Dear friends welcome to another project video!
Today, we are going to use this small e-paper
display with the ESP32 board and build a simple
thermometer!
It is a very easy project to build.
It won’t take us more than 5 minutes so
let’s get started!
Hello, guys, I am Nick and welcome to educ8s.tv
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projects.
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Let’s see what we are going to build today.
As you can see, I have connected a small e-paper
screen to an ESP32 board.
At the screen, we display the temperature
which is being measured by this temperature
sensor the DS18B20.
The temperature reading on the screen is updated
every 5 seconds.
The cool thing is that we don’t refresh
the whole screen which is very slow, only
part of the screen which is fast and low-power!
Great, the project is working fine but let’s
now see how to build it!
The parts needed are the following:
• An ESP32 Board
• A 1.5 Inch E-Paper Display
• A DS18B20 Sensor
• A breadboard
• Some wires
The total cost of the project is around 30$.
You can find links to all the parts I use
in the description of the video below.
Let’s now connect them together.
A few days ago we took a first look at this
small e-paper display, and we built a small
project with it using an Arduino Uno board.
Unfortunately, the libraries for the screen
require a lot of RAM memory.
The Arduino Uno offers a limited amount of
memory just 2KBs so we can’t build big projects
with it using this e-paper display.
So we are going to use something more powerful.
Actually let’s use the most powerful board
we have, the ESP32.
As you can see, the ESP32 compared to an Arduino
Uno is a beast!
It offers two 32bit cores which operate at
160Mhz, 520KBs of RAM memory, WiFi, Bluetooth,
many analog and digital pins at a price of
just $7!
I prepared a detailed review of the ESP32
a few months ago; you can watch it by clicking
on the card here.
One of the most exciting things about the
ESP32 is that even though it is so powerful,
it offers a deep-sleep mode which requires
only 10μΑs of current.
This make the ESP32 the ideal chip for low
power applications.
The E-Paper screen uses the SPI interface
to communicate with the ESP32 board so we
must connect it to the hardware SPI pins of
the ESP32 board we use.
It took me some time to find out which pins
are the SPI pins on this board searching online.
After I discovered them, I designed this,
to save you some of your precious time.
You can find the pinout diagram of this ESP32
board in the description below.
Now that we know the pins we need all we have
to do is to connect the display and the sensor
to the ESP32 according to this schematic diagram.
Luckily all the SPI pin are placed on the
same side of this ESP32 board so we can use
a breadboard to test our project.
After connecting all the parts together all
we have to do is to power up the project.
At first, the project displays a splash screen
for 3 seconds and then it shows the temperature
icon.
A few moments later the temperature reading
appears.
The temperature reading is updated once every
5 seconds.
I have also prepared a version of the code
with the temperature displayed in degrees
Fahrenheit for the friends of the channel
living in the United States.
The code of the project is relatively simple.
We use the great GxEPD library to drive the
display and a library for the temperature
sensor.
At first we display the splash screen which
is a bitmap file designed in Photoshop.
Then we display another bitmap which is the
main GUI of the project.
The Wiki of the screen has detailed instructions
on how to load bitmap graphics on this screen.
In the loop function we read the temperature
every five seconds and we print the temperature
we read on the display.
We don’t refresh the whole display because
it takes a lot of time, only the temperature
part using the partial screen update function.
As always you can find the code of the project
in a link the description below.
The project works fine, and it looks great.
The e-paper display is ideal for a project
like this because it offers great readability
and extremely low-power consumption.
When the screen is not updating it needs only
0.02mAs of current!
The ESP32 board needs around 60mA of current
when operating.
In the next video, I will try to reduce the
power consumption of the project.
The goal is to make this project able to run
on batteries for months.
To achieve that I am going to learn how to
put the ESP32 to sleep to conserve power and
I am going to use another ESP32 board, the
Firebeetle ESP32 by DFrobot.
The creators of the board claim that this
board requires only 12μΑ of current in sleep
mode.
So, in theory, the DFrobot Firebeetle board
with an E-Paper display will need only 0.03mA
in sleep mode!
This means that we can easily make this project
last on batteries for over a year!
I can’t wait to try it and share my results
with you.
I would love to hear your opinion about this
project.
Are you going to build any project with an
ESP32 and an e-paper display?
Please post your ideas in the comments section
below; I love reading your thoughts!
If this is your first time here, I would love
to have you subscribed.
In this channel, I post videos about DIY projects
twice a month.
I love making things, and I believe that anyone
can make things, anyone can become a maker.
That’s why I created this channel, to share
my knowledge with the community and learn
from the community.
I hope you will join us.
I will see you in the next video!
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