Ambient Light Level Tracker

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To build an IoT project using Arduino to measure ambient light levels and display the result on an I2C LCD screen in percentage, you can follow these steps:

Components Required:

  1. Arduino Uno (or any other compatible board)
  2. LDR (Light Dependent Resistor) or Photoresistor
  3. 10k Ohm Resistor (for LDR voltage divider circuit)
  4. I2C LCD Display (1602 LCD or any other compatible I2C screen)
  5. Jumper wires
  6. Breadboard
  7. Optional: Wi-Fi module like ESP8266 or ESP32 (for IoT connectivity, if you want to send data to a cloud or web server)

Wiring:

  1. LDR and Voltage Divider:
    • Connect one leg of the LDR to 5V on the Arduino.
    • Connect the other leg of the LDR to the A0 pin (analog input) on the Arduino.
    • Connect a 10k ohm resistor between the LDR and GND (ground) to form a voltage divider. This allows the Arduino to measure the varying voltage based on light intensity.
  2. I2C LCD:
    • Connect VCC of the I2C LCD to 5V.
    • Connect GND to Ground.
    • Connect SDA (Data Line) to A4 pin on Arduino (for Arduino Uno).
    • Connect SCL (Clock Line) to A5 pin on Arduino (for Arduino Uno).

Arduino Code:

Here’s the step-by-step code to read the ambient light level, convert it to a percentage, and display it on the I2C LCD.

#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Create an LCD object with I2C address 0x27, and 16 columns and 2 rows
LiquidCrystal_I2C lcd(0x27, 16, 2); // Update this with your I2C address if necessary

// Pin connected to the LDR
const int ldrPin = A0;

void setup() {
  // Initialize serial communication for debugging
  Serial.begin(9600);

  // Initialize the LCD using the correct function
  lcd.init();       // Use 'init()' instead of 'begin()'
  lcd.backlight();  // Turn on the backlight

  // Display initial message
  lcd.setCursor(0, 0);
  lcd.print("Ambient Light:");

  delay(1000);
}

void loop() {
  // Read the value from the LDR
  int ldrValue = analogRead(ldrPin);

  // Map the LDR value (0 to 1023) to a percentage (0 to 100)
  int lightPercentage = map(ldrValue, 0, 1023, 0, 100);

  // Clear the LCD and display the percentage
  lcd.setCursor(0, 1);  // Move to the second row
  lcd.print("Light: ");
  lcd.print(lightPercentage);
  lcd.print("%");

  // Print the value for debugging
  Serial.print("LDR Value: ");
  Serial.print(ldrValue);
  Serial.print(" | Light Percentage: ");
  Serial.println(lightPercentage);

  delay(1000); // Update every 1 second
}

Explanation of the Code:

  1. Libraries: The Wire library is for I2C communication, and the LiquidCrystal_I2C library is used to control the I2C LCD.
  2. LCD Initialization: We create an LCD object with the I2C address 0x27 (this is a common address, but your module may use a different address). The LCD is initialized with 16 columns and 2 rows.
  3. Reading LDR: The LDR is connected to an analog pin (A0). We use the analogRead() function to get a value between 0 and 1023, where 0 represents darkness and 1023 represents full brightness.
  4. Mapping: We use the map() function to convert the analog value (from 0 to 1023) into a percentage (from 0 to 100). This value is then displayed on the LCD.
  5. Display Update: Every second (delay(1000)), the LCD screen is updated to show the current ambient light level in percentage.

Conclusion:

This simple project helps you measure ambient light levels and display them on an LCD.