In my previous video, I showed you how to build a voltmeter using Arduino, but since the readings were displayed on the Serial Monitor, it wasn’t very portable. Now, let’s take it a step further by displaying the voltage readings on an LCD screen for a more practical and user-friendly experience.

To scale up our voltmeter, we’ll use a voltage divider to safely measure higher voltages. The components required are:

Components Required

1. 1 x ARDUINO UNO
2. 1 x LCD DISPLAY
3. 1 x I²C LCD CONVERTION MODULE
4. 1 x 10KΩ Resistor
5. 1 x 1KΩ Resistor
6. 1 x 10KΩ Trimmer pot (for calibration)

Connections

1. Connect the 10KΩ and 1KΩ resistors in series as shown in the diagram.
2. Tap the middle connection of the voltage divider and connect it to Analog Pin A0 of the Arduino UNO.
3. Upload the code (link in the description) and power up the circuit.
4. Apply a voltage to the divider and check the readings.

Calibration & Testing

• I’m using a variable power supply for the demonstration.
• To ensure accurate readings, adjust the trimmer screw until the display shows the correct voltage.
• Important: Make sure the ground of the voltage divider is connected to the Arduino’s ground.

Normal LCD Connections

Circuit Diagram

I²C LCD Connections

Circuit Diagram

Code for this can be found by clicking here

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