Introduction: DIY Voltmeter Using Arduino and Processing

About: An Electronics engineer and a hobbyist. I love to keep experimenting with microcontrollers.

Hello and welcome to today's project. I'm Sarvesh and today

we will make an arduino based voltmeter. But what's different about this one is that it will show its output on the processing software. Now in one of my previous tutorial we made a processing based flappy bird by getting inputs from the arduino. This project is also similar to that one. We will measure the voltage using the analog input pin of the arduino. The input voltage can be high like 20 V and the arduino analog pin cannot measure that much voltage due to its resolution of 10 bits(1024)i.e. 5V. So we will use a resistor divider to bring this voltage down to a range of 0-30 V (512). Now let's make this project.

Step 1: Gather All the Required Supplies .

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1 X Arduino Pro Micro

1 X Resistor (10K and 100K ohm)


Male to male header wires

Batteries for testing


Step 2: Connections .

Do the connections as shown in the circuit diagram above.

Connect the two resistors in series and connect their centre point to Analog pin A0. Then connect the other end of 10K R to Gnd and the other end of 100K resistor to +5V. Now apply the test voltages to these two ends. That's it the connections are done.

Step 3: Upload Program to Your Arduino Board.

Now download the program given below and open it. Remember

to select the proper board before uploading the code. Here we used Arduino Pro Micro. If you are using an Arduino Uno then just keep in as it is. Now upload the code to the board.

Step 4: Open the Processing Sketch.

Download and open the processing sketch and make sure you

select the proper com port in the processing code. Now click on the run button and start measuring voltages at the - and + pins of the resistor divider. I have attached few images of my result. Hope you enjoy making this small voltmeter. You can also use a LCD and display voltage readings on it making it a portable digital voltmeter. You can also create your PCB and give this project a professional look. PCB Design Services That's it for today guys. See you'll soon with another project.