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!
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