Voltage Meter

This is a project that implements a simple voltage meter using Arduino. The sensor's output voltage is converted by the ADC (Analog to Digital Converter) and displayed via the serial monitor.

Table of Contents

• Introduction
• Features
• Getting Started
  • Hardware Required
  • Software Required
  • Setup
• Code Explanation
• Usage
• License
• References

Introduction

This project demonstrates how to read an analog voltage using an Arduino and display the result on the serial monitor. The output voltage from a sensor is sampled and smoothed over multiple readings to provide a stable voltage measurement.

Features

• Reads analog voltage from a sensor.
• Uses ADC for voltage conversion.
• Prints the measured voltage to the serial monitor.
• Smoothes the voltage readings by averaging multiple samples.

Getting Started

Hardware Required

• Arduino UNO
• Voltage sensor
• Connecting wires

Software Required

• Arduino IDE

Setup

1. Connect the Hardware:

   • Connect the voltage sensor to the Arduino UNO. The signal pin of the sensor should be connected to the analog pin A0.

2. Upload the Code:

   • Open the Arduino IDE.
   • Copy the code from voltage_meter.ino and paste it into the Arduino IDE.
   • Select the correct board and port from the Tools menu.
   • Upload the code to the Arduino UNO.

Code Explanation

Preprocessor

#define sigPin A0 // Voltage meter signal pin w/ ADC
#define N 800     // Measurement sampling number for smoothing

• Defines the signal pin and the number of samples for smoothing.

Constants

const unsigned long baudSpeed = 115200UL;
const unsigned long period = 1000UL;
const float vIn = 5.0f;
const byte resBits = 10;
const float vConv = vIn / (pow(2.0, resBits) - 1.0f);

• Sets the baud rate for serial communication, the measurement period, and the voltage conversion constant.

Initialization

void setup(void) {
  Serial.begin(baudSpeed);
  pinMode(sigPin, INPUT);
  startTime = millis();
  measuredVoltage = 0.0f;
}

• Initializes the serial port and sets the signal pin as input.

Measurement Loop

void loop(void) {
  currentTime = millis();
  
  if ((currentTime - startTime) >= period) {
    getVolt(sigPin);

    Serial.print("Voltage: ");
    Serial.print(measuredVoltage, 4);
    Serial.println(" V");

    startTime = currentTime;
  } else {
    return;
  }
}

• Measures and prints the voltage every second.

Analog Voltage Reading

void getVolt(byte signalPin) {
  measuredVoltage = 0;
  for (unsigned int i = 0U; i < N; ++i) {
    measuredVoltage += analogRead(signalPin);
    delay(1UL);
  }
  measuredVoltage = (measuredVoltage * vConv) / N;

  if (isinf(measuredVoltage) || isnan(measuredVoltage)) {
    measuredVoltage = -1;
  }
}

• Reads the analog voltage multiple times and averages the result.

Usage

1. Connect the Arduino to your computer:
   • Open the serial monitor from the Arduino IDE.
   • Set the baud rate to 115200.
2. Observe the voltage readings:
   • The measured voltage will be printed every second on the serial monitor.

License

This project is licensed under the MIT License - see the LICENSE file for details.

References

• Voltmeter - Wikipedia