How to Build a Simple Arduino-Based Humidity Sensor to Solve Your Dry Air Problems

Living with dry air can be uncomfortable and even unhealthy. Low humidity can cause issues like dry skin, nosebleeds, cracked lips, and respiratory irritation. Thankfully, building a simple Arduino-based humidity sensor can help you monitor and solve indoor dry air problems.

What You'll Need

To build a basic Arduino humidity sensor, you'll need the following components:

Circuit Design

Building the circuit is straightforward:

Arduino Humidity Sensor Code

The DHT sensor libraries include example sketches for reading humidity and temperature data. This code can be used as a basis:


include "DHT.h"

define DHTPIN 2 // Digital pin for sensor

define DHTTYPE DHT11 // Sensor type (DHT11/DHT22)


void setup() {

void loop() {
delay(2000); // Delay 2 sec between reads

float h = dht.readHumidity();
float t = dht.readTemperature();

if (isnan(h) || isnan(t)) {
Serial.println("Failed to read from DHT sensor!");

Serial.print("Humidity: ");
Serial.print(" %\t");
Serial.print("Temperature: ");
Serial.println(" *C ");

This prints the humidity and temperature readings to the Serial monitor every 2 seconds. Modify as needed for LCD display output.

Calibrating the Sensor

While DHT sensors are quite accurate out of the box, for best results it's recommended to calibrate against a known accurate device.

To calibrate:

Proper calibration ensures your humidity data is as precise as possible.

Enclosure and Placement

For long term use, it's best to add the sensor board to a protective enclosure. A small plastic project box works well.

Drill holes to expose the DHT sensor and display, and to run power and signal cables.

Place the enclosed sensor in a central area of the home at human level to monitor indoor humidity accurately. Keep away from drafts, vents, windows and doors.

Solving Low Humidity Issues

Once your Arduino humidity monitor is setup, here are some tips to raise humidity if it drops too low indoors:

With the help of your Arduino-based sensor, you can take the guesswork out of diagnosing and relieving dry indoor air. Spend less time worrying and more time breathing easy.