Arduino Weather Station using DHT11 and LCD Display

Temperature and humidity are the two quantities behind almost every local weather report, greenhouse controller and room-comfort system, yet students usually meet them only as numbers on a phone screen. This project makes both quantities visible on a bench: an Arduino Nano reads a DHT11 sensor and shows live temperature and humidity on a 16 by 2 character LCD, so the effect of a heat source or a spray of water can be watched as it happens. The build is deliberately small and local: no wireless link, no cloud account, no phone app, just a sensor, a controller and a display that update together.

The end-to-end mechanism runs from the air in the room to two numbers on a screen. The DHT11 sensor measures the temperature and humidity of the air immediately around it and reports both as digital values. The Arduino Nano polls the sensor at regular intervals, formats the two readings, and writes temperature to the first LCD line and humidity to the second. Because the polling loop never stops, the display follows the room: when a heat source warms the air near the sensor the temperature line climbs, and when a water spray moistens the air near the sensor the humidity line climbs, with both changes visible within seconds and settling back as the air returns to normal.

1. The builder assembles the station: the Arduino Nano, DHT11 sensor module and 16x2 LCD are mounted on a single prototyping board and wired with jumper wires, powered from a 5 V USB supply.
2. The builder checks the sensor alone: the DHT11 readings are compared with a room thermometer and a general sense of the room's dampness, so a faulty sensor is caught before the display is trusted.
3. The builder checks the display alone: the two-line layout is confirmed, so temperature and humidity are never confused on screen.
4. For the room-reading demonstration, the builder powers the station and shows the display tracking ordinary room temperature and humidity over several minutes.
5. For the heat response demonstration, the builder aims a heat source near the sensor and watches the temperature reading climb toward the high thirties on the display.
6. For the water-spray response demonstration, the builder sprays water near the sensor and watches the humidity reading climb past eighty percent on the display, then settle back as the air dries.
7. The builder writes up the results honestly, including the sensor's accuracy limits and every condition under which the readings should not be trusted.

Tech stack:

• Arduino Nano · ATmega328P controller board
• DHT11 sensor · temperature and humidity sensing
• 16x2 LCD display · live readings display
• Jumper wires and prototyping board · sensor and display wiring
• 5 V USB supply · bench power for the station
• Heat response test · temperature channel verification
• Water-spray response test · humidity channel verification

This station combines a small set of parts into a complete sensing demonstration rather than a display that shows fixed numbers. First, the sensor is read live and continuously, so the display tracks the room instead of showing a single measurement. Second, the two response tests turn the station into something an examiner can challenge: warm the sensor and the temperature must rise, spray water near it and the humidity must rise, with both changes visible within seconds. Third, the two-line display keeps the quantities separate and readable at a glance, so a visitor can read temperature and humidity without a manual. Fourth, the whole station runs from a single 5 V USB supply on one prototyping board, so it can sit on any table and run for a whole demonstration.

• [Live temperature and humidity readings] The DHT11 sensor is polled continuously by the Arduino Nano, and the 16x2 LCD updates both readings as the room changes, so the display tracks the air instead of showing a fixed value — implemented in the base build.
• [Heat response test] A heat source aimed near the sensor raises the temperature reading toward the high thirties, which the display shows within seconds, proving the temperature channel is genuinely sensing — implemented in the base build.
• [Water-spray response test] A spray of water near the sensor raises the humidity reading past eighty percent, which the display shows within seconds, proving the humidity channel is genuinely sensing — implemented in the base build.
• [Two-line LCD layout] Temperature on the first line and humidity on the second, so both quantities stay separate and readable at a glance without a manual — implemented in the base build.
• [Single-board tabletop station] Arduino Nano, DHT11 sensor and LCD on one prototyping board running from a 5 V USB supply, so the station sits on any table and runs continuously — implemented in the base build.
• [Wireless logging and forecasting] Future scope only, not implemented: adding a Wi-Fi module with cloud logging, graphs and forecasts, listed as an extension rather than a claimed feature, since the base build is a local display-only station.

• Complete fabricated tabletop weather station (Arduino Nano, DHT11 sensor module, 16x2 LCD, prototyping board, jumper wires, 5 V USB power lead)
• Sensor-reading firmware (DHT11 polling loop, two-line LCD formatting, continuous display update)
• Setup and testing guide (sensor check procedure, display check procedure, heat response test, water-spray response test, accuracy-limits worksheet)
• Project report PDF (sensor interfacing background, polling-loop design, response-test demonstration results, honest accuracy observations)
• PPT presentation for final review
• Viva Q&A preparation document (DHT11 working principle, polling versus interrupts, LCD interfacing, accuracy limits, local versus wireless stations)