Dear friends welcome to another video! This
is Nick from educ8s.tv and today we are going to build this easy, but very useful Arduino
project. We are going to develop a digital voltmeter! Without any further delay, let’s
get started! In this video we are going to build this digital
voltmeter, a very easy to build project but very useful as well. 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 3.5V. 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 project are these:
• An Arduino Uno, or any other Arduino board with 5V logic levels
• A voltage sensor • A Nokia 5110 LCD display
• A breadboard • Some wires
The cost of the project is very low, it’s around $10. You can find links for all the
parts in the description of the video. 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 and
it is the following: In this module, the R1 is 30.000 Ohms, the
R2 is 7500 Ohms. If we put 25V on the input, if we make the calculations, we get 5V at
the output! And that’s the maximum voltage an analog pin of Arduino can handle. So, if
we exceed 25V at the input, we will burn the Analog pin of Arduino.
The Arduino Uno has
a 10bit ADC so the resolution that we can achieve using this sensor is 25mV. If we use
an Arduino Due, we can achieve even better resolution since it has 12bit ADCs. But, of
course, we need to build our own voltage sensor, because the Arduino Due board uses 3.3V logic
levels, and any voltage beyond that will destroy its analog pin. Let’s now see the software side of the project.
As you can see, the code of this project is extremely easy. All we need is a library for
the display and few lines of code. All we do is to read the value from the analog pin
0, make some calculations based on the formula we saw earlier and then we display the result
on the screen. As always you can find the code of this project in a link in the description
of the video.
As you can, we can easily build our own voltmeter
using Arduino and a simple sensor that we can easily build by ourselves. It is a very
easy project to build and in my opinion a very interesting one. Except from useful,
this project is also very educational. One can learn a lot from a project like this,
from voltage dividers, to ADCs. It’s great learning experience. I hope that you liked
it! If this is your first time here, I would love
to have you subscribed. In this channel I post videos about DIY projects every Saturday.
I love making things and I believe that anyone can make things, anyone can become a maker.
That’s why I created this channel, in order to share my knowledge with the community and
learn from the community.
I hope you will join us. Until next Saturday, Watch, Learn,
Build! [ Translating these subtitles? Add your name