Arduino Voltmeter Project

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Arduino Voltmeter Project

Arduino Voltmeter DIY project

In this video we are going to learn how to build our own Arduino voltmeter using a very inexpensive sensor. The voltage we measure is then displayed in a Nokia 5110 LCD display. This project is very easy to build and great learning experience.

With this project we can measure the voltage of our voltage sources, or monitor the battery level of our projects. Let’s see the project in action. I have connected two wires to the voltage sensor module I am using today. I place the red wire to the positive terminal of an AA battery and the black wire to the negative terminal of the battery. In the display we get its voltage. Let’s now try this 18650 battery, we get 3.6V. Let’s now measure this big 12V battery. The voltage is 12.1V. If we compare the readings with a Multimeter, we can see that the measurements are really close! The project is working fine. But be careful, the maximum input voltage that this sensor can measure is 25V, so if you exceed it, you are going to burn your Arduino Pin. Let’s now see how to build this project.

The parts needed in order to build this Arduino Voltmeter project are these:


Arduino Uno:

Nokia 5110 LCD:

Voltage Sensor:

Small Breadboard:


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The connection with Arduino is very easy. We only have to connect two wires to Arduino. The pin with – sign goes to Arduino GND and the Signal pin which is marked with an S, goes to any analog pin of Arduino. I am using analog pin 0 today. That’s it. We can leave the positive pin unconnected, since it is not used at all by the module! Next we have to connect the Nokia 5110 LCD display. Please watch the detailed tutorial I have prepared on how to use the Nokia 5110 LCD display. That’s it, if we now power up the project, in the display a splash screen is displayed for a couple of seconds and after that we are ready to measure the voltage.

But now let’s see how this sensor module works. This voltage sensor is very simple. It consists of only two resistors! You can build your own easily if you wish, or you can buy this module sensor with less than a dollar if you want something already built. This is how it works. This sensor is actually a voltage divider. A voltage divider circuit is a very common circuit that takes a higher voltage and converts it to lower one by using a pair of resistors. The formula for calculating the output voltage is based on Ohms law.









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  1. Memfis August 6, 2016 at 7:30 pm - Reply

    Hello! Good device . Make please for nokia 1202 display .

  2. CHINTAN September 11, 2016 at 2:11 pm - Reply

    dear please make something for nokia 1202 LCD

  3. Muhammad Ilyas December 13, 2016 at 11:50 am - Reply

    dear sir the arduino code give a error in following. sir please help me

    VoltMeter:11: error: ‘LCD5110’ does not name a type
    VoltMeter.ino: In function ‘void setup()’:
    VoltMeter:30: error: ‘lcd’ was not declared in this scope
    VoltMeter.ino: In function ‘void loop()’:
    VoltMeter:39: error: ‘lcd’ was not declared in this scope
    VoltMeter.ino: In function ‘void displayVoltage(int)’:
    VoltMeter:68: error: ‘lcd’ was not declared in this scope

    • 404 February 4, 2017 at 2:26 pm - Reply

      You need ton install the Adafruit_Nokia5110 Library !

  4. Zis December 10, 2017 at 1:38 pm - Reply

    Hello look great Projeckt!
    Thank you.
    I have allowed myself to adjust the code a bit and extended the start screen with a warning logo “MAX 25V”

    In addition, I will replace the LED’s from the display with red LED’s, and pack the whole thing into a small building.

    A great project just makes it fun to build.

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