Lab set Program-9

Weather Station Readings Using Arduino (Tinkercad)

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Objective

To develop a simple weather-station prototype using Arduino that measures temperature, humidity, and light intensity using simulated sensors in Tinkercad.
(DHT sensor is not available in Tinkercad, so we will use two potentiometers to simulate Temperature & Humidity and a photoresistor to simulate Light level.)

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Learning Outcomes

By the end of this experiment, students will be able to:

1. Understand the concept of a basic weather-monitoring system.

2. Simulate unavailable sensors in Tinkercad using analog components.

3. Read multiple sensor inputs and process them in Arduino.

4. Display combined weather readings using the Serial Monitor.

5. Implement simple decision logic for weather classification.

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Components (from Tinkercad Palette)

• Arduino Uno

• Potentiometer – 2 Nos. (as Temperature & Humidity sensors)

• Photoresistor (LDR) (as Light sensor)

• 10kΩ resistor (for LDR voltage divider)

• Breadboard

• Jumper wires

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Circuit Wiring (Exact)

1. Temperature Sensor (Potentiometer-1)

• Outer pin → 5V

• Other outer pin → GND

• Middle pin → A0

2. Humidity Sensor (Potentiometer-2)

• Outer pin → 5V

• Other outer pin → GND

• Middle pin → A1

3. Light Sensor (Photoresistor / LDR)

• One leg → 5V

• Other leg → A2 AND also to GND through 10kΩ resistor

(LDR + 10kΩ forms a voltage divider.)

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Arduino Sketch

int tempPin = A0;       // Temperature sensor (Potentiometer)
int humidPin = A1;      // Humidity sensor (Potentiometer)
int lightPin = A2;      // LDR sensor
float temperature = 0.0;
float humidity = 0.0;
int lightValue = 0;

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

void loop() {
  // Read sensor values
  int tempRaw = analogRead(tempPin);
  int humidRaw = analogRead(humidPin);
  lightValue = analogRead(lightPin);

  // Map values to realistic ranges
  temperature = map(tempRaw, 0, 1023, 10, 45);     // Simulated °C
  humidity = map(humidRaw, 0, 1023, 20, 90);       // Simulated %
  int lightPercent = map(lightValue, 0, 1023, 0, 100);

  // Print weather information
  Serial.print("Temperature: ");
  Serial.print(temperature);
  Serial.print(" C | Humidity: ");
  Serial.print(humidity);
  Serial.print(" % | Light: ");
  Serial.print(lightPercent);
  Serial.println(" %");

  delay(700);
}

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How It Works 

• Potentiometer-1 simulates temperature. Turning it left/right changes the analog reading representing cool or hot conditions.

• Potentiometer-2 simulates humidity.

• LDR gives light levels—covering it reduces the reading, shining light increases it.

• Arduino reads all three sensor values through A0, A1, A2.

• Values are scaled to human-readable units:

  • Temperature (10–45°C)

  • Humidity (20–90%)

  • Light (0–100%)

• The Serial Monitor displays live weather readings like a small weather station.

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Common Mistakes & Quick Fixes

Problem	Cause	Fix
Temperature or humidity always 0	Middle pin of pot not on A0/A1	Reconnect jumper properly
Light values not changing	Wrong LDR wiring	Ensure 10k resistor goes from A2 to GND
Readings jump too fast	Pot is loose	Turn slowly or adjust delay
No Serial Monitor output	Serial.begin missing	Confirm Serial.begin(9600) is in setup

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Viva / Check-Your-Understanding

1. Why did we use potentiometers instead of real sensors?

2. How does a voltage divider work for LDR?

3. What environmental factors can be measured in a weather station?

4. Give examples of real sensors used for temperature and humidity.

5. What is the purpose of converting analog readings into meaningful units?

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Extensions (Mini-Tasks)

• Display the readings on an LCD (16×2).

• Add a buzzer to alert when temperature crosses 40°C.

• Log weather data using Serial Plotter.

• Publish readings to an IoT dashboard (Thingspeak or Blynk).

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Lab Record (Suggested Headings)

1. Title

2. Objective

3. Components Used

4. Circuit Diagram (Tinkercad Screenshot)

5. Arduino Code

6. Output (Serial Monitor readings)

7. Explanation

8. Learning Outcomes

9. Viva Questions

10. Extensions

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