Arduino Multi-Sensor Simulator

LAB08: Hands-on Sensor Programming Without Hardware

Overview

This interactive Wokwi simulation lets you experiment with multiple sensors connected to an Arduino, exactly as covered in LAB08. No hardware required!

How to Use

1. Click “Play” to start the simulation
2. Interact with sensors (click potentiometer, adjust temperature slider)
3. View sensor readings in the Serial Monitor
4. Modify the code to experiment with different configurations

Multi-Sensor Data Logger

This simulation includes:

• Potentiometer (analog input) - simulates light/soil moisture sensors
• DHT22 - temperature and humidity sensor
• PIR Motion Sensor - digital motion detection
• LED indicators - visual feedback for thresholds

Custom Project

The embedded simulator opens a blank Arduino Uno project. Copy the code below to create the multi-sensor setup.

Starter Code

Copy this code into the Wokwi editor above:

// LAB08: Multi-Sensor Data Logger
// Edge Analytics Lab Book

// Pin definitions
const int POT_PIN = A0;      // Potentiometer (analog)
const int PIR_PIN = 2;       // PIR motion sensor (digital)
const int LED_GREEN = 8;     // Status LED
const int LED_RED = 9;       // Alert LED

// DHT22 would need library - using simulated values here
float temperature = 22.5;
float humidity = 45.0;

// Thresholds
const int LIGHT_THRESHOLD = 512;
const float TEMP_HIGH = 30.0;

void setup() {
  Serial.begin(115200);

  pinMode(POT_PIN, INPUT);
  pinMode(PIR_PIN, INPUT);
  pinMode(LED_GREEN, OUTPUT);
  pinMode(LED_RED, OUTPUT);

  Serial.println("=== Multi-Sensor Data Logger ===");
  Serial.println("Timestamp,Light,Temperature,Humidity,Motion");
}

void loop() {
  // Read sensors
  int lightValue = analogRead(POT_PIN);
  int motionDetected = digitalRead(PIR_PIN);

  // Simulate temperature drift
  temperature += random(-10, 11) / 100.0;
  humidity += random(-5, 6) / 10.0;
  humidity = constrain(humidity, 20, 80);

  // Print CSV format for data analysis
  unsigned long timestamp = millis();
  Serial.print(timestamp);
  Serial.print(",");
  Serial.print(lightValue);
  Serial.print(",");
  Serial.print(temperature, 1);
  Serial.print(",");
  Serial.print(humidity, 1);
  Serial.print(",");
  Serial.println(motionDetected);

  // LED indicators
  if (lightValue > LIGHT_THRESHOLD) {
    digitalWrite(LED_GREEN, HIGH);
  } else {
    digitalWrite(LED_GREEN, LOW);
  }

  if (temperature > TEMP_HIGH || motionDetected) {
    digitalWrite(LED_RED, HIGH);
  } else {
    digitalWrite(LED_RED, LOW);
  }

  delay(1000);  // Sample every second
}

Wiring Diagram

Add these components in Wokwi:

Component	Arduino Pin	Notes
Potentiometer	A0	Simulates analog sensor
PIR Sensor	D2	Motion detection
Green LED	D8	With 220Ω resistor
Red LED	D9	With 220Ω resistor

Exercises

Exercise 1: Sensor Calibration

Modify the LIGHT_THRESHOLD value and observe when the green LED turns on/off. What range of potentiometer values correspond to “low light” vs “bright”?

Exercise 2: Sampling Rate

Change delay(1000) to delay(100). What happens to:

• Serial Monitor output rate?
• Data file size (if you were logging)?
• Power consumption (in a real device)?

Exercise 3: Data Windowing

Add rolling average calculation:

// Add at top of file
const int WINDOW_SIZE = 5;
int lightBuffer[WINDOW_SIZE];
int bufferIndex = 0;

// In loop(), before printing
lightBuffer[bufferIndex] = lightValue;
bufferIndex = (bufferIndex + 1) % WINDOW_SIZE;

int smoothedLight = 0;
for (int i = 0; i < WINDOW_SIZE; i++) {
  smoothedLight += lightBuffer[i];
}
smoothedLight /= WINDOW_SIZE;

How does windowing affect noise in the readings?

Next Steps

After completing this simulation:

1. Level 3: Build the physical circuit with real sensors
2. LAB12: Stream this data to a Raspberry Pi for processing
3. LAB13: Store readings in a database

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About Wokwi

Wokwi is a free online simulator for Arduino, ESP32, and other embedded platforms. It runs entirely in your browser with no installation required.