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digital-voltmeter-with-arduino-nano-0221b6-en.md

Precision Measurement: The DIY Voltmeter

Ever wondered how much charge is left in an old battery? The Digital Voltmeter project teaches you how the Arduino’s ADC (Analog-to-Digital Converter) works and how to safely measure voltages higher than 5V.

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The Voltage Divider Concept

Since the Arduino can only accept up to 5V on its analog pins, we use a Voltage Divider (two resistors in series) to "scale down" higher voltages.

  • Ratio: If we use a 10k and a 100k resistor, we can safely measure up to 55V!
  • Conversion: The Arduino reads a value from 0-1023, and the code converts that value back into the actual voltage using a simple mathematical multiplier.

Key Hardware

  • Arduino Uno: The brain and the ADC.
  • Resistors (10k and 100k): For the voltage divider circuit.
  • 16x2 LCD Display: To show the measured voltage.
  • Probe Wires: To connect to the battery or power source being tested.

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Calibration and Safety

To make your voltmeter accurate, you must measure the exact resistance of your voltage divider resistors with a multimeter and update the values in your code. Safety Warning: This project is for DC voltage only. NEVER attempt to measure AC mains voltage with an Arduino, as it is extremely dangerous.

ข้อมูล Frontmatter ดั้งเดิม 

title: "Digital Voltmeter with Arduino"
description: "Build your own test equipment! Learn how to use an Arduino to measure voltage safely using a voltage divider circuit and display it on an LCD."
category: "Tools & Equipment"
difficulty: "Intermediate"