx: ");
  display.print(d.heatIndex, 1);
  display.println(" C");

  // Reading counter
  display.setCursor(90, 57);
  display.print("#");
  display.print(d.readingID);

  display.display();
}

void loop() {
  if (radio.available()) {
    WeatherData received;
    radio.read(&received, sizeof(received));
    lastReading = received;
    hasData = true;
    Serial.print("Received #"); Serial.println(received.readingID);
    updateDisplay(received);
  }
}

0.96 Inch SPI OLED LCD Module 7-pin (White SSD1306)

Faster refresh SPI OLED perfect for the weather station display station. White on black display ensures maximum readability even in low light conditions.

View on Zbotic

Weatherproofing and Enclosure Tips

For the outdoor sensor node, proper housing is essential. Here are proven strategies used by Indian makers:

Enclosure selection: Use a junction box rated IP65 or IP67 (widely available at electrical shops for ₹50–150). The DHT22 sensor should be mounted outside the box in a radiation shield (a stack of white plastic discs that prevents direct sunlight from heating the sensor while allowing airflow).

Cable glands: Seal all cable entry points with rubber cable glands to prevent water ingress. Apply silicone sealant around the sensor probe where it passes through the enclosure wall.

Conformal coating: Apply acrylic conformal coating (available in aerosol form) to all PCBs and solder joints. This prevents corrosion from humidity — critical in coastal areas and monsoon seasons.

Antenna orientation: Keep the NRF24L01 module’s antenna oriented vertically (pointing up or down) for best omnidirectional radiation pattern. For the PA+LNA version, route the coaxial cable through a cable gland and mount the antenna on the outside of the enclosure.

Battery housing: Use a sealed 18650 holder inside the IP65 box. In hot Indian summers, lithium cell performance degrades above 45°C — paint the enclosure white to reflect sunlight and reduce internal temperature. For permanent installations, add a small 1W solar panel with a TP4056 LiPo charger module.

Ai Thinker LoRa Ra-01H Module

Want to upgrade your weather station for farm-scale use? Replace NRF24L01 with LoRa for kilometre-range wireless data transmission — ideal when your outdoor node is far from the display station.

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0.96 Inch SPI OLED LCD Module (Blue SSD1306)

Elegant blue OLED display for your indoor weather station hub. The blue-on-black colour scheme gives a premium feel to your weather display unit.

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Frequently Asked Questions