CIPAD 32: Comment facilement contrôler la luminosité du rétroéclairage d'un afficheur lcd standard

Introduction

In this tutorial, we will learn how to control the brightness of the backlight on a standard LCD display using PWM (Pulse Width Modulation) with Arduino. This technique is useful for adjusting display visibility in various lighting conditions, enhancing user experience in your electronic projects.

Step 1: Gather Required Components

To get started, ensure you have the following components ready:

• Arduino board (e.g., Arduino Uno)
• Standard LCD display (16x2 or similar)
• 10k Ohm potentiometer
• Breadboard and jumper wires
• Resistor (optional, based on your setup)

Practical Advice

• Make sure your Arduino IDE is installed and updated.
• Familiarize yourself with basic wiring if you're new to electronics.

Step 2: Wiring the Components

Follow these steps to connect the components properly:

1. Connect the LCD:

   • Connect the VSS pin to GND.
   • Connect the VDD pin to +5V.
   • Connect the VO pin to the middle pin of the potentiometer.
   • Connect one outer pin of the potentiometer to GND and the other to +5V.
   • Connect RS pin to a digital pin (e.g., pin 12).
   • Connect RW pin to GND.
   • Connect E pin to another digital pin (e.g., pin 11).
   • Connect D0 to D7 pins to digital pins (e.g., pins 5 to 10).

2. Connect the PWM Output:

   • Choose a PWM-capable pin on the Arduino (e.g., pin 9).
   • Connect this pin to the anode (+) of the LCD backlight.
   • Connect the cathode (-) of the backlight to GND.

Practical Advice

• Double-check all connections to avoid short circuits.
• Use a breadboard to keep your setup organized.

Step 3: Writing the Arduino Code

Now, let's write the code to control the LCD backlight brightness using PWM. Here’s a simple example:

#include <LiquidCrystal.h>

// Initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 5, 6, 7, 8);

void setup() {
  lcd.begin(16, 2);
  lcd.print("Hello, World!");
}

void loop() {
  for (int brightness = 0; brightness <= 255; brightness++) {
    analogWrite(9, brightness); // Control the brightness
    delay(10); // Wait for 10 milliseconds
  }
  for (int brightness = 255; brightness >= 0; brightness--) {
    analogWrite(9, brightness);
    delay(10);
  }
}

Practical Advice

• Adjust the delay in the loop to change the speed of brightness transition.
• Test and tweak the brightness levels based on your specific display requirements.

Step 4: Uploading and Testing the Code

1. Connect your Arduino to your computer via USB.
2. Open the Arduino IDE and paste the code into a new sketch.
3. Select the correct board and port from the Tools menu.
4. Upload the code to your Arduino.

Practical Advice

• Monitor the Serial Monitor for any error messages during upload.
• Ensure your LCD is functioning correctly by checking for displayed text.

Conclusion

You have now successfully controlled the brightness of an LCD backlight using PWM with Arduino. This skill can be applied to various projects where display visibility is crucial. Consider experimenting with varying brightness levels and implementing additional features, such as automatic brightness adjustment based on ambient light. For further exploration, check out the project link provided in the video description. Happy tinkering!