CIPAD leçon 15: comment fabriquer un Ohmmètre Arduino À sélection automatique..

Introduction

This tutorial guides you through the process of creating an automatic selection ohmmeter using Arduino. This project is ideal for beginners looking to enhance their skills in Arduino programming and electronics. By following these steps, you'll understand how to measure resistance automatically, making it a practical tool for various electronic projects.

Step 1: Gather Your Materials

Before starting, ensure you have the following components:

• Arduino board (e.g., Arduino Uno)
• 16x2 LCD display
• Resistors (various values)
• Push buttons (for selection)
• Breadboard and jumper wires
• Multimeter (for calibration)

Practical Tip

Organize your components and tools to streamline the assembly process.

Step 2: Set Up the Circuit

Follow these steps to wire the components:

1. Connect the LCD Display:

   • Connect the LCD's pins to the Arduino as follows:
     • RS to digital pin 12
     • E to digital pin 11
     • D4 to digital pin 5
     • D5 to digital pin 4
     • D6 to digital pin 3
     • D7 to digital pin 2
   • Connect VSS to ground and VDD to 5V.

2. Connect the Resistors:

   • Place resistors on the breadboard. Use different values to test the circuit.

3. Connect Push Buttons:

   • Connect one side of each push button to ground.
   • Connect the other side to digital pins (e.g., pins 6 and 7).

Common Pitfall

Ensure all connections are secure and double-check the pin numbers to avoid confusion.

Step 3: Write the Arduino Code

Now, you'll write the code that will control your ohmmeter. Use the following code as a starting point:

#include <LiquidCrystal.h>

// Initialize the LCD
LiquidCrystal lcd(12, 11, 5, 4, 3, 2);

// Define button pins
const int button1 = 6;
const int button2 = 7;

void setup() {
  lcd.begin(16, 2);
  pinMode(button1, INPUT);
  pinMode(button2, INPUT);
}

void loop() {
  // Code to read resistance and display on LCD
}

Practical Tip

Test your code frequently by uploading it to the Arduino to catch any errors early.

Step 4: Implement the Resistance Measurement Logic

Enhance your code to measure resistance. Here's a basic example of how to do this:

int measureResistance() {
  // Logic to measure resistance
  // Return the measured value
}

void loop() {
  if (digitalRead(button1) == HIGH) {
    int resistance = measureResistance();
    lcd.print("Resistance: ");
    lcd.print(resistance);
  }
}

Explanation

The measureResistance function will contain the logic needed to calculate the resistance based on the input from your circuit.

Step 5: Calibrate Your Ohmmeter

After assembling your circuit and writing the code, it's essential to calibrate your ohmmeter. Use a multimeter to compare readings:

1. Measure a known resistor with the multimeter.
2. Run your Arduino ohmmeter.
3. Adjust your code as necessary to ensure accuracy.

Common Pitfall

Calibration is crucial; ensure you take your time to get accurate readings.

Conclusion

You've now created an automatic selection ohmmeter using Arduino! This project not only enhances your understanding of electronics but also gives you a hands-on tool for future projects. Consider expanding your skills by experimenting with different sensors or integrating more complex features into your ohmmeter. Happy building!